代码注释

ActionFailureException.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**支持小米便签运行过程中的运行异常处理 */
+package net.micode.notes.gtask.exception;
+
+public class ActionFailureException extends RuntimeException {
+    private static final long serialVersionUID = 4425249765923293627L;
+/**serialVersionUID相当于java类的身份证，主要用于版本控制
+ * serialVersionUID作用是序列化时保持版本的兼容性，即在版本升级时反序列化仍保持对象的唯一性
+ */
+    public ActionFailureException() {
+        super();
+    }
+/**
+ * 在JAVA类中使用super来引用父类的成分，用this来引用当前对象
+ * 如果一个类从另一个类继承，我们new这个子类的实例对象的时候，这个子类对象里面会有一个父类对象，使用super引用父类对象
+ * 此处super（）及super（paramString）可认为是Exception（）和Exception（paramString）
+ */
+    public ActionFailureException(String paramString) {
+        super(paramString);
+    }
+
+    public ActionFailureException(String paramString, Throwable paramThrowable) {
+        super(paramString, paramThrowable);
+    }
+}

AlarmAlertActivity.java

@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;//定义一个名为net.micode.notes.ui的包
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
+import android.content.DialogInterface.OnDismissListener;
+import android.content.Intent;
+import android.media.AudioManager;
+import android.media.MediaPlayer;
+import android.media.RingtoneManager;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.PowerManager;
+import android.provider.Settings;
+import android.view.Window;
+import android.view.WindowManager;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.DataUtils;
+
+import java.io.IOException;
+
+
+public class AlarmAlertActivity extends Activity implements OnClickListener, OnDismissListener {
+    private long mNoteId; //文本在数据库存储中的ID号
+    private String mSnippet;//闹钟提示时出现的文本片段
+    private static final int SNIPPET_PREW_MAX_LEN = 60;
+    MediaPlayer mPlayer;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+         //Bundle类型的数据与Map类型的数据相似，都是以key-value的形式存储数据的
+        //onsaveInstanceState方法是用来保存Activity的状态的
+        //能从onCreate的参数savedInsanceState中获得状态数据
+        requestWindowFeature(Window.FEATURE_NO_TITLE);
+        //界面显示——无标题
+        final Window win = getWindow();
+        win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
+
+        if (!isScreenOn()) {
+            win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
+                    //保持窗体点亮
+                    | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
+                    //将窗体点亮
+                    | WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON
+                    //允许窗体点亮时锁屏
+                    | WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR);
+        }//在手机锁屏后如果到了闹钟提示时间，点亮屏幕
+
+        Intent intent = getIntent();
+
+        try {
+            mNoteId = Long.valueOf(intent.getData().getPathSegments().get(1));
+            mSnippet = DataUtils.getSnippetById(this.getContentResolver(), mNoteId);
+             //根据ID从数据库中获取标签的内容；
+            //getContentResolver（）是实现数据共享，实例存储。
+            mSnippet = mSnippet.length() > SNIPPET_PREW_MAX_LEN ? mSnippet.substring(0,
+                    SNIPPET_PREW_MAX_LEN) + getResources().getString(R.string.notelist_string_info)
+                    : mSnippet;
+            //判断标签片段是否达到符合长度
+        } catch (IllegalArgumentException e) {
+            e.printStackTrace();
+            return;
+        }
+
+        /*
+        try
+        {
+        	// 代码区
+        }
+        catch(Exception e)
+        {
+        	// 异常处理
+        }
+        代码区如果有错误，就会返回所写异常的处理。*/
+        mPlayer = new MediaPlayer();
+        if (DataUtils.visibleInNoteDatabase(getContentResolver(), mNoteId, Notes.TYPE_NOTE)) {
+            showActionDialog();
+            //弹出对话框
+            playAlarmSound();
+            //闹钟提示音激发
+        } else {
+            finish();
+            //完成闹钟动作
+        }
+    }
+
+    private boolean isScreenOn() {
+        //判断屏幕是否锁屏，调用系统函数判断，最后返回值是布尔类型
+        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
+        return pm.isScreenOn();
+    }
+
+    private void playAlarmSound() {
+        //闹钟提示音激发
+        Uri url = RingtoneManager.getActualDefaultRingtoneUri(this, RingtoneManager.TYPE_ALARM);
+        //调用系统的铃声管理URI，得到闹钟提示音
+        int silentModeStreams = Settings.System.getInt(getContentResolver(),
+                Settings.System.MODE_RINGER_STREAMS_AFFECTED, 0);
+
+        if ((silentModeStreams & (1 << AudioManager.STREAM_ALARM)) != 0) {
+            mPlayer.setAudioStreamType(silentModeStreams);
+        } else {
+            mPlayer.setAudioStreamType(AudioManager.STREAM_ALARM);
+        }
+        try {
+            mPlayer.setDataSource(this, url);
+            //方法：setDataSource(Context context, Uri uri) 
+            //解释：无返回值，设置多媒体数据来源【根据 Uri】
+            mPlayer.prepare();
+            //准备同步
+            mPlayer.setLooping(true);
+            //设置是否循环播放
+            mPlayer.start();
+            //开始播放
+        } catch (IllegalArgumentException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+            //e.printStackTrace()函数功能是抛出异常， 还将显示出更深的调用信息
+            //System.out.println(e)，这个方法打印出异常，并且输出在哪里出现的异常
+        } catch (SecurityException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (IllegalStateException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+    }
+
+    private void showActionDialog() {
+        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
+        //AlertDialog的构造方法全部是Protected的
+        //所以不能直接通过new一个AlertDialog来创建出一个AlertDialog。
+        //要创建一个AlertDialog，就要用到AlertDialog.Builder中的create()方法
+        //如这里的dialog就是新建了一个AlertDialog
+        dialog.setTitle(R.string.app_name);
+        //为对话框设置标题
+        dialog.setMessage(mSnippet);
+        //为对话框设置内容
+        dialog.setPositiveButton(R.string.notealert_ok, this);
+        //给对话框添加"Yes"按钮
+        if (isScreenOn()) {
+            dialog.setNegativeButton(R.string.notealert_enter, this);
+        }//对话框添加"No"按钮
+        dialog.show().setOnDismissListener(this);
+    }
+
+    public void onClick(DialogInterface dialog, int which) {
+        switch (which) {
+            //用which来选择click后下一步的操作
+            case DialogInterface.BUTTON_NEGATIVE:
+                //这是取消操作
+                Intent intent = new Intent(this, NoteEditActivity.class);
+                //实现两个类间的数据传输
+                intent.setAction(Intent.ACTION_VIEW);
+                //设置动作属性
+                intent.putExtra(Intent.EXTRA_UID, mNoteId);
+                //实现key-value对
+                //EXTRA_UID为key；mNoteId为键
+                startActivity(intent);
+                //开始动作
+                break;
+            default:
+                //这是确定操作
+                break;
+        }
+    }
+
+    public void onDismiss(DialogInterface dialog) {
+        //忽略
+        stopAlarmSound();
+        //停止闹钟声音
+        finish();
+        //完成该动作
+    }
+
+    private void stopAlarmSound() {
+        if (mPlayer != null) {
+            mPlayer.stop();
+            //停止播放
+            mPlayer.release();
+            //释放MediaPlayer对象
+            mPlayer = null;
+        }
+    }
+}

AlarmInitReceiver.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.app.AlarmManager;
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.ContentUris;
+import android.content.Context;
+import android.content.Intent;
+import android.database.Cursor;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+
+
+public class AlarmInitReceiver extends BroadcastReceiver {
+
+    private static final String [] PROJECTION = new String [] {
+        NoteColumns.ID,
+        NoteColumns.ALERTED_DATE
+    };
+//对数据库的操作，调用标签ID和闹钟时间
+    private static final int COLUMN_ID                = 0;
+    private static final int COLUMN_ALERTED_DATE      = 1;
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        long currentDate = System.currentTimeMillis();
+        //System.currentTimeMillis()产生一个当前的毫秒
+        //这个毫秒其实就是自1970年1月1日0时起的毫秒数
+        Cursor c = context.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+                PROJECTION,
+                NoteColumns.ALERTED_DATE + ">? AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE,
+                new String[] { String.valueOf(currentDate) },
+                //将long变量currentDate转化为字符串
+                null);
+        //Cursor在这里的作用是通过查找数据库中的标签内容，找到和当前系统时间相等的标签
+        if (c != null) {
+            if (c.moveToFirst()) {
+                do {
+                    long alertDate = c.getLong(COLUMN_ALERTED_DATE);
+                    Intent sender = new Intent(context, AlarmReceiver.class);
+                    sender.setData(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, c.getLong(COLUMN_ID)));
+                    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, sender, 0);
+                    AlarmManager alermManager = (AlarmManager) context
+                            .getSystemService(Context.ALARM_SERVICE);
+                    alermManager.set(AlarmManager.RTC_WAKEUP, alertDate, pendingIntent);
+                } while (c.moveToNext());
+            }
+            c.close();
+        }
+        //然而通过网上查找资料发现，对于闹钟机制的启动，通常需要上面的几个步骤
+        //如新建Intent、PendingIntent以及AlarmManager等
+        //这里就是根据数据库里的闹钟时间创建一个闹钟机制
+    }
+}

AlarmReceiver.java

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+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+public class AlarmReceiver extends BroadcastReceiver {
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        intent.setClass(context, AlarmAlertActivity.class);
+        //启动AlarmAlertActivity
+        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        //activity要存在于activity的栈中，而非activity的途径启动activity时必然不存在一个activity的栈
+        //所以要新起一个栈装入启动的activity
+        context.startActivity(intent);
+    }
+}
+/**
+*这是实现alarm这个功能最接近用户层的包，基于上面的两个包，
+*作用还需要深究
+ */

BackupUtils.java

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+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.tool;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.os.Environment;
+import android.text.TextUtils;
+import android.text.format.DateFormat;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+
+
+public class BackupUtils {
+    private static final String TAG = "BackupUtils";
+    // Singleton stuff
+    private static BackupUtils sInstance;
+
+    public static synchronized BackupUtils getInstance(Context context) {
+        //synchronized关键字，代表这个方法加锁，相当于不管哪一个线程（例如线程A）
+        //运行到这个方法时，都要检查有没有其他线程B（或者C、D等）正在用这个方法（或者该类的其他同步方法），有的话要等正在使用synchronized方法的线程B（或者C、D）
+        //运行完这个方法后再运行此线程A，没有的话，锁定调用者，然后直接运行
+        //它包括两种方法：synchronized方法和synchronized块
+        if (sInstance == null) {
+            //如果当前备份不存在，则新声明一个
+            sInstance = new BackupUtils(context);
+        }
+        return sInstance;
+    }
+
+    /**
+     * Following states are signs to represents backup or restore
+     * status
+     */
+    // Currently, the sdcard is not mounted SD卡没有被装入手机
+    public static final int STATE_SD_CARD_UNMOUONTED           = 0;
+    // The backup file not exist 备份文件夹不存在
+    public static final int STATE_BACKUP_FILE_NOT_EXIST        = 1;
+    // The data is not well formated, may be changed by other programs 数据已被破坏，可能被修改
+    public static final int STATE_DATA_DESTROIED               = 2;
+    // Some run-time exception which causes restore or backup fails  超时异常
+    public static final int STATE_SYSTEM_ERROR                 = 3;
+    // Backup or restore success  成功存储
+    public static final int STATE_SUCCESS                      = 4;
+
+    private TextExport mTextExport;
+
+    private BackupUtils(Context context) {//初始化函数
+        mTextExport = new TextExport(context);
+    }
+
+    private static boolean externalStorageAvailable() {//外部存储功能是否可用
+        return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
+    }
+
+    public int exportToText() {
+        return mTextExport.exportToText();
+    }
+
+    public String getExportedTextFileName() {
+        return mTextExport.mFileName;
+    }
+
+    public String getExportedTextFileDir() {
+        return mTextExport.mFileDirectory;
+    }
+
+    private static class TextExport {
+        private static final String[] NOTE_PROJECTION = {
+                NoteColumns.ID,
+                NoteColumns.MODIFIED_DATE,
+                NoteColumns.SNIPPET,
+                NoteColumns.TYPE
+        };
+
+        private static final int NOTE_COLUMN_ID = 0;
+
+        private static final int NOTE_COLUMN_MODIFIED_DATE = 1;
+
+        private static final int NOTE_COLUMN_SNIPPET = 2;
+
+        private static final String[] DATA_PROJECTION = {
+                DataColumns.CONTENT,
+                DataColumns.MIME_TYPE,
+                DataColumns.DATA1,
+                DataColumns.DATA2,
+                DataColumns.DATA3,
+                DataColumns.DATA4,
+        };
+
+        private static final int DATA_COLUMN_CONTENT = 0;
+
+        private static final int DATA_COLUMN_MIME_TYPE = 1;
+
+        private static final int DATA_COLUMN_CALL_DATE = 2;
+
+        private static final int DATA_COLUMN_PHONE_NUMBER = 4;
+
+        private final String [] TEXT_FORMAT;
+        private static final int FORMAT_FOLDER_NAME          = 0;
+        private static final int FORMAT_NOTE_DATE            = 1;
+        private static final int FORMAT_NOTE_CONTENT         = 2;
+
+        private Context mContext;
+        private String mFileName;
+        private String mFileDirectory;
+
+        public TextExport(Context context) {
+            TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note);
+            mContext = context;
+            mFileName = "";
+            mFileDirectory = "";
+        }
+
+        private String getFormat(int id) {//获取文本的组成部分
+            return TEXT_FORMAT[id];
+        }
+
+        /**
+         * Export the folder identified by folder id to text
+         */
+        private void exportFolderToText(String folderId, PrintStream ps) {
+            // Query notes belong to this folder 通过查询parent id是文件夹id的note来选出制定ID文件夹下的note
+            Cursor notesCursor = mContext.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION, NoteColumns.PARENT_ID + "=?", new String[] {
+                        folderId
+                    }, null);
+
+            if (notesCursor != null) {
+                if (notesCursor.moveToFirst()) {
+                    do {
+                        // Print note's last modified date  ps里面保存有这份note的日期
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+                                mContext.getString(R.string.format_datetime_mdhm),
+                                notesCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // Query data belong to this note
+                        String noteId = notesCursor.getString(NOTE_COLUMN_ID);
+                        exportNoteToText(noteId, ps);//将文件导出到text
+                    } while (notesCursor.moveToNext());
+                }
+                notesCursor.close();
+            }
+        }
+
+        /**
+         * Export note identified by id to a print stream
+         */
+        private void exportNoteToText(String noteId, PrintStream ps) {
+            Cursor dataCursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI,
+                    DATA_PROJECTION, DataColumns.NOTE_ID + "=?", new String[] {
+                        noteId
+                    }, null);
+
+            if (dataCursor != null) {//利用光标来扫描内容，区别为callnote和note两种，靠ps.printline输出
+                if (dataCursor.moveToFirst()) {
+                    do {
+                        String mimeType = dataCursor.getString(DATA_COLUMN_MIME_TYPE);
+                        if (DataConstants.CALL_NOTE.equals(mimeType)) {
+                            // Print phone number
+                            String phoneNumber = dataCursor.getString(DATA_COLUMN_PHONE_NUMBER);
+                            long callDate = dataCursor.getLong(DATA_COLUMN_CALL_DATE);
+                            String location = dataCursor.getString(DATA_COLUMN_CONTENT);
+
+                            if (!TextUtils.isEmpty(phoneNumber)) {//判断是否为空字符
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        phoneNumber));
+                            }
+                            // Print call date
+                            ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), DateFormat
+                                    .format(mContext.getString(R.string.format_datetime_mdhm),
+                                            callDate)));
+                            // Print call attachment location
+                            if (!TextUtils.isEmpty(location)) {
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        location));
+                            }
+                        } else if (DataConstants.NOTE.equals(mimeType)) {
+                            String content = dataCursor.getString(DATA_COLUMN_CONTENT);
+                            if (!TextUtils.isEmpty(content)) {
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        content));
+                            }
+                        }
+                    } while (dataCursor.moveToNext());
+                }
+                dataCursor.close();
+            }
+            // print a line separator between note
+            try {
+                ps.write(new byte[] {
+                        Character.LINE_SEPARATOR, Character.LETTER_NUMBER
+                });
+            } catch (IOException e) {
+                Log.e(TAG, e.toString());
+            }
+        }
+
+        /**
+         * Note will be exported as text which is user readable
+         */
+        public int exportToText() {//总函数，调用上面的exportFolder和exportNote
+            if (!externalStorageAvailable()) {
+                Log.d(TAG, "Media was not mounted");
+                return STATE_SD_CARD_UNMOUONTED;
+            }
+
+            PrintStream ps = getExportToTextPrintStream();
+            if (ps == null) {
+                Log.e(TAG, "get print stream error");
+                return STATE_SYSTEM_ERROR;
+            } 
+            // First export folder and its notes 导出文件夹，就是导出里面包含的便签
+            Cursor folderCursor = mContext.getContentResolver().query(
+                    Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION,
+                    "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND "
+                            + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + ") OR "
+                            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null);
+
+            if (folderCursor != null) {
+                if (folderCursor.moveToFirst()) {
+                    do {
+                        // Print folder's name
+                        String folderName = "";
+                        if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) {
+                            folderName = mContext.getString(R.string.call_record_folder_name);
+                        } else {
+                            folderName = folderCursor.getString(NOTE_COLUMN_SNIPPET);
+                        }
+                        if (!TextUtils.isEmpty(folderName)) {
+                            ps.println(String.format(getFormat(FORMAT_FOLDER_NAME), folderName));
+                        }
+                        String folderId = folderCursor.getString(NOTE_COLUMN_ID);
+                        exportFolderToText(folderId, ps);
+                    } while (folderCursor.moveToNext());
+                }
+                folderCursor.close();
+            }
+
+            // Export notes in root's folder
+            //将根目录里的文件导出（由于不属于任何文件夹，因此无法通过文件夹导出来实现这一部分便签的导出）
+            Cursor noteCursor = mContext.getContentResolver().query(
+                    Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION,
+                    NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID
+                            + "=0", null, null);
+
+            if (noteCursor != null) {
+                if (noteCursor.moveToFirst()) {
+                    do {
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+                                mContext.getString(R.string.format_datetime_mdhm),
+                                noteCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // Query data belong to this note
+                        String noteId = noteCursor.getString(NOTE_COLUMN_ID);
+                        exportNoteToText(noteId, ps);
+                    } while (noteCursor.moveToNext());
+                }
+                noteCursor.close();
+            }
+            ps.close();
+
+            return STATE_SUCCESS;
+        }
+
+        /**
+         * Get a print stream pointed to the file {@generateExportedTextFile}
+         */
+        private PrintStream getExportToTextPrintStream() {
+            File file = generateFileMountedOnSDcard(mContext, R.string.file_path,
+                    R.string.file_name_txt_format);
+            if (file == null) {
+                Log.e(TAG, "create file to exported failed");
+                return null;
+            }
+            mFileName = file.getName();
+            mFileDirectory = mContext.getString(R.string.file_path);
+            PrintStream ps = null;
+            try {
+                FileOutputStream fos = new FileOutputStream(file);
+                ps = new PrintStream(fos);//将ps输出流输出到特定的文件，目的就是导出到文件，而不是直接输出
+            } catch (FileNotFoundException e) {
+                e.printStackTrace();
+                return null;
+            } catch (NullPointerException e) {
+                e.printStackTrace();
+                return null;
+            }
+            return ps;
+        }
+    }
+
+    /**
+     * Generate the text file to store imported data
+     */
+    private static File generateFileMountedOnSDcard(Context context, int filePathResId, int fileNameFormatResId) {
+        StringBuilder sb = new StringBuilder();
+        sb.append(Environment.getExternalStorageDirectory());//外部（SD卡）的存储路径
+        sb.append(context.getString(filePathResId));//文件的存储路径
+        File filedir = new File(sb.toString());//filedir应该就是用来存储路径信息
+        sb.append(context.getString(
+                fileNameFormatResId,
+                DateFormat.format(context.getString(R.string.format_date_ymd),
+                        System.currentTimeMillis())));
+        File file = new File(sb.toString());
+
+        try {//如果这些文件不存在，则新建
+            if (!filedir.exists()) {
+                filedir.mkdir();
+            }
+            if (!file.exists()) {
+                file.createNewFile();
+            }
+            return file;
+        } catch (SecurityException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+//try catch 异常处理
+        return null;
+    }
+}
+
+

Contact.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.provider.ContactsContract.CommonDataKinds.Phone;
+import android.provider.ContactsContract.Data;
+import android.telephony.PhoneNumberUtils;
+import android.util.Log;
+
+import java.util.HashMap;
+
+public class Contact {//联系人
+    private static HashMap<String, String> sContactCache;
+    private static final String TAG = "Contact";
+ // 定义字符串CALLER_ID_SELECTION
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
+    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+    + " AND " + Data.RAW_CONTACT_ID + " IN "
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+// 获取联系人
+    public static String getContact(Context context, String phoneNumber) {
+        if(sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+       // 查找HashMap中是否已有phoneNumber信息
+        if(sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 查找数据库中phoneNumber的信息
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,
+                new String [] { Phone.DISPLAY_NAME },
+                selection,
+                new String[] { phoneNumber },
+                null);
+        // 判定查询结果 
+        // moveToFirst()返回第一条
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                  // 找到相关信息
+                String name = cursor.getString(0);
+                sContactCache.put(phoneNumber, name);
+                return name;
+                //异常
+            } catch (IndexOutOfBoundsException e) {
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                cursor.close();
+            }
+            // 未找到相关信息
+        } else {
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}

DataUtils.java

@@ -0,0 +1,297 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.tool;
+
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderResult;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.OperationApplicationException;
+import android.database.Cursor;
+import android.os.RemoteException;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+
+public class DataUtils {
+    public static final String TAG = "DataUtils";
+    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {//直接删除多个笔记
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+        if (ids.size() == 0) {
+            Log.d(TAG, "no id is in the hashset");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();//提供一个任务列表
+        for (long id : ids) {
+            if(id == Notes.ID_ROOT_FOLDER) {
+                Log.e(TAG, "Don't delete system folder root");
+                continue;
+            }//如果发现是根文件夹，则不删除
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));//用newDelete实现删除功能
+            operationList.add(builder.build());
+        }
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);//主机名（或叫AUTHORITY）用以唯一标识这个ContentProvider，
+            //外部调用者可以根据这个标识来找到它。
+            //数据库事务，数据库事务是由一组数据库操作序列组成，事务作为一个整体被执行
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+
+    public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.PARENT_ID, desFolderId);
+        values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
+        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);//对需要移动的便签进行数据更新，然后用update实现
+    }
+
+    public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
+            long folderId) {
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+        for (long id : ids) {
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));//通过withAppendedId方法，为该uri加上id
+            builder.withValue(NoteColumns.PARENT_ID, folderId);
+            builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
+            operationList.add(builder.build());
+        }//将ids里包含的每一列的数据逐次加入到operationList中，等待最后的批量处理
+
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);//applyBatch一次性处理一个操作列表
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+
+    /**
+     * Get the all folder count except system folders {@link Notes#TYPE_SYSTEM}}
+     */
+    public static int getUserFolderCount(ContentResolver resolver) {
+        Cursor cursor =resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { "COUNT(*)" },
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+                new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
+                null);//筛选条件：源文件不为trash folder
+
+        int count = 0;
+        if(cursor != null) {
+            if(cursor.moveToFirst()) {
+                try {
+                    count = cursor.getInt(0);
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "get folder count failed:" + e.toString());
+                } finally {
+                    cursor.close();
+                }
+            }
+        }
+        return count;
+    }
+
+    public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),//通过withAppendedId方法，为该uri加上id
+                null,
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
+                new String [] {String.valueOf(type)},
+                null);//查询条件：type符合，且不属于垃圾文件夹
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {//用getcount函数判断cursor是否为空
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
+                null, null, null, null);
+//通过名字查询文件是否存在
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
+                NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER +
+                " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
+                " AND " + NoteColumns.SNIPPET + "=?",
+                new String[] { name }, null);
+        boolean exist = false;
+        if(cursor != null) {
+            if(cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
+        Cursor c = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
+                NoteColumns.PARENT_ID + "=?",
+                new String[] { String.valueOf(folderId) },
+                null);//查询条件：父id是传入的folderId
+
+        HashSet<AppWidgetAttribute> set = null;
+        if (c != null) {
+            if (c.moveToFirst()) {
+                set = new HashSet<AppWidgetAttribute>();
+                do {
+                    try {
+                        AppWidgetAttribute widget = new AppWidgetAttribute();
+                        widget.widgetId = c.getInt(0);//0对应的NoteColumns.WIDGET_ID
+                        widget.widgetType = c.getInt(1);//1对应的NoteColumns.WIDGET_TYPE
+                        set.add(widget);
+                    } catch (IndexOutOfBoundsException e) {
+                        Log.e(TAG, e.toString());
+                    }
+                } while (c.moveToNext());//查询下一条
+            }
+            c.close();
+        }
+        return set;
+    }
+
+    public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.PHONE_NUMBER },
+                CallNote.NOTE_ID + "=? AND " + CallNote.MIME_TYPE + "=?",
+                new String [] { String.valueOf(noteId), CallNote.CONTENT_ITEM_TYPE },
+                null);
+
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                return cursor.getString(0);
+            } catch (IndexOutOfBoundsException e) {
+                Log.e(TAG, "Get call number fails " + e.toString());
+            } finally {
+                cursor.close();
+            }
+        }
+        return "";
+    }
+
+    public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.NOTE_ID },
+                CallNote.CALL_DATE + "=? AND " + CallNote.MIME_TYPE + "=? AND PHONE_NUMBERS_EQUAL("
+                + CallNote.PHONE_NUMBER + ",?)",
+                new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
+                null);
+//通过数据库操作，查询条件是（CallNote和PhoneNumber匹配传入参数的值）
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                try {
+                    return cursor.getLong(0);//0对应的CallNote.NOTE_ID
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "Get call note id fails " + e.toString());
+                }
+            }
+            cursor.close();
+        }
+        return 0;
+    }
+
+    public static String getSnippetById(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String [] { NoteColumns.SNIPPET },
+                NoteColumns.ID + "=?",
+                new String [] { String.valueOf(noteId)},
+                null);//查询数据：noteId
+
+        if (cursor != null) {
+            String snippet = "";
+            if (cursor.moveToFirst()) {
+                snippet = cursor.getString(0);
+            }
+            cursor.close();
+            return snippet;
+        }
+        throw new IllegalArgumentException("Note is not found with id: " + noteId);
+    }
+
+    public static String getFormattedSnippet(String snippet) {//对字符串进行格式处理，将字符串两头的空格去掉，同时将换行符去掉
+        if (snippet != null) {
+            snippet = snippet.trim();
+            int index = snippet.indexOf('\n');
+            if (index != -1) {
+                snippet = snippet.substring(0, index);
+            }
+        }
+        return snippet;
+    }
+}

DateTimePicker.java

@@ -0,0 +1,505 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import java.text.DateFormatSymbols;
+import java.util.Calendar;
+
+import net.micode.notes.R;
+
+
+import android.content.Context;
+import android.text.format.DateFormat;
+import android.view.View;
+import android.widget.FrameLayout;
+import android.widget.NumberPicker;
+
+public class DateTimePicker extends FrameLayout {
+//FrameLayout是布局模板之一
+//所有的子元素全部在屏幕的右上方
+    private static final boolean DEFAULT_ENABLE_STATE = true;
+
+    private static final int HOURS_IN_HALF_DAY = 12;
+    private static final int HOURS_IN_ALL_DAY = 24;
+    private static final int DAYS_IN_ALL_WEEK = 7;
+    private static final int DATE_SPINNER_MIN_VAL = 0;
+    private static final int DATE_SPINNER_MAX_VAL = DAYS_IN_ALL_WEEK - 1;
+    private static final int HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW = 0;
+    private static final int HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW = 23;
+    private static final int HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW = 1;
+    private static final int HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW = 12;
+    private static final int MINUT_SPINNER_MIN_VAL = 0;
+    private static final int MINUT_SPINNER_MAX_VAL = 59;
+    private static final int AMPM_SPINNER_MIN_VAL = 0;
+    private static final int AMPM_SPINNER_MAX_VAL = 1;
+//初始化控件
+    private final NumberPicker mDateSpinner;
+    private final NumberPicker mHourSpinner;
+    private final NumberPicker mMinuteSpinner;
+    private final NumberPicker mAmPmSpinner;
+ //NumberPicker是数字选择器
+//这里定义的四个变量全部是在设置闹钟时需要选择的变量（如日期、时、分、上午或者下午）
+    private Calendar mDate;
+//定义了Calendar类型的变量mDate，用于操作时间
+    private String[] mDateDisplayValues = new String[DAYS_IN_ALL_WEEK];
+
+    private boolean mIsAm;
+
+    private boolean mIs24HourView;
+
+    private boolean mIsEnabled = DEFAULT_ENABLE_STATE;
+
+    private boolean mInitialising;
+
+    private OnDateTimeChangedListener mOnDateTimeChangedListener;
+
+    private NumberPicker.OnValueChangeListener mOnDateChangedListener = new NumberPicker.OnValueChangeListener() {
+        @Override
+        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
+            mDate.add(Calendar.DAY_OF_YEAR, newVal - oldVal);
+            updateDateControl();
+            onDateTimeChanged();
+        }
+    };//OnValueChangeListener，这是时间改变监听器，这里主要是对日期的监听
+    //将现在日期的值传递给mDate；updateDateControl是同步操作
+
+    private NumberPicker.OnValueChangeListener mOnHourChangedListener = new NumberPicker.OnValueChangeListener() {
+        //这里是对 小时（Hour） 的监听
+        @Override
+        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
+            boolean isDateChanged = false;
+            Calendar cal = Calendar.getInstance();
+            //声明一个Calendar的变量cal，便于后续的操作
+            if (!mIs24HourView) {
+                if (!mIsAm && oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY) {
+                    cal.setTimeInMillis(mDate.getTimeInMillis());
+                    cal.add(Calendar.DAY_OF_YEAR, 1);
+                    isDateChanged = true;
+                    //这里是对于12小时制时，晚上11点和12点交替时对日期的更改
+                } else if (mIsAm && oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
+                    cal.setTimeInMillis(mDate.getTimeInMillis());
+                    cal.add(Calendar.DAY_OF_YEAR, -1);
+                    isDateChanged = true;
+                }
+                //这里是对于12小时制时，凌晨11点和12点交替时对日期的更改
+                if (oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY ||
+                        oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
+                    mIsAm = !mIsAm;
+                    updateAmPmControl();
+                }//这里是对于12小时制时，中午11点和12点交替时对AM和PM的更改
+            } else {
+                if (oldVal == HOURS_IN_ALL_DAY - 1 && newVal == 0) {
+                    cal.setTimeInMillis(mDate.getTimeInMillis());
+                    cal.add(Calendar.DAY_OF_YEAR, 1);
+                    isDateChanged = true;
+                    //这里是对于24小时制时，晚上11点和12点交替时对日期的更改
+                } else if (oldVal == 0 && newVal == HOURS_IN_ALL_DAY - 1) {
+                    cal.setTimeInMillis(mDate.getTimeInMillis());
+                    cal.add(Calendar.DAY_OF_YEAR, -1);
+                    isDateChanged = true;
+                }
+            }//这里是对于12小时制时，凌晨11点和12点交替时对日期的更改
+            int newHour = mHourSpinner.getValue() % HOURS_IN_HALF_DAY + (mIsAm ? 0 : HOURS_IN_HALF_DAY);
+            //通过数字选择器对newHour的赋值
+            mDate.set(Calendar.HOUR_OF_DAY, newHour);
+            //通过set函数将新的Hour值传给mDate
+            onDateTimeChanged();
+            if (isDateChanged) {
+                setCurrentYear(cal.get(Calendar.YEAR));
+                setCurrentMonth(cal.get(Calendar.MONTH));
+                setCurrentDay(cal.get(Calendar.DAY_OF_MONTH));
+            }
+        }
+    };
+
+    private NumberPicker.OnValueChangeListener mOnMinuteChangedListener = new NumberPicker.OnValueChangeListener() {
+        @Override
+        //这里是对 分钟（Minute）改变的监听
+        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
+            int minValue = mMinuteSpinner.getMinValue();
+            int maxValue = mMinuteSpinner.getMaxValue();
+            int offset = 0;
+            //设置offset，作为小时改变的一个记录数据
+            if (oldVal == maxValue && newVal == minValue) {
+                offset += 1;
+            } else if (oldVal == minValue && newVal == maxValue) {
+                offset -= 1;
+            }
+            //如果原值为59，新值为0，则offset加1
+            //如果原值为0，新值为59，则offset减1
+            if (offset != 0) {
+                mDate.add(Calendar.HOUR_OF_DAY, offset);
+                mHourSpinner.setValue(getCurrentHour());
+                updateDateControl();
+                int newHour = getCurrentHourOfDay();
+                if (newHour >= HOURS_IN_HALF_DAY) {
+                    mIsAm = false;
+                    updateAmPmControl();
+                } else {
+                    mIsAm = true;
+                    updateAmPmControl();
+                }
+            }
+            mDate.set(Calendar.MINUTE, newVal);
+            onDateTimeChanged();
+        }
+    };
+
+    private NumberPicker.OnValueChangeListener mOnAmPmChangedListener = new NumberPicker.OnValueChangeListener() {
+        //对AM和PM的监听
+        @Override
+        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
+            mIsAm = !mIsAm;
+            if (mIsAm) {
+                mDate.add(Calendar.HOUR_OF_DAY, -HOURS_IN_HALF_DAY);
+            } else {
+                mDate.add(Calendar.HOUR_OF_DAY, HOURS_IN_HALF_DAY);
+            }
+            updateAmPmControl();
+            onDateTimeChanged();
+        }
+    };
+
+    public interface OnDateTimeChangedListener {
+        void onDateTimeChanged(DateTimePicker view, int year, int month,
+                int dayOfMonth, int hourOfDay, int minute);
+    }
+
+    public DateTimePicker(Context context) {
+        this(context, System.currentTimeMillis());
+    }//通过对数据库的访问，获取当前的系统时间
+
+    public DateTimePicker(Context context, long date) {
+        this(context, date, DateFormat.is24HourFormat(context));
+    }//上面函数的得到的是一个天文数字（1970至今的秒数），需要DateFormat将其变得有意义
+
+    public DateTimePicker(Context context, long date, boolean is24HourView) {
+        super(context);
+        //获取系统时间
+        mDate = Calendar.getInstance();
+        mInitialising = true;
+        mIsAm = getCurrentHourOfDay() >= HOURS_IN_HALF_DAY;
+        inflate(context, R.layout.datetime_picker, this);
+        //如果当前Activity里用到别的layout，比如对话框layout
+        //还要设置这个layout上的其他组件的内容，就必须用inflate()方法先将对话框的layout找出来
+        //然后再用findViewById()找到它上面的其它组件
+        mDateSpinner = (NumberPicker) findViewById(R.id.date);
+        mDateSpinner.setMinValue(DATE_SPINNER_MIN_VAL);
+        mDateSpinner.setMaxValue(DATE_SPINNER_MAX_VAL);
+        mDateSpinner.setOnValueChangedListener(mOnDateChangedListener);
+
+        mHourSpinner = (NumberPicker) findViewById(R.id.hour);
+        mHourSpinner.setOnValueChangedListener(mOnHourChangedListener);
+        mMinuteSpinner =  (NumberPicker) findViewById(R.id.minute);
+        mMinuteSpinner.setMinValue(MINUT_SPINNER_MIN_VAL);
+        mMinuteSpinner.setMaxValue(MINUT_SPINNER_MAX_VAL);
+        mMinuteSpinner.setOnLongPressUpdateInterval(100);
+        mMinuteSpinner.setOnValueChangedListener(mOnMinuteChangedListener);
+
+        String[] stringsForAmPm = new DateFormatSymbols().getAmPmStrings();
+        mAmPmSpinner = (NumberPicker) findViewById(R.id.amPm);
+        mAmPmSpinner.setMinValue(AMPM_SPINNER_MIN_VAL);
+        mAmPmSpinner.setMaxValue(AMPM_SPINNER_MAX_VAL);
+        mAmPmSpinner.setDisplayedValues(stringsForAmPm);
+        mAmPmSpinner.setOnValueChangedListener(mOnAmPmChangedListener);
+
+        // update controls to initial state
+        updateDateControl();
+        updateHourControl();
+        updateAmPmControl();
+
+        set24HourView(is24HourView);
+
+        // set to current time
+        setCurrentDate(date);
+
+        setEnabled(isEnabled());
+
+        // set the content descriptions
+        mInitialising = false;
+    }
+
+    @Override
+    public void setEnabled(boolean enabled) {
+        if (mIsEnabled == enabled) {
+            return;
+        }
+        super.setEnabled(enabled);
+        mDateSpinner.setEnabled(enabled);
+        mMinuteSpinner.setEnabled(enabled);
+        mHourSpinner.setEnabled(enabled);
+        mAmPmSpinner.setEnabled(enabled);
+        mIsEnabled = enabled;
+    }
+//下面的各函数主要是对上面代码引用到的个函数功能的实现
+    @Override
+    public boolean isEnabled() {
+        return mIsEnabled;
+    }
+
+    /**
+     * Get the current date in millis
+     *
+     * @return the current date in millis
+     */
+    public long getCurrentDateInTimeMillis() {
+        return mDate.getTimeInMillis();
+    }//实现函数——得到当前的秒数
+
+    /**
+     * Set the current date
+     *
+     * @param date The current date in millis
+     */
+    public void setCurrentDate(long date) {
+        Calendar cal = Calendar.getInstance();
+        cal.setTimeInMillis(date);
+        setCurrentDate(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH),
+                cal.get(Calendar.HOUR_OF_DAY), cal.get(Calendar.MINUTE));
+    }//实现函数功能——设置当前的时间，参数是date
+
+    /**
+     * Set the current date
+     *
+     * @param year The current year
+     * @param month The current month
+     * @param dayOfMonth The current dayOfMonth
+     * @param hourOfDay The current hourOfDay
+     * @param minute The current minute
+     */
+    public void setCurrentDate(int year, int month,
+            int dayOfMonth, int hourOfDay, int minute) {
+        setCurrentYear(year);
+        setCurrentMonth(month);
+        setCurrentDay(dayOfMonth);
+        setCurrentHour(hourOfDay);
+        setCurrentMinute(minute);
+    }//实现函数功能——设置当前的时间，参数是各详细的变量
+
+    /**
+     * Get current year
+     *
+     * @return The current year
+     */
+    //下面是得到year、month、day等值
+    public int getCurrentYear() {
+        return mDate.get(Calendar.YEAR);
+    }
+
+    /**
+     * Set current year
+     *
+     * @param year The current year
+     */
+    public void setCurrentYear(int year) {
+        if (!mInitialising && year == getCurrentYear()) {
+            return;
+        }
+        mDate.set(Calendar.YEAR, year);
+        updateDateControl();
+        onDateTimeChanged();
+    }
+
+    /**
+     * Get current month in the year
+     *
+     * @return The current month in the year
+     */
+    public int getCurrentMonth() {
+        return mDate.get(Calendar.MONTH);
+    }
+
+    /**
+     * Set current month in the year
+     *
+     * @param month The month in the year
+     */
+    public void setCurrentMonth(int month) {
+        if (!mInitialising && month == getCurrentMonth()) {
+            return;
+        }
+        mDate.set(Calendar.MONTH, month);
+        updateDateControl();
+        onDateTimeChanged();
+    }
+
+    /**
+     * Get current day of the month
+     *
+     * @return The day of the month
+     */
+    public int getCurrentDay() {
+        return mDate.get(Calendar.DAY_OF_MONTH);
+    }
+
+    /**
+     * Set current day of the month
+     *
+     * @param dayOfMonth The day of the month
+     */
+    public void setCurrentDay(int dayOfMonth) {
+        if (!mInitialising && dayOfMonth == getCurrentDay()) {
+            return;
+        }
+        mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
+        updateDateControl();
+        onDateTimeChanged();
+    }
+
+    /**
+     * Get current hour in 24 hour mode, in the range (0~23)
+     * @return The current hour in 24 hour mode
+     */
+    public int getCurrentHourOfDay() {
+        return mDate.get(Calendar.HOUR_OF_DAY);
+    }
+
+    private int getCurrentHour() {
+        if (mIs24HourView){
+            return getCurrentHourOfDay();
+        } else {
+            int hour = getCurrentHourOfDay();
+            if (hour > HOURS_IN_HALF_DAY) {
+                return hour - HOURS_IN_HALF_DAY;
+            } else {
+                return hour == 0 ? HOURS_IN_HALF_DAY : hour;
+            }
+        }
+    }
+
+    /**
+     * Set current hour in 24 hour mode, in the range (0~23)
+     *
+     * @param hourOfDay
+     */
+    public void setCurrentHour(int hourOfDay) {
+        if (!mInitialising && hourOfDay == getCurrentHourOfDay()) {
+            return;
+        }
+        mDate.set(Calendar.HOUR_OF_DAY, hourOfDay);
+        if (!mIs24HourView) {
+            if (hourOfDay >= HOURS_IN_HALF_DAY) {
+                mIsAm = false;
+                if (hourOfDay > HOURS_IN_HALF_DAY) {
+                    hourOfDay -= HOURS_IN_HALF_DAY;
+                }
+            } else {
+                mIsAm = true;
+                if (hourOfDay == 0) {
+                    hourOfDay = HOURS_IN_HALF_DAY;
+                }
+            }
+            updateAmPmControl();
+        }
+        mHourSpinner.setValue(hourOfDay);
+        onDateTimeChanged();
+    }
+
+    /**
+     * Get currentMinute
+     *
+     * @return The Current Minute
+     */
+    public int getCurrentMinute() {
+        return mDate.get(Calendar.MINUTE);
+    }
+
+    /**
+     * Set current minute
+     */
+    public void setCurrentMinute(int minute) {
+        if (!mInitialising && minute == getCurrentMinute()) {
+            return;
+        }
+        mMinuteSpinner.setValue(minute);
+        mDate.set(Calendar.MINUTE, minute);
+        onDateTimeChanged();
+    }
+
+    /**
+     * @return true if this is in 24 hour view else false.
+     */
+    public boolean is24HourView () {
+        return mIs24HourView;
+    }
+
+    /**
+     * Set whether in 24 hour or AM/PM mode.
+     *
+     * @param is24HourView True for 24 hour mode. False for AM/PM mode.
+     */
+    public void set24HourView(boolean is24HourView) {
+        if (mIs24HourView == is24HourView) {
+            return;
+        }
+        mIs24HourView = is24HourView;
+        mAmPmSpinner.setVisibility(is24HourView ? View.GONE : View.VISIBLE);
+        int hour = getCurrentHourOfDay();
+        updateHourControl();
+        setCurrentHour(hour);
+        updateAmPmControl();
+    }
+
+    private void updateDateControl() {
+        Calendar cal = Calendar.getInstance();
+        cal.setTimeInMillis(mDate.getTimeInMillis());
+        cal.add(Calendar.DAY_OF_YEAR, -DAYS_IN_ALL_WEEK / 2 - 1);
+        mDateSpinner.setDisplayedValues(null);
+        for (int i = 0; i < DAYS_IN_ALL_WEEK; ++i) {
+            cal.add(Calendar.DAY_OF_YEAR, 1);
+            mDateDisplayValues[i] = (String) DateFormat.format("MM.dd EEEE", cal);
+        }
+        mDateSpinner.setDisplayedValues(mDateDisplayValues);
+        mDateSpinner.setValue(DAYS_IN_ALL_WEEK / 2);
+        mDateSpinner.invalidate();
+    }//对于星期几的算法
+
+    private void updateAmPmControl() {
+        if (mIs24HourView) {
+            mAmPmSpinner.setVisibility(View.GONE);
+        } else {
+            int index = mIsAm ? Calendar.AM : Calendar.PM;
+            mAmPmSpinner.setValue(index);
+            mAmPmSpinner.setVisibility(View.VISIBLE);
+        }//对于上下午操作的算法
+    }
+
+    private void updateHourControl() {
+        if (mIs24HourView) {
+            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW);
+            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW);
+        } else {
+            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW);
+            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW);
+        }//对于小时的算法
+    }
+
+    /**
+     * Set the callback that indicates the 'Set' button has been pressed.
+     * @param callback the callback, if null will do nothing
+     */
+    public void setOnDateTimeChangedListener(OnDateTimeChangedListener callback) {
+        mOnDateTimeChangedListener = callback;
+    }
+
+    private void onDateTimeChanged() {
+        if (mOnDateTimeChangedListener != null) {
+            mOnDateTimeChangedListener.onDateTimeChanged(this, getCurrentYear(),
+                    getCurrentMonth(), getCurrentDay(), getCurrentHourOfDay(), getCurrentMinute());
+        }
+    }
+}

DateTimePickerDialog.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import java.util.Calendar;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.DateTimePicker;
+import net.micode.notes.ui.DateTimePicker.OnDateTimeChangedListener;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
+import android.text.format.DateFormat;
+import android.text.format.DateUtils;
+
+public class DateTimePickerDialog extends AlertDialog implements OnClickListener {
+
+    private Calendar mDate = Calendar.getInstance();
+    //创建一个Calendar类型的变量 mDate，方便时间的操作
+    private boolean mIs24HourView;
+    private OnDateTimeSetListener mOnDateTimeSetListener;
+    //声明一个时间日期滚动选择控件 mOnDateTimeSetListener
+    private DateTimePicker mDateTimePicker;
+    //DateTimePicker控件，控件一般用于让用户可以从日期列表中选择单个值。
+    //运行时，单击控件边上的下拉箭头，会显示为两个部分：一个下拉列表，一个用于选择日期的
+    public interface OnDateTimeSetListener {
+        void OnDateTimeSet(AlertDialog dialog, long date);
+    }
+
+    public DateTimePickerDialog(Context context, long date) {
+        //对该界面对话框的实例化
+        super(context);
+        //对数据库的操作
+        mDateTimePicker = new DateTimePicker(context);
+        setView(mDateTimePicker);
+        //添加一个子视图
+        mDateTimePicker.setOnDateTimeChangedListener(new OnDateTimeChangedListener() {
+            public void onDateTimeChanged(DateTimePicker view, int year, int month,
+                    int dayOfMonth, int hourOfDay, int minute) {
+                mDate.set(Calendar.YEAR, year);
+                mDate.set(Calendar.MONTH, month);
+                mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
+                mDate.set(Calendar.HOUR_OF_DAY, hourOfDay);
+                mDate.set(Calendar.MINUTE, minute);
+                //将视图中的各选项设置为系统当前时间
+                updateTitle(mDate.getTimeInMillis());
+            }
+        });
+        mDate.setTimeInMillis(date);
+        //得到系统时间
+        mDate.set(Calendar.SECOND, 0);
+        //将秒数设置为0
+        mDateTimePicker.setCurrentDate(mDate.getTimeInMillis());
+        setButton(context.getString(R.string.datetime_dialog_ok), this);
+        setButton2(context.getString(R.string.datetime_dialog_cancel), (OnClickListener)null);
+        //设置按钮
+        set24HourView(DateFormat.is24HourFormat(this.getContext()));
+        //时间标准化打印
+        updateTitle(mDate.getTimeInMillis());
+    }
+
+    public void set24HourView(boolean is24HourView) {
+        mIs24HourView = is24HourView;
+    }
+
+    public void setOnDateTimeSetListener(OnDateTimeSetListener callBack) {
+        mOnDateTimeSetListener = callBack;
+    }//时间标准化打印
+
+    private void updateTitle(long date) {
+        int flag =
+            DateUtils.FORMAT_SHOW_YEAR |
+            DateUtils.FORMAT_SHOW_DATE |
+            DateUtils.FORMAT_SHOW_TIME;
+        flag |= mIs24HourView ? DateUtils.FORMAT_24HOUR : DateUtils.FORMAT_24HOUR;
+        setTitle(DateUtils.formatDateTime(this.getContext(), date, flag));
+    }//android开发中常见日期管理工具类（API）——DateUtils：按照上下午显示时间
+
+    public void onClick(DialogInterface arg0, int arg1) {
+        if (mOnDateTimeSetListener != null) {
+            mOnDateTimeSetListener.OnDateTimeSet(this, mDate.getTimeInMillis());
+        }
+    }
+//第一个参数arg0是接收到点击事件的对话框
+//第二个参数arg1是该对话框上的按钮
+}

DropdownMenu.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Context;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.widget.Button;
+import android.widget.PopupMenu;
+import android.widget.PopupMenu.OnMenuItemClickListener;
+
+import net.micode.notes.R;
+
+public class DropdownMenu {
+    private Button mButton;
+    private PopupMenu mPopupMenu;
+    //声明一个下拉菜单
+    private Menu mMenu;
+
+    public DropdownMenu(Context context, Button button, int menuId) {
+        mButton = button;
+        mButton.setBackgroundResource(R.drawable.dropdown_icon);
+        //设置这个view的背景
+        mPopupMenu = new PopupMenu(context, mButton);
+        mMenu = mPopupMenu.getMenu();
+        mPopupMenu.getMenuInflater().inflate(menuId, mMenu);
+         //MenuInflater是用来实例化Menu目录下的Menu布局文件
+        //根据ID来确认menu的内容选项
+        mButton.setOnClickListener(new OnClickListener() {
+            public void onClick(View v) {
+                mPopupMenu.show();
+            }
+        });
+    }
+
+    public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
+        if (mPopupMenu != null) {
+            mPopupMenu.setOnMenuItemClickListener(listener);
+        }//设置菜单的监听
+    }
+
+    public MenuItem findItem(int id) {
+        return mMenu.findItem(id);
+    }//对于菜单选项的初始化，根据索引搜索菜单需要的选项
+
+    public void setTitle(CharSequence title) {
+        mButton.setText(title);
+    }//布局文件，设置标题
+}

FoldersListAdapter.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.CursorAdapter;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+
+
+public class FoldersListAdapter extends CursorAdapter {
+    //CursorAdapter是Cursor和ListView的接口
+	//FoldersListAdapter继承了CursorAdapter的类
+	//主要作用是便签数据库和用户的交互
+	//这里就是用folder（文件夹）的形式展现给用户
+    public static final String [] PROJECTION = {
+        NoteColumns.ID,
+        NoteColumns.SNIPPET
+    };//调用数据库中便签的ID和片段
+
+    public static final int ID_COLUMN   = 0;
+    public static final int NAME_COLUMN = 1;
+
+    public FoldersListAdapter(Context context, Cursor c) {
+        super(context, c);
+        // TODO Auto-generated constructor stub
+    }//数据库操作
+
+    @Override
+    public View newView(Context context, Cursor cursor, ViewGroup parent) {
+        //ViewGroup是容器
+        return new FolderListItem(context);
+    }//创建一个文件夹，对于各文件夹中子标签的初始化
+
+    @Override
+    public void bindView(View view, Context context, Cursor cursor) {
+        if (view instanceof FolderListItem) {
+            String folderName = (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
+                    .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+            ((FolderListItem) view).bind(folderName);
+        }
+    }//将各个布局文件绑定起来
+
+    public String getFolderName(Context context, int position) {
+        Cursor cursor = (Cursor) getItem(position);
+        return (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
+                .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+    }//根据数据库中标签的ID得到标签的各项内容
+
+    private class FolderListItem extends LinearLayout {
+        private TextView mName;
+
+        public FolderListItem(Context context) {
+            super(context);
+            //操作数据库
+            inflate(context, R.layout.folder_list_item, this);
+            // //根据布局文件的名字等信息将其找出来
+            mName = (TextView) findViewById(R.id.tv_folder_name);
+        }
+
+        public void bind(String name) {
+            mName.setText(name);
+        }
+    }
+
+}

GTaskASyncTask.java

@@ -0,0 +1,129 @@
+
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+/*异步操作类，实现GTask的异步操作过程
+ * 主要方法：
+ * private void showNotification(int tickerId, String content) 向用户提示当前同步的状态，是一个用于交互的方法
+ * protected Integer doInBackground(Void... unused) 此方法在后台线程执行，完成任务的主要工作，通常需要较长的时间
+ * protected void onProgressUpdate(String... progress)  可以使用进度条增加用户体验度。 此方法在主线程执行，用于显示任务执行的进度。
+ * protected void onPostExecute(Integer result)  相当于Handler 处理UI的方式，在这里面可以使用在doInBackground 得到的结果处理操作UI
+ */
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.os.AsyncTask;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesListActivity;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+
+public class GTaskASyncTask extends AsyncTask<Void, String, Integer> {
+
+    private static int GTASK_SYNC_NOTIFICATION_ID = 5234235;
+
+    public interface OnCompleteListener {
+        void onComplete();
+    }
+
+    private Context mContext;
+
+    private NotificationManager mNotifiManager;
+
+    private GTaskManager mTaskManager;
+
+    private OnCompleteListener mOnCompleteListener;
+
+    public GTaskASyncTask(Context context, OnCompleteListener listener) {
+        mContext = context;
+        mOnCompleteListener = listener;
+        mNotifiManager = (NotificationManager) mContext
+                .getSystemService(Context.NOTIFICATION_SERVICE);
+        mTaskManager = GTaskManager.getInstance();
+    }
+
+    public void cancelSync() {
+        mTaskManager.cancelSync();
+    }
+
+    public void publishProgess(String message) {/// 发布进度单位，系统将会调用onProgressUpdate()方法更新这些值
+        publishProgress(new String[] {
+            message
+        });
+    }
+
+    private void showNotification(int tickerId, String content) {
+        Notification notification = new Notification(R.drawable.notification, mContext
+                .getString(tickerId), System.currentTimeMillis());
+        notification.defaults = Notification.DEFAULT_LIGHTS;// 调用系统自带灯光
+        notification.flags = Notification.FLAG_AUTO_CANCEL; // 点击清除按钮或点击通知后会自动消失
+        PendingIntent pendingIntent; //一个描述了想要启动一个Activity、Broadcast或是Service的意图
+        if (tickerId != R.string.ticker_success) {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, new Intent(mContext,
+                    NotesPreferenceActivity.class), 0);//如果同步不成功，那么从系统取得一个用于启动一个NotesPreferenceActivity的PendingIntent对象
+
+        } else {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, new Intent(mContext,
+                    NotesListActivity.class), 0); //如果同步成功，那么从系统取得一个用于启动一个NotesListActivity的PendingIntent对象
+        }
+        notification.setLatestEventInfo(mContext, mContext.getString(R.string.app_name), content,
+                pendingIntent);
+        mNotifiManager.notify(GTASK_SYNC_NOTIFICATION_ID, notification);//通过NotificationManager对象的notify（）方法来执行一个notification的消息
+    }
+
+    @Override
+    protected Integer doInBackground(Void... unused) {
+        publishProgess(mContext.getString(R.string.sync_progress_login, NotesPreferenceActivity
+                .getSyncAccountName(mContext)));//利用getString,将把 NotesPreferenceActivity.getSyncAccountName(mContext))的字符串内容传进sync_progress_login中
+        return mTaskManager.sync(mContext, this); //进行后台同步具体操作
+    }
+
+    @Override
+    protected void onProgressUpdate(String... progress) {
+        showNotification(R.string.ticker_syncing, progress[0]);
+        if (mContext instanceof GTaskSyncService) {//instanceof 判断mContext是否是GTaskSyncService的实例
+            ((GTaskSyncService) mContext).sendBroadcast(progress[0]);
+        }
+    }
+
+    @Override
+    protected void onPostExecute(Integer result) {//用于在执行完后台任务后更新UI,显示结果 
+        if (result == GTaskManager.STATE_SUCCESS) {
+            showNotification(R.string.ticker_success, mContext.getString(
+                    R.string.success_sync_account, mTaskManager.getSyncAccount()));
+            NotesPreferenceActivity.setLastSyncTime(mContext, System.currentTimeMillis());//设置最新同步的时间
+        } else if (result == GTaskManager.STATE_NETWORK_ERROR) {
+            showNotification(R.string.ticker_fail, mContext.getString(R.string.error_sync_network));
+        } else if (result == GTaskManager.STATE_INTERNAL_ERROR) {
+            showNotification(R.string.ticker_fail, mContext.getString(R.string.error_sync_internal));
+        } else if (result == GTaskManager.STATE_SYNC_CANCELLED) {
+            showNotification(R.string.ticker_cancel, mContext
+                    .getString(R.string.error_sync_cancelled));
+        }//几种不同情况下的结果显示
+        if (mOnCompleteListener != null) {
+            new Thread(new Runnable() {//这里好像是方法内的一个线程
+
+                public void run() {//完成后的操作，使用onComplete()将所有值都重新初始化，相当于完成一次操作
+                    mOnCompleteListener.onComplete();
+                }
+            }).start();
+        }
+    }
+}

GTaskClient.java

@@ -0,0 +1,649 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.accounts.AccountManagerFuture;
+import android.app.Activity;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.gtask.data.Node;
+import net.micode.notes.gtask.data.Task;
+import net.micode.notes.gtask.data.TaskList;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.gtask.exception.NetworkFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.ClientProtocolException;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.cookie.Cookie;
+import org.apache.http.impl.client.BasicCookieStore;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.params.BasicHttpParams;
+import org.apache.http.params.HttpConnectionParams;
+import org.apache.http.params.HttpParams;
+import org.apache.http.params.HttpProtocolParams;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.Inflater;
+import java.util.zip.InflaterInputStream;
+/*
+ * 主要功能：实现GTASK的登录操作，进行GTASK任务的创建，创建任务列表，从网络上获取任务和任务列表的内容
+ * 主要使用类或技术：accountManager JSONObject HttpParams authToken Gid
+ */ 
+public class GTaskClient {
+    private static final String TAG = GTaskClient.class.getSimpleName();
+
+    private static final String GTASK_URL = "https://mail.google.com/tasks/";//这个是指定的URL
+
+    private static final String GTASK_GET_URL = "https://mail.google.com/tasks/ig";
+
+    private static final String GTASK_POST_URL = "https://mail.google.com/tasks/r/ig";
+
+    private static GTaskClient mInstance = null;
+
+    private DefaultHttpClient mHttpClient;
+
+    private String mGetUrl;
+
+    private String mPostUrl;
+
+    private long mClientVersion;
+
+    private boolean mLoggedin;
+
+    private long mLastLoginTime;
+
+    private int mActionId;
+
+    private Account mAccount;
+
+    private JSONArray mUpdateArray;
+
+    private GTaskClient() {
+        mHttpClient = null;
+        mGetUrl = GTASK_GET_URL;
+        mPostUrl = GTASK_POST_URL;
+        mClientVersion = -1;
+        mLoggedin = false;
+        mLastLoginTime = 0;
+        mActionId = 1;
+        mAccount = null;
+        mUpdateArray = null;
+    }
+/*用来获取的实例化对象
+     * 使用 getInstance()
+     * 返回mInstance这个实例化对象
+     */
+    public static synchronized GTaskClient getInstance() {
+        if (mInstance == null) {
+            mInstance = new GTaskClient();
+        }
+        return mInstance;
+    }
+/*用来实现登录操作的函数，传入的参数是一个Activity
+     * 设置登录操作限制时间，如果超时则需要重新登录
+     * 有两种登录方式，使用用户自己的URL登录或者使用谷歌官方的URL登录
+     * 返回true或者false，即最后是否登陆成功
+     */
+    public boolean login(Activity activity) {
+        // we suppose that the cookie would expire after 5 minutes
+        // then we need to re-login
+        //判断距离最后一次登录操作是否超过5分钟
+        final long interval = 1000 * 60 * 5;
+        if (mLastLoginTime + interval < System.currentTimeMillis()) {
+            mLoggedin = false;
+        }
+
+        // need to re-login after account switch  重新登录操作
+        if (mLoggedin
+                && !TextUtils.equals(getSyncAccount().name, NotesPreferenceActivity
+                        .getSyncAccountName(activity))) {
+            mLoggedin = false;
+        }
+ //如果没超过时间，则不需要重新登录
+        if (mLoggedin) {
+            Log.d(TAG, "already logged in");
+            return true;
+        }
+
+        mLastLoginTime = System.currentTimeMillis();//更新最后登录时间，改为系统当前的时间
+        String authToken = loginGoogleAccount(activity, false);//判断是否登录到谷歌账户
+        if (authToken == null) {
+            Log.e(TAG, "login google account failed");
+            return false;
+        }
+
+        // login with custom domain if necessary
+        //尝试使用用户自己的域名登录
+        if (!(mAccount.name.toLowerCase().endsWith("gmail.com") || mAccount.name.toLowerCase()//将用户账号名改为统一格式（小写）后判断是否为一个谷歌账号地址
+                .endsWith("googlemail.com"))) {
+            StringBuilder url = new StringBuilder(GTASK_URL).append("a/");
+            int index = mAccount.name.indexOf('@') + 1;
+            String suffix = mAccount.name.substring(index);
+            url.append(suffix + "/");
+            mGetUrl = url.toString() + "ig";//设置用户对应的getUrl
+            mPostUrl = url.toString() + "r/ig"; //设置用户对应的postUrl
+
+            if (tryToLoginGtask(activity, authToken)) {
+                mLoggedin = true;
+            }
+        }
+
+        // try to login with google official url
+        //如果用户账户无法登录，则使用谷歌官方的URI进行登录
+        if (!mLoggedin) {
+            mGetUrl = GTASK_GET_URL;
+            mPostUrl = GTASK_POST_URL;
+            if (!tryToLoginGtask(activity, authToken)) {
+                return false;
+            }
+        }
+
+        mLoggedin = true;
+        return true;
+    }
+/*具体实现登录谷歌账户的方法
+     * 使用令牌机制
+     * 使用AccountManager来管理注册账号
+     * 返回值是账号的令牌
+     */
+    private String loginGoogleAccount(Activity activity, boolean invalidateToken) {
+        String authToken; //令牌，是登录操作保证安全性的一个方法
+        AccountManager accountManager = AccountManager.get(activity);//AccountManager这个类给用户提供了集中注册账号的接口
+        Account[] accounts = accountManager.getAccountsByType("com.google");//获取全部以com.google结尾的account
+
+        if (accounts.length == 0) {
+            Log.e(TAG, "there is no available google account");
+            return null;
+        }
+
+        String accountName = NotesPreferenceActivity.getSyncAccountName(activity);
+        Account account = null;
+        //遍历获得的accounts信息，寻找已经记录过的账户信息
+        for (Account a : accounts) {
+            if (a.name.equals(accountName)) {
+                account = a;
+                break;
+            }
+        }
+        if (account != null) {
+            mAccount = account;
+        } else {
+            Log.e(TAG, "unable to get an account with the same name in the settings");
+            return null;
+        }
+
+        // get the token now
+         //获取选中账号的令牌
+        AccountManagerFuture<Bundle> accountManagerFuture = accountManager.getAuthToken(account,
+                "goanna_mobile", null, activity, null, null);
+        try {
+            Bundle authTokenBundle = accountManagerFuture.getResult();
+            authToken = authTokenBundle.getString(AccountManager.KEY_AUTHTOKEN);
+             //如果是invalidateToken，那么需要调用invalidateAuthToken(String, String)方法废除这个无效token
+            if (invalidateToken) {
+                accountManager.invalidateAuthToken("com.google", authToken);
+                loginGoogleAccount(activity, false);
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "get auth token failed");
+            authToken = null;
+        }
+
+        return authToken;
+    }
+//尝试登陆Gtask，这只是一个预先判断令牌是否是有效以及是否能登上GTask的方法,而不是具体实现登陆的方法
+    private boolean tryToLoginGtask(Activity activity, String authToken) {
+        if (!loginGtask(authToken)) {
+            // maybe the auth token is out of date, now let's invalidate the
+            // token and try again
+            //删除过一个无效的authToken，申请一个新的后再次尝试登陆
+            authToken = loginGoogleAccount(activity, true);
+            if (authToken == null) {
+                Log.e(TAG, "login google account failed");
+                return false;
+            }
+
+            if (!loginGtask(authToken)) {
+                Log.e(TAG, "login gtask failed");
+                return false;
+            }
+        }
+        return true;
+    }
+//实现登录GTask的具体操作
+    private boolean loginGtask(String authToken) {
+        int timeoutConnection = 10000;
+        int timeoutSocket = 15000;//socket是一种通信连接实现数据的交换的端口
+        HttpParams httpParameters = new BasicHttpParams();//实例化一个新的HTTP参数类
+        HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);//设置连接超时时间
+        HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);//设置端口超时时间
+        mHttpClient = new DefaultHttpClient(httpParameters);
+        BasicCookieStore localBasicCookieStore = new BasicCookieStore();//设置本地cookie
+        mHttpClient.setCookieStore(localBasicCookieStore);
+        HttpProtocolParams.setUseExpectContinue(mHttpClient.getParams(), false);
+
+        // login gtask
+        try {
+            String loginUrl = mGetUrl + "?auth=" + authToken;//设置登陆的url
+            HttpGet httpGet = new HttpGet(loginUrl);//通过登录的url实例化网页上资源的查找
+            HttpResponse response = null;
+            response = mHttpClient.execute(httpGet);
+
+            // get the cookie now
+            //获取CookieStore里存放的cookie，如果存有“GTL”，则说明有验证成功的有效的cookie
+            List<Cookie> cookies = mHttpClient.getCookieStore().getCookies();
+            boolean hasAuthCookie = false;
+            for (Cookie cookie : cookies) {
+                if (cookie.getName().contains("GTL")) {
+                    hasAuthCookie = true;
+                }
+            }
+            if (!hasAuthCookie) {
+                Log.w(TAG, "it seems that there is no auth cookie");
+            }
+
+            // get the client version
+            //获取client的内容，具体操作是在返回的Content中截取从_setup（开始到）}</script>中间的字符串内容，也就是gtask_url的内容
+            String resString = getResponseContent(response.getEntity());
+            String jsBegin = "_setup(";
+            String jsEnd = ")}</script>";
+            int begin = resString.indexOf(jsBegin);
+            int end = resString.lastIndexOf(jsEnd);
+            String jsString = null;
+            if (begin != -1 && end != -1 && begin < end) {
+                jsString = resString.substring(begin + jsBegin.length(), end);
+            }
+            JSONObject js = new JSONObject(jsString);
+            mClientVersion = js.getLong("v");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return false;
+        } catch (Exception e) {
+            // simply catch all exceptions
+            Log.e(TAG, "httpget gtask_url failed");
+            return false;
+        }
+
+        return true;
+    }
+
+    private int getActionId() {
+        return mActionId++;
+    }
+/**实例化创建一个用于向网络传输数据的对象
+ * 使用HttpPost类，
+ * 返回一个httpPost实例化对象，但里面还没有内容
+ */
+    private HttpPost createHttpPost() {
+        HttpPost httpPost = new HttpPost(mPostUrl);
+        httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
+        httpPost.setHeader("AT", "1");
+        return httpPost;
+    }
+/**通过URL获取响应后返回的数据，也就是网络上的数据和资源
+ * 使用getContentEncoding（）获取网络上的资源和数据
+ * 返回值就是获取到的资源
+ */
+    private String getResponseContent(HttpEntity entity) throws IOException {
+        String contentEncoding = null;
+        if (entity.getContentEncoding() != null) {//通过url得到HttpEntity对象，如果不为空则使用getContent（）方法创建一个流将数据从网络都过来
+            contentEncoding = entity.getContentEncoding().getValue();
+            Log.d(TAG, "encoding: " + contentEncoding);
+        }
+
+        InputStream input = entity.getContent();
+        if (contentEncoding != null && contentEncoding.equalsIgnoreCase("gzip")) {//gzip是使用deflate进行压缩数据的另一个压缩库
+            input = new GZIPInputStream(entity.getContent());
+        } else if (contentEncoding != null && contentEncoding.equalsIgnoreCase("deflate")) {//deflate是一个无专利的压缩算法，它可以实现无损数据压缩
+            Inflater inflater = new Inflater(true);
+            input = new InflaterInputStream(entity.getContent(), inflater);
+        }
+
+        try {
+            InputStreamReader isr = new InputStreamReader(input);
+            BufferedReader br = new BufferedReader(isr);//是一个包装类，它可以包装字符流，将字符流放入缓存中，先把字符读到缓存里，到缓存满了的时候，再读入内存，是为了提供读的效率而设计的
+            StringBuilder sb = new StringBuilder();
+
+            while (true) {
+                String buff = br.readLine();
+                if (buff == null) {
+                    return sb.toString();
+                }
+                sb = sb.append(buff);
+            }
+        } finally {
+            input.close();
+        }
+    }
+/**
+ * 通过JSON发送请求
+ * 请求的具体内容在json的实例化对象js中然后传入
+ * 利用UrlEncodedFormEntity entity和httpPost.setEntity(entity)方法把js中的内容放置到httpPost中
+ * 执行请求后使用getResponseContent方法得到返回的数据和资源
+ * 将资源再次放入json后返回
+ */
+    private JSONObject postRequest(JSONObject js) throws NetworkFailureException {
+        if (!mLoggedin) {//未登录
+            Log.e(TAG, "please login first");
+            throw new ActionFailureException("not logged in");
+        }
+//实例化一个httpPost的对象用来向服务器传输数据，在这里就是发送请求，而请求的内容在js里
+        HttpPost httpPost = createHttpPost();
+        try {
+            LinkedList<BasicNameValuePair> list = new LinkedList<BasicNameValuePair>();
+            list.add(new BasicNameValuePair("r", js.toString()));
+            UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, "UTF-8");//UrlEncodedFormEntity（）的形式比较单一，是普通的键值对
+            httpPost.setEntity(entity);
+
+            // execute the post
+            //执行这个请求
+            HttpResponse response = mHttpClient.execute(httpPost);
+            String jsString = getResponseContent(response.getEntity());
+            return new JSONObject(jsString);
+
+        } catch (ClientProtocolException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("postRequest failed");
+        } catch (IOException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("postRequest failed");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("unable to convert response content to jsonobject");
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("error occurs when posting request");
+        }
+    }
+/**创建单个任务
+ * 传入参数是一个.gtask.data.Task包里Task类的对象
+ * 利用json获取Task里的内容，并且创建相应的jsPost
+ * 利用postRequest得到任务的返回信息
+ * 利用task.setGid设置task的new_ID
+ */
+    public void createTask(Task task) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            actionList.put(task.getCreateAction(getActionId()));
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            // post
+            JSONObject jsResponse = postRequest(jsPost);
+            JSONObject jsResult = (JSONObject) jsResponse.getJSONArray(
+                    GTaskStringUtils.GTASK_JSON_RESULTS).get(0);
+            task.setGid(jsResult.getString(GTaskStringUtils.GTASK_JSON_NEW_ID));
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("create task: handing jsonobject failed");
+        }
+    }
+/**创建一个任务列表，与createTask几乎一样，区别就是最后设置的是tasklist的gid */
+    public void createTaskList(TaskList tasklist) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            actionList.put(tasklist.getCreateAction(getActionId()));
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            // post
+            JSONObject jsResponse = postRequest(jsPost);
+            JSONObject jsResult = (JSONObject) jsResponse.getJSONArray(
+                    GTaskStringUtils.GTASK_JSON_RESULTS).get(0);
+            tasklist.setGid(jsResult.getString(GTaskStringUtils.GTASK_JSON_NEW_ID));
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("create tasklist: handing jsonobject failed");
+        }
+    }
+/**
+ * 同步更新操作
+ * 使用JSONObject进行数据存储，使用jsPost.put,Put的信息包括UpdateArray和ClientVersion
+ * 使用postRequest发送这个jspost，进行处理
+ */
+    public void commitUpdate() throws NetworkFailureException {
+        if (mUpdateArray != null) {
+            try {
+                JSONObject jsPost = new JSONObject();
+
+                // action_list
+                jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, mUpdateArray);
+
+                // client_version
+                jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+                postRequest(jsPost);
+                mUpdateArray = null;
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("commit update: handing jsonobject failed");
+            }
+        }
+    }
+/**
+ * 添加更新的事项
+ * 调用commitUpdate（）实现
+ */
+    public void addUpdateNode(Node node) throws NetworkFailureException {
+        if (node != null) {
+            // too many update items may result in an error
+            // set max to 10 items
+            if (mUpdateArray != null && mUpdateArray.length() > 10) {
+                commitUpdate();
+            }
+
+            if (mUpdateArray == null)
+                mUpdateArray = new JSONArray();
+            mUpdateArray.put(node.getUpdateAction(getActionId()));
+        }
+    }
+/**
+ * 移动task，比如讲task移动到不同的task列表中去
+ * 通过getGid获取task所属列表的gid
+ * 通过JSONObject.put（String name，Object value）函数设置移动后的task的相关属性，从而达到移动的目的
+ * 最后还是通过postRequest进行更新后的发送
+ */
+    public void moveTask(Task task, TaskList preParent, TaskList curParent)
+            throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+            JSONObject action = new JSONObject();
+
+            // action_list
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_MOVE);
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, getActionId());
+            action.put(GTaskStringUtils.GTASK_JSON_ID, task.getGid());
+            if (preParent == curParent && task.getPriorSibling() != null) {
+                // put prioring_sibing_id only if moving within the tasklist and
+                // it is not the first one
+                //设置优先级ID，只有当移动是发生在文件中
+                action.put(GTaskStringUtils.GTASK_JSON_PRIOR_SIBLING_ID, task.getPriorSibling());
+            }
+            action.put(GTaskStringUtils.GTASK_JSON_SOURCE_LIST, preParent.getGid());//设置移动前所属列表
+            action.put(GTaskStringUtils.GTASK_JSON_DEST_PARENT, curParent.getGid());//设置当前所属列表
+            if (preParent != curParent) {
+                // put the dest_list only if moving between tasklists
+                action.put(GTaskStringUtils.GTASK_JSON_DEST_LIST, curParent.getGid());
+            }
+            actionList.put(action);
+            //最后将ACTION_LIST加入到jsPost中
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            postRequest(jsPost);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("move task: handing jsonobject failed");
+        }
+    }
+/**
+ * 删除操作节点
+ * 还是利用JSON
+ * 删除过后使用postRequest发送删除后的结果
+ */
+    public void deleteNode(Node node) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            node.setDeleted(true);
+            actionList.put(node.getUpdateAction(getActionId()));//这里会获取到删除操作的ID，加入到actionLiast中
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            postRequest(jsPost);
+            mUpdateArray = null;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("delete node: handing jsonobject failed");
+        }
+    }
+/**
+ * 获取任务列表
+ * 首先通过GetURI使用getResponseContent从网上获取数据
+ * 然后筛选出"_setup("到)}</script>的部分，并且从中获取GTASK_JSON_LISTS的内容返回
+ */
+    public JSONArray getTaskLists() throws NetworkFailureException {
+        if (!mLoggedin) {
+            Log.e(TAG, "please login first");
+            throw new ActionFailureException("not logged in");
+        }
+
+        try {
+            HttpGet httpGet = new HttpGet(mGetUrl);
+            HttpResponse response = null;
+            response = mHttpClient.execute(httpGet);
+
+            // get the task list
+            //筛选工作，把筛选出的字符串放入jsString
+            String resString = getResponseContent(response.getEntity());
+            String jsBegin = "_setup(";
+            String jsEnd = ")}</script>";
+            int begin = resString.indexOf(jsBegin);
+            int end = resString.lastIndexOf(jsEnd);
+            String jsString = null;
+            if (begin != -1 && end != -1 && begin < end) {
+                jsString = resString.substring(begin + jsBegin.length(), end);
+            }
+            JSONObject js = new JSONObject(jsString);
+            //获取GTASK_JSON_LISTS
+            return js.getJSONObject("t").getJSONArray(GTaskStringUtils.GTASK_JSON_LISTS);
+        } catch (ClientProtocolException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("gettasklists: httpget failed");
+        } catch (IOException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("gettasklists: httpget failed");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("get task lists: handing jasonobject failed");
+        }
+    }
+/**通过传入的TASKList的gid，从网络上获取相应属于这个任务列表的任务 */
+    public JSONArray getTaskList(String listGid) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+            JSONObject action = new JSONObject();
+
+            // action_list
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_GETALL);
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, getActionId());
+            action.put(GTaskStringUtils.GTASK_JSON_LIST_ID, listGid);//这里设置为传入的listGid
+            action.put(GTaskStringUtils.GTASK_JSON_GET_DELETED, false);
+            actionList.put(action);
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            JSONObject jsResponse = postRequest(jsPost);
+            return jsResponse.getJSONArray(GTaskStringUtils.GTASK_JSON_TASKS);
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("get task list: handing jsonobject failed");
+        }
+    }
+
+    public Account getSyncAccount() {
+        return mAccount;
+    }
+//重置更新的内容
+    public void resetUpdateArray() {
+        mUpdateArray = null;
+    }
+}

GTaskManager.java

@@ -0,0 +1,824 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.app.Activity;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.data.MetaData;
+import net.micode.notes.gtask.data.Node;
+import net.micode.notes.gtask.data.SqlNote;
+import net.micode.notes.gtask.data.Task;
+import net.micode.notes.gtask.data.TaskList;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.gtask.exception.NetworkFailureException;
+import net.micode.notes.tool.DataUtils;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+
+
+public class GTaskManager {
+    private static final String TAG = GTaskManager.class.getSimpleName();
+
+    public static final int STATE_SUCCESS = 0;
+
+    public static final int STATE_NETWORK_ERROR = 1;
+
+    public static final int STATE_INTERNAL_ERROR = 2;
+
+    public static final int STATE_SYNC_IN_PROGRESS = 3;
+
+    public static final int STATE_SYNC_CANCELLED = 4;
+
+    private static GTaskManager mInstance = null;
+
+    private Activity mActivity;
+
+    private Context mContext;
+
+    private ContentResolver mContentResolver;
+
+    private boolean mSyncing;
+
+    private boolean mCancelled;
+
+    private HashMap<String, TaskList> mGTaskListHashMap;
+
+    private HashMap<String, Node> mGTaskHashMap;
+
+    private HashMap<String, MetaData> mMetaHashMap;
+
+    private TaskList mMetaList;
+
+    private HashSet<Long> mLocalDeleteIdMap;
+
+    private HashMap<String, Long> mGidToNid;
+
+    private HashMap<Long, String> mNidToGid;
+
+    private GTaskManager() {//对象初始化函数
+        mSyncing = false;//正在同步，flase代表未执行
+        mCancelled = false;//全局标识，flase代表可以执行
+        mGTaskListHashMap = new HashMap<String, TaskList>();//<>代表Java的泛型，就是创建一个用类型作为参数的类
+        mGTaskHashMap = new HashMap<String, Node>();
+        mMetaHashMap = new HashMap<String, MetaData>();
+        mMetaList = null;
+        mLocalDeleteIdMap = new HashSet<Long>();
+        mGidToNid = new HashMap<String, Long>();
+        mNidToGid = new HashMap<Long, String>();//通过hashmap散列表建立映射
+    }
+/**
+ * 包含关键字synchronized，语言级同步，指明该函数可能运行在多线程的环境下
+ * 实现功能：类初始化函数
+ */
+    public static synchronized GTaskManager getInstance() {//可能运行在多线程环境下，使用语言级同步--synchronized
+        if (mInstance == null) {
+            mInstance = new GTaskManager();
+        }
+        return mInstance;
+    }
+/**
+ * 包含关键字synchronized，语言级同步，指明该函数可能运行在多线程的环境下
+ */
+    public synchronized void setActivityContext(Activity activity) {
+        // used for getting authtoken
+        mActivity = activity;
+    }
+/**实现功能：实现了本地同步操作和远端同步操作 
+ * context---获取上下文
+ * asyncTask---用于同步的异步操作类
+*/
+    public int sync(Context context, GTaskASyncTask asyncTask) {//核心函数
+        if (mSyncing) {
+            Log.d(TAG, "Sync is in progress");//创建日志文件（调试信息），debug
+            return STATE_SYNC_IN_PROGRESS;
+        }
+        mContext = context;
+        mContentResolver = mContext.getContentResolver();
+        mSyncing = true;
+        mCancelled = false;
+        mGTaskListHashMap.clear();
+        mGTaskHashMap.clear();
+        mMetaHashMap.clear();
+        mLocalDeleteIdMap.clear();
+        mGidToNid.clear();
+        mNidToGid.clear();
+
+        try {
+            GTaskClient client = GTaskClient.getInstance();//getInstance即为创建一个实例，client---客户机
+            client.resetUpdateArray();//JSONArray类型，reset即置为NULL
+
+            // login google task
+            if (!mCancelled) {
+                if (!client.login(mActivity)) {
+                    throw new NetworkFailureException("login google task failed");
+                }
+            }
+
+            // get the task list from google
+            asyncTask.publishProgess(mContext.getString(R.string.sync_progress_init_list));
+            initGTaskList();//获取Google上的JSONtasklist转为本地TaskList
+
+            // do content sync work
+            asyncTask.publishProgess(mContext.getString(R.string.sync_progress_syncing));
+            syncContent();
+        } catch (NetworkFailureException e) {//分为两种异常，此类异常为网络异常
+            Log.e(TAG, e.toString());//创建日志文件（调试信息），error
+            return STATE_NETWORK_ERROR;
+        } catch (ActionFailureException e) {//此类异常为操作异常
+            Log.e(TAG, e.toString());
+            return STATE_INTERNAL_ERROR;
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return STATE_INTERNAL_ERROR;
+        } finally {
+            mGTaskListHashMap.clear();
+            mGTaskHashMap.clear();
+            mMetaHashMap.clear();
+            mLocalDeleteIdMap.clear();
+            mGidToNid.clear();
+            mNidToGid.clear();
+            mSyncing = false;
+        }
+
+        return mCancelled ? STATE_SYNC_CANCELLED : STATE_SUCCESS;
+    }
+/**
+ * 实现功能：初始化GtaskList，获取Google上的JSONtasklist转为本地TaskList
+ * 获得的的数据存储在mMetaList，mGTaskListHashMap,mGTaskHashMap
+ */
+    private void initGTaskList() throws NetworkFailureException {
+        if (mCancelled)
+            return;
+        GTaskClient client = GTaskClient.getInstance();//getInstance即为创建一个实例，client应指远端客户机
+        try {
+            //Json对象是Name Value对（及子元素）的无序集合，相当于一个Map对象，JsonObject类是bantouyan-json库对Json对象的抽象，提供操纵Json对象的各种方法
+            //其格式为{"key1":value1,"key2",value2....};key必须是字符串
+            //因为ajax请求不刷新页面，但配合js可以实现局部刷新，因此json常常被用来作为异步请求的返回对象使用
+            JSONArray jsTaskLists = client.getTaskLists();
+
+            // init meta list first
+            mMetaList = null;//TaskList类型
+            for (int i = 0; i < jsTaskLists.length(); i++) {
+                JSONObject object = jsTaskLists.getJSONObject(i);//JSONObject与JSONArray一个为对象，一个为数组，此处取出单个JASONObject
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                String name = object.getString(GTaskStringUtils.GTASK_JSON_NAME);
+
+                if (name
+                        .equals(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_META)) {
+                    mMetaList = new TaskList();//MetaList意为元表，Tasklist类型，此处为初始化
+                    mMetaList.setContentByRemoteJSON(object);//将JSON中部分数据复制到自己定义的对象中相对应的数据：name->mname
+
+                    // load meta data
+                    JSONArray jsMetas = client.getTaskList(gid);
+                    for (int j = 0; j < jsMetas.length(); j++) {
+                        object = (JSONObject) jsMetas.getJSONObject(j);
+                        MetaData metaData = new MetaData();//继承自Node
+                        metaData.setContentByRemoteJSON(object);
+                        if (metaData.isWorthSaving()) {//if not worth to save，metadate将不加入mMetaList
+                            mMetaList.addChildTask(metaData);
+                            if (metaData.getGid() != null) {
+                                mMetaHashMap.put(metaData.getRelatedGid(), metaData);
+                            }
+                        }
+                    }
+                }
+            }
+
+            // create meta list if not existed
+            if (mMetaList == null) {
+                mMetaList = new TaskList();
+                mMetaList.setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                        + GTaskStringUtils.FOLDER_META);
+                GTaskClient.getInstance().createTaskList(mMetaList);
+            }
+
+            // init task list
+            for (int i = 0; i < jsTaskLists.length(); i++) {
+                JSONObject object = jsTaskLists.getJSONObject(i);
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);//通过getString函数传入本地某个标志数据的名称，获取其在远端的名称
+                String name = object.getString(GTaskStringUtils.GTASK_JSON_NAME);
+
+                if (name.startsWith(GTaskStringUtils.MIUI_FOLDER_PREFFIX)
+                        && !name.equals(GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                                + GTaskStringUtils.FOLDER_META)) {
+                    TaskList tasklist = new TaskList();//继承自Node
+                    tasklist.setContentByRemoteJSON(object);
+                    mGTaskListHashMap.put(gid, tasklist);
+                    mGTaskHashMap.put(gid, tasklist);
+
+                    // load tasks
+                    JSONArray jsTasks = client.getTaskList(gid);
+                    for (int j = 0; j < jsTasks.length(); j++) {
+                        object = (JSONObject) jsTasks.getJSONObject(j);
+                        gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                        Task task = new Task();
+                        task.setContentByRemoteJSON(object);
+                        if (task.isWorthSaving()) {
+                            task.setMetaInfo(mMetaHashMap.get(gid));
+                            tasklist.addChildTask(task);
+                            mGTaskHashMap.put(gid, task);
+                        }
+                    }
+                }
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("initGTaskList: handing JSONObject failed");
+        }
+    }
+/**
+ * 实现功能：本地内容同步操作
+ */
+    private void syncContent() throws NetworkFailureException {//本地内容同步操作
+        int syncType;
+        Cursor c = null;//数据库指针
+        String gid;
+        Node node;//Node包含Sync_Action的不同类型
+
+        mLocalDeleteIdMap.clear();//HashSet<Long>类型
+
+        if (mCancelled) {
+            return;
+        }
+
+        // for local deleted note
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type<>? AND parent_id=?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, null);
+            if (c != null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        doContentSync(Node.SYNC_ACTION_DEL_REMOTE, node, c);
+                    }
+
+                    mLocalDeleteIdMap.add(c.getLong(SqlNote.ID_COLUMN));
+                }
+            } else {
+                Log.w(TAG, "failed to query trash folder");
+            }
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // sync folder first
+        syncFolder();
+
+        // for note existing in database
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type=? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_NOTE), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c != null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, c.getLong(SqlNote.ID_COLUMN));//通过hashmap建立联系
+                        mNidToGid.put(c.getLong(SqlNote.ID_COLUMN), gid);//通过hashmap建立联系
+                        syncType = node.getSyncAction(c);
+                    } else {
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {
+                            // local add
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;
+                        } else {
+                            // remote delete
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;
+                        }
+                    }
+                    doContentSync(syncType, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query existing note in database");
+            }
+
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // go through remaining items
+        Iterator<Map.Entry<String, Node>> iter = mGTaskHashMap.entrySet().iterator();//iterator迭代器
+        while (iter.hasNext()) {
+            Map.Entry<String, Node> entry = iter.next();
+            node = entry.getValue();
+            doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);
+        }
+
+        // mCancelled can be set by another thread, so we neet to check one by
+        // one
+        // clear local delete table
+        if (!mCancelled) {
+            if (!DataUtils.batchDeleteNotes(mContentResolver, mLocalDeleteIdMap)) {
+                throw new ActionFailureException("failed to batch-delete local deleted notes");
+            }
+        }
+
+        // refresh local sync id
+        if (!mCancelled) {
+            GTaskClient.getInstance().commitUpdate();
+            refreshLocalSyncId();
+        }
+
+    }
+
+    private void syncFolder() throws NetworkFailureException {
+        Cursor c = null;
+        String gid;
+        Node node;
+        int syncType;
+
+        if (mCancelled) {
+            return;
+        }
+
+        // for root folder
+        try {
+            c = mContentResolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,
+                    Notes.ID_ROOT_FOLDER), SqlNote.PROJECTION_NOTE, null, null, null);
+            if (c != null) {
+                c.moveToNext();
+                gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                node = mGTaskHashMap.get(gid);
+                if (node != null) {
+                    mGTaskHashMap.remove(gid);
+                    mGidToNid.put(gid, (long) Notes.ID_ROOT_FOLDER);
+                    mNidToGid.put((long) Notes.ID_ROOT_FOLDER, gid);
+                    // for system folder, only update remote name if necessary
+                    if (!node.getName().equals(
+                            GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT))
+                        doContentSync(Node.SYNC_ACTION_UPDATE_REMOTE, node, c);
+                } else {
+                    doContentSync(Node.SYNC_ACTION_ADD_REMOTE, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query root folder");
+            }
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // for call-note folder
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE, "(_id=?)",
+                    new String[] {
+                        String.valueOf(Notes.ID_CALL_RECORD_FOLDER)
+                    }, null);
+            if (c != null) {
+                if (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, (long) Notes.ID_CALL_RECORD_FOLDER);
+                        mNidToGid.put((long) Notes.ID_CALL_RECORD_FOLDER, gid);
+                        // for system folder, only update remote name if
+                        // necessary
+                        if (!node.getName().equals(
+                                GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                                        + GTaskStringUtils.FOLDER_CALL_NOTE))
+                            doContentSync(Node.SYNC_ACTION_UPDATE_REMOTE, node, c);
+                    } else {
+                        doContentSync(Node.SYNC_ACTION_ADD_REMOTE, node, c);
+                    }
+                }
+            } else {
+                Log.w(TAG, "failed to query call note folder");
+            }
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // for local existing folders
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type=? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c != null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, c.getLong(SqlNote.ID_COLUMN));
+                        mNidToGid.put(c.getLong(SqlNote.ID_COLUMN), gid);
+                        syncType = node.getSyncAction(c);
+                    } else {
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {
+                            // local add
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;
+                        } else {
+                            // remote delete
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;
+                        }
+                    }
+                    doContentSync(syncType, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query existing folder");
+            }
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // for remote add folders
+        Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();
+        while (iter.hasNext()) {
+            Map.Entry<String, TaskList> entry = iter.next();
+            gid = entry.getKey();
+            node = entry.getValue();
+            if (mGTaskHashMap.containsKey(gid)) {
+                mGTaskHashMap.remove(gid);
+                doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);
+            }
+        }
+
+        if (!mCancelled)
+            GTaskClient.getInstance().commitUpdate();
+    }
+/**
+ * 实现功能：syncType分类，addLocalNode,addRemoteNode,deleteNode,updateLocalNode,updateRemoteNode
+*/
+    private void doContentSync(int syncType, Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        MetaData meta;
+        switch (syncType) {
+            case Node.SYNC_ACTION_ADD_LOCAL:
+                addLocalNode(node);
+                break;
+            case Node.SYNC_ACTION_ADD_REMOTE:
+                addRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_DEL_LOCAL:
+                meta = mMetaHashMap.get(c.getString(SqlNote.GTASK_ID_COLUMN));
+                if (meta != null) {
+                    GTaskClient.getInstance().deleteNode(meta);
+                }
+                mLocalDeleteIdMap.add(c.getLong(SqlNote.ID_COLUMN));
+                break;
+            case Node.SYNC_ACTION_DEL_REMOTE:
+                meta = mMetaHashMap.get(node.getGid());
+                if (meta != null) {
+                    GTaskClient.getInstance().deleteNode(meta);
+                }
+                GTaskClient.getInstance().deleteNode(node);
+                break;
+            case Node.SYNC_ACTION_UPDATE_LOCAL:
+                updateLocalNode(node, c);
+                break;
+            case Node.SYNC_ACTION_UPDATE_REMOTE:
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_UPDATE_CONFLICT:
+                // merging both modifications maybe a good idea
+                // right now just use local update simply
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_NONE:
+                break;
+            case Node.SYNC_ACTION_ERROR:
+            default:
+                throw new ActionFailureException("unkown sync action type");
+        }
+    }
+/**实现功能：本地增加Node */
+    private void addLocalNode(Node node) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote;
+        if (node instanceof TaskList) {
+            if (node.getName().equals(
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT)) {
+                sqlNote = new SqlNote(mContext, Notes.ID_ROOT_FOLDER);
+            } else if (node.getName().equals(
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_CALL_NOTE)) {
+                sqlNote = new SqlNote(mContext, Notes.ID_CALL_RECORD_FOLDER);
+            } else {
+                sqlNote = new SqlNote(mContext);
+                sqlNote.setContent(node.getLocalJSONFromContent());
+                sqlNote.setParentId(Notes.ID_ROOT_FOLDER);
+            }
+        } else {
+            sqlNote = new SqlNote(mContext);
+            JSONObject js = node.getLocalJSONFromContent();
+            try {
+                if (js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+                    JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+                    if (note.has(NoteColumns.ID)) {
+                        long id = note.getLong(NoteColumns.ID);
+                        if (DataUtils.existInNoteDatabase(mContentResolver, id)) {
+                            // the id is not available, have to create a new one
+                            note.remove(NoteColumns.ID);
+                        }
+                    }
+                }
+
+                if (js.has(GTaskStringUtils.META_HEAD_DATA)) {
+                    JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                    for (int i = 0; i < dataArray.length(); i++) {
+                        JSONObject data = dataArray.getJSONObject(i);
+                        if (data.has(DataColumns.ID)) {
+                            long dataId = data.getLong(DataColumns.ID);
+                            if (DataUtils.existInDataDatabase(mContentResolver, dataId)) {
+                                // the data id is not available, have to create
+                                // a new one
+                                data.remove(DataColumns.ID);
+                            }
+                        }
+                    }
+
+                }
+            } catch (JSONException e) {
+                Log.w(TAG, e.toString());
+                e.printStackTrace();
+            }
+            sqlNote.setContent(js);
+
+            Long parentId = mGidToNid.get(((Task) node).getParent().getGid());
+            if (parentId == null) {
+                Log.e(TAG, "cannot find task's parent id locally");
+                throw new ActionFailureException("cannot add local node");
+            }
+            sqlNote.setParentId(parentId.longValue());
+        }
+
+        // create the local node
+        sqlNote.setGtaskId(node.getGid());
+        sqlNote.commit(false);
+
+        // update gid-nid mapping
+        mGidToNid.put(node.getGid(), sqlNote.getId());
+        mNidToGid.put(sqlNote.getId(), node.getGid());
+
+        // update meta
+        updateRemoteMeta(node.getGid(), sqlNote);
+    }
+/**实现功能：更新本地Node */
+    private void updateLocalNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote;
+        // update the note locally
+        sqlNote = new SqlNote(mContext, c);
+        sqlNote.setContent(node.getLocalJSONFromContent());
+
+        Long parentId = (node instanceof Task) ? mGidToNid.get(((Task) node).getParent().getGid())
+                : new Long(Notes.ID_ROOT_FOLDER);
+        if (parentId == null) {
+            Log.e(TAG, "cannot find task's parent id locally");
+            throw new ActionFailureException("cannot update local node");
+        }
+        sqlNote.setParentId(parentId.longValue());
+        sqlNote.commit(true);
+
+        // update meta info
+        updateRemoteMeta(node.getGid(), sqlNote);
+    }
+/**实现功能：远程增加node */
+    private void addRemoteNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);//从本地mContext中获取内容
+        Node n;
+
+        // update remotely
+        if (sqlNote.isNoteType()) {
+            Task task = new Task();
+            task.setContentByLocalJSON(sqlNote.getContent());
+
+            String parentGid = mNidToGid.get(sqlNote.getParentId());
+            if (parentGid == null) {
+                Log.e(TAG, "cannot find task's parent tasklist");//调试信息
+                throw new ActionFailureException("cannot add remote task");
+            }
+            mGTaskListHashMap.get(parentGid).addChildTask(task);//在本地生成的GTaskList中增加子结点
+//登录远程服务器，创建Task
+            GTaskClient.getInstance().createTask(task);
+            n = (Node) task;
+
+            // add meta
+            updateRemoteMeta(task.getGid(), sqlNote);
+        } else {
+            TaskList tasklist = null;
+
+            // we need to skip folder if it has already existed
+            String folderName = GTaskStringUtils.MIUI_FOLDER_PREFFIX;
+            if (sqlNote.getId() == Notes.ID_ROOT_FOLDER)
+                folderName += GTaskStringUtils.FOLDER_DEFAULT;
+            else if (sqlNote.getId() == Notes.ID_CALL_RECORD_FOLDER)
+                folderName += GTaskStringUtils.FOLDER_CALL_NOTE;
+            else
+                folderName += sqlNote.getSnippet();
+//iterator迭代器，通过统一的接口迭代所有的map元素
+            Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();
+            while (iter.hasNext()) {
+                Map.Entry<String, TaskList> entry = iter.next();
+                String gid = entry.getKey();
+                TaskList list = entry.getValue();
+
+                if (list.getName().equals(folderName)) {
+                    tasklist = list;
+                    if (mGTaskHashMap.containsKey(gid)) {
+                        mGTaskHashMap.remove(gid);
+                    }
+                    break;
+                }
+            }
+
+            // no match we can add now
+            if (tasklist == null) {
+                tasklist = new TaskList();
+                tasklist.setContentByLocalJSON(sqlNote.getContent());
+                GTaskClient.getInstance().createTaskList(tasklist);
+                mGTaskListHashMap.put(tasklist.getGid(), tasklist);
+            }
+            n = (Node) tasklist;
+        }
+
+        // update local note
+        sqlNote.setGtaskId(n.getGid());
+        sqlNote.commit(false);
+        sqlNote.resetLocalModified();
+        sqlNote.commit(true);
+
+        // gid-id mapping
+        //创建id间的映射
+        mGidToNid.put(n.getGid(), sqlNote.getId());
+        mNidToGid.put(sqlNote.getId(), n.getGid());
+    }
+/**实现功能：更新远端的Node，包含meta更新 */
+    private void updateRemoteNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);
+
+        // update remotely
+        node.setContentByLocalJSON(sqlNote.getContent());
+        GTaskClient.getInstance().addUpdateNode(node);//GTaskClient用途为从本地登录远端服务器
+
+        // update meta
+        updateRemoteMeta(node.getGid(), sqlNote);
+
+        // move task if necessary
+        if (sqlNote.isNoteType()) {
+            Task task = (Task) node;
+            TaskList preParentList = task.getParent();
+//preParentList为通过node获取的父节点列表
+            String curParentGid = mNidToGid.get(sqlNote.getParentId());
+            //curParentGid为通过光标在数据库中找到sqlNote的mParentId，再通过mNidToGid有long类型转为String类型的Gid
+            if (curParentGid == null) {
+                Log.e(TAG, "cannot find task's parent tasklist");
+                throw new ActionFailureException("cannot update remote task");
+            }
+            TaskList curParentList = mGTaskListHashMap.get(curParentGid);
+//通过HashMap找到对应的Gid的TaskList
+            if (preParentList != curParentList) {
+                preParentList.removeChildTask(task);
+                curParentList.addChildTask(task);
+                GTaskClient.getInstance().moveTask(task, preParentList, curParentList);
+            }
+        }
+
+        // clear local modified flag
+        sqlNote.resetLocalModified();
+        //commit到本地数据库
+        sqlNote.commit(true);
+    }
+/**实现功能：升级远程meta，meta---元数据---计算机文件系统管理数据---管理数据的数据 */
+    private void updateRemoteMeta(String gid, SqlNote sqlNote) throws NetworkFailureException {
+        if (sqlNote != null && sqlNote.isNoteType()) {
+            MetaData metaData = mMetaHashMap.get(gid);
+            if (metaData != null) {
+                metaData.setMeta(gid, sqlNote.getContent());
+                GTaskClient.getInstance().addUpdateNode(metaData);
+            } else {
+                metaData = new MetaData();
+                metaData.setMeta(gid, sqlNote.getContent());
+                mMetaList.addChildTask(metaData);
+                mMetaHashMap.put(gid, metaData);
+                GTaskClient.getInstance().createTask(metaData);
+            }
+        }
+    }
+/**实现功能：刷新本地，给sync的ID对应上最后更改过的对象 */
+    private void refreshLocalSyncId() throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        // get the latest gtask list
+        //获取最近的gtask list
+        mGTaskHashMap.clear();
+        mGTaskListHashMap.clear();
+        mMetaHashMap.clear();
+        initGTaskList();
+
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type<>? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");//query语句：五个参数，NoteColumns.TYPE + "DESC"-----为按类型递减顺序返回查询结果，new String[]{String.valueof(Notes.TYPE_SYSTEM),
+                    //String.valueof(Notes.ID_TRASH_FOLER)}-----为选择参数，"(type<>?AND parent_id<>?)"------指明返回行过滤器，SqlNote.PROJECTION_NOTE-----对应返回的数据列的名字，
+                    //Notes.CONTENT_NOTE_URI------contentProvider包含所有数据集所对应的uri
+            if (c != null) {
+                while (c.moveToNext()) {
+                    String gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    Node node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        ContentValues values = new ContentValues();//在ContentValues中创建键值对，准备通过contentResolver写入数据
+                        values.put(NoteColumns.SYNC_ID, node.getLastModified());
+                        mContentResolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,//进行批量更改，选择参数为NULL，应该可以用insert替换，参数分别为表名和需要更新的value对象
+                                c.getLong(SqlNote.ID_COLUMN)), values, null, null);
+                    } else {
+                        Log.e(TAG, "something is missed");
+                        throw new ActionFailureException(
+                                "some local items don't have gid after sync");
+                    }
+                }
+            } else {
+                Log.w(TAG, "failed to query local note to refresh sync id");
+            }
+        } finally {
+            if (c != null) {
+                c.close();
+                c = null;
+            }
+        }
+    }
+/**实现功能：获取同步账号，mAccount.name */
+    public String getSyncAccount() {
+        return GTaskClient.getInstance().getSyncAccount().name;
+    }
+/**实现功能：取消同步，置mCancelled 为 true */
+    public void cancelSync() {
+        mCancelled = true;
+    }
+}

GTaskStringUtils.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+//简介：定义了很多的静态字符串，目的就是为了提供jsonObject中相应字符串的“key”。把这些静态的定义单独写到了一个类里面，这是非常好的编程规范
+package net.micode.notes.tool;
+//这个类就是定义了一堆static String，实际就是为jsonObject提供key，把这些定义全部写到一个类里，方便查看管理，是一个非常好的编程习惯
+public class GTaskStringUtils {
+
+    public final static String GTASK_JSON_ACTION_ID = "action_id";
+
+    public final static String GTASK_JSON_ACTION_LIST = "action_list";
+
+    public final static String GTASK_JSON_ACTION_TYPE = "action_type";
+
+    public final static String GTASK_JSON_ACTION_TYPE_CREATE = "create";
+
+    public final static String GTASK_JSON_ACTION_TYPE_GETALL = "get_all";
+
+    public final static String GTASK_JSON_ACTION_TYPE_MOVE = "move";
+
+    public final static String GTASK_JSON_ACTION_TYPE_UPDATE = "update";
+
+    public final static String GTASK_JSON_CREATOR_ID = "creator_id";
+
+    public final static String GTASK_JSON_CHILD_ENTITY = "child_entity";
+
+    public final static String GTASK_JSON_CLIENT_VERSION = "client_version";
+
+    public final static String GTASK_JSON_COMPLETED = "completed";
+
+    public final static String GTASK_JSON_CURRENT_LIST_ID = "current_list_id";
+
+    public final static String GTASK_JSON_DEFAULT_LIST_ID = "default_list_id";
+
+    public final static String GTASK_JSON_DELETED = "deleted";
+
+    public final static String GTASK_JSON_DEST_LIST = "dest_list";
+
+    public final static String GTASK_JSON_DEST_PARENT = "dest_parent";
+
+    public final static String GTASK_JSON_DEST_PARENT_TYPE = "dest_parent_type";
+
+    public final static String GTASK_JSON_ENTITY_DELTA = "entity_delta";
+
+    public final static String GTASK_JSON_ENTITY_TYPE = "entity_type";
+
+    public final static String GTASK_JSON_GET_DELETED = "get_deleted";
+
+    public final static String GTASK_JSON_ID = "id";
+
+    public final static String GTASK_JSON_INDEX = "index";
+
+    public final static String GTASK_JSON_LAST_MODIFIED = "last_modified";
+
+    public final static String GTASK_JSON_LATEST_SYNC_POINT = "latest_sync_point";
+
+    public final static String GTASK_JSON_LIST_ID = "list_id";
+
+    public final static String GTASK_JSON_LISTS = "lists";
+
+    public final static String GTASK_JSON_NAME = "name";
+
+    public final static String GTASK_JSON_NEW_ID = "new_id";
+
+    public final static String GTASK_JSON_NOTES = "notes";
+
+    public final static String GTASK_JSON_PARENT_ID = "parent_id";
+
+    public final static String GTASK_JSON_PRIOR_SIBLING_ID = "prior_sibling_id";
+
+    public final static String GTASK_JSON_RESULTS = "results";
+
+    public final static String GTASK_JSON_SOURCE_LIST = "source_list";
+
+    public final static String GTASK_JSON_TASKS = "tasks";
+
+    public final static String GTASK_JSON_TYPE = "type";
+
+    public final static String GTASK_JSON_TYPE_GROUP = "GROUP";
+
+    public final static String GTASK_JSON_TYPE_TASK = "TASK";
+
+    public final static String GTASK_JSON_USER = "user";
+
+    public final static String MIUI_FOLDER_PREFFIX = "[MIUI_Notes]";
+
+    public final static String FOLDER_DEFAULT = "Default";
+
+    public final static String FOLDER_CALL_NOTE = "Call_Note";
+
+    public final static String FOLDER_META = "METADATA";
+
+    public final static String META_HEAD_GTASK_ID = "meta_gid";
+
+    public final static String META_HEAD_NOTE = "meta_note";
+
+    public final static String META_HEAD_DATA = "meta_data";
+
+    public final static String META_NOTE_NAME = "[META INFO] DON'T UPDATE AND DELETE";
+
+}

GTaskSyncService.java

@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.app.Activity;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.IBinder;
+/*
+ * Service是在一段不定的时间运行在后台，不和用户交互的应用组件
+ * 主要方法：
+ * private void startSync()  启动一个同步工作
+ * private void cancelSync() 取消同步
+ * public void onCreate()
+ * public int onStartCommand(Intent intent, int flags, int startId)  service生命周期的组成部分，相当于重启service（比如在被暂停之后），而不是创建一个新的service
+ * public void onLowMemory()  在没有内存的情况下如果存在service则结束掉这的service
+ * public IBinder onBind()
+ * public void sendBroadcast(String msg)   发送同步的相关通知
+ * public static void startSync(Activity activity)
+ * public static void cancelSync(Context context) 
+ * public static boolean isSyncing()  判读是否在进行同步
+ * public static String getProgressString()  获取当前进度的信息
+ */
+public class GTaskSyncService extends Service {
+    public final static String ACTION_STRING_NAME = "sync_action_type";
+
+    public final static int ACTION_START_SYNC = 0;
+
+    public final static int ACTION_CANCEL_SYNC = 1;
+
+    public final static int ACTION_INVALID = 2;
+
+    public final static String GTASK_SERVICE_BROADCAST_NAME = "net.micode.notes.gtask.remote.gtask_sync_service";
+
+    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";
+
+    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";
+
+    private static GTaskASyncTask mSyncTask = null;
+
+    private static String mSyncProgress = "";
+ //开始一个同步的工作
+    private void startSync() {
+        if (mSyncTask == null) {
+            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
+                public void onComplete() {
+                    mSyncTask = null;
+                    sendBroadcast("");
+                    stopSelf();
+                }
+            });
+            sendBroadcast("");
+            mSyncTask.execute();//这个函数让任务是以单线程队列方式或线程池队列方式运行
+        }
+    }
+
+    private void cancelSync() {
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+
+    @Override
+    public void onCreate() {//初始化一个service
+        mSyncTask = null;
+    }
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        Bundle bundle = intent.getExtras();
+        if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) {
+            switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) {
+                //两种情况，开始同步或者取消同步
+                case ACTION_START_SYNC:
+                    startSync();
+                    break;
+                case ACTION_CANCEL_SYNC:
+                    cancelSync();
+                    break;
+                default:
+                    break;
+            }
+            return START_STICKY;//等待新的intent来是这个service继续运行
+        }
+        return super.onStartCommand(intent, flags, startId);
+    }
+
+    @Override
+    public void onLowMemory() {
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+
+    public IBinder onBind(Intent intent) {
+        return null;
+    }
+
+    public void sendBroadcast(String msg) {
+        mSyncProgress = msg;
+        Intent intent = new Intent(GTASK_SERVICE_BROADCAST_NAME);//创建一个新的Intent
+        intent.putExtra(GTASK_SERVICE_BROADCAST_IS_SYNCING, mSyncTask != null);//附加INTENT中的相应参数的值
+        intent.putExtra(GTASK_SERVICE_BROADCAST_PROGRESS_MSG, msg);
+        sendBroadcast(intent); //发送这个通知
+    }
+
+    public static void startSync(Activity activity) {//执行一个service，service的内容里的同步动作就是开始同步
+        GTaskManager.getInstance().setActivityContext(activity);
+        Intent intent = new Intent(activity, GTaskSyncService.class);
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_START_SYNC);
+        activity.startService(intent);
+    }
+
+    public static void cancelSync(Context context) {//执行一个service，service的内容里的同步动作就是取消同步
+        Intent intent = new Intent(context, GTaskSyncService.class);
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_CANCEL_SYNC);
+        context.startService(intent);
+    }
+
+    public static boolean isSyncing() {
+        return mSyncTask != null;
+    }
+
+    public static String getProgressString() {
+        return mSyncProgress;
+    }
+}

MetaData.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+public class MetaData extends Task {
+    /**实现功能：得到类的简写名称存入字符串TAG中（调用getSimpleName()函数） */
+    private final static String TAG = MetaData.class.getSimpleName();
+
+    private String mRelatedGid = null;
+    /**实现功能：设置数据，即生成元数据库（调用JSONObject库函数put（），Task类中的setNotes（）和setName（）函数） */
+    public void setMeta(String gid, JSONObject metaInfo) {
+        //对函数块进行注释
+        try {
+            metaInfo.put(GTaskStringUtils.META_HEAD_GTASK_ID, gid);
+            /**将这对键值放入metaInfo这个jsonobject对象中 */
+        } catch (JSONException e) {
+            Log.e(TAG, "failed to put related gid");
+            /**输出错误信息 */
+        }
+        setNotes(metaInfo.toString());
+        setName(GTaskStringUtils.META_NOTE_NAME);
+    }
+    /**实现功能：获取相关联的Gid */
+    public String getRelatedGid() {
+        return mRelatedGid;
+    }
+/**实现功能：判断当前数据是否为空，若为空则返回真即值得保存 */
+    @Override
+    public boolean isWorthSaving() {
+        return getNotes() != null;
+    }
+/**实现功能：使用远程json数据对象设置元数据内容（调用父类Task中的setContentByRemoteJSON（）函数） */
+    @Override
+    public void setContentByRemoteJSON(JSONObject js) {
+        super.setContentByRemoteJSON(js);
+        if (getNotes() != null) {
+            try {
+                JSONObject metaInfo = new JSONObject(getNotes().trim());
+                mRelatedGid = metaInfo.getString(GTaskStringUtils.META_HEAD_GTASK_ID);
+            } catch (JSONException e) {
+                Log.w(TAG, "failed to get related gid");
+                /**输出警告信息 */
+                mRelatedGid = null;
+            }
+        }
+    }
+/**实现功能：使用本地json数据对象设置元数据内容，一般不会用到，若用到，则抛出异常 */
+    @Override
+    public void setContentByLocalJSON(JSONObject js) {
+        // this function should not be called
+        throw new IllegalAccessError("MetaData:setContentByLocalJSON should not be called");
+        /**传递非法参数异常 */
+    }
+/**实现功能：从元数据内容中获取本地json对象，一般不会用到，若用到，则抛出异常 */
+    @Override
+    public JSONObject getLocalJSONFromContent() {
+        throw new IllegalAccessError("MetaData:getLocalJSONFromContent should not be called");
+        /**传递非法参数异常 */
+    }
+/**实现功能：获取同步动作状态，一般不会用到，若用到，则抛出异常 */
+    @Override
+    public int getSyncAction(Cursor c) {
+        throw new IllegalAccessError("MetaData:getSyncAction should not be called");
+        /**传递非法参数异常 */
+    }
+
+}

NetworkFailureException.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.exception;
+
+public class NetworkFailureException extends Exception {
+    private static final long serialVersionUID = 2107610287180234136L;
+
+    public NetworkFailureException() {
+        super();
+    }
+
+    public NetworkFailureException(String paramString) {
+        super(paramString);
+    }
+
+    public NetworkFailureException(String paramString, Throwable paramThrowable) {
+        super(paramString, paramThrowable);
+    }
+}

Node.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+
+import org.json.JSONObject;
+/**同步操作的基础数据类型，定义了相关指示同步操作的常量 */
+public abstract class Node {
+    //定义了各种用于表征同步状态的常量
+    public static final int SYNC_ACTION_NONE = 0;//本地和云端都无可更新内容（即本地和云端内容一致）
+
+    public static final int SYNC_ACTION_ADD_REMOTE = 1;//需要在远程云端增加内容
+
+    public static final int SYNC_ACTION_ADD_LOCAL = 2;//需要在本地增加内容
+
+    public static final int SYNC_ACTION_DEL_REMOTE = 3;//需要在远程云端删除云端
+
+    public static final int SYNC_ACTION_DEL_LOCAL = 4;//需要在本地删除内容
+
+    public static final int SYNC_ACTION_UPDATE_REMOTE = 5;//需要将本地内容更新到远程云端
+
+    public static final int SYNC_ACTION_UPDATE_LOCAL = 6;//需要将远程云端内容更新到本地
+
+    public static final int SYNC_ACTION_UPDATE_CONFLICT = 7;//同步出现冲突
+
+    public static final int SYNC_ACTION_ERROR = 8;//同步出现错误
+
+    private String mGid;
+
+    private String mName;
+
+    private long mLastModified;//记录最后一次修改时间
+
+    private boolean mDeleted;//表征是否被删除
+
+    public Node() {
+        mGid = null;
+        mName = "";
+        mLastModified = 0;
+        mDeleted = false;
+    }
+
+    public abstract JSONObject getCreateAction(int actionId);
+
+    public abstract JSONObject getUpdateAction(int actionId);
+
+    public abstract void setContentByRemoteJSON(JSONObject js);
+
+    public abstract void setContentByLocalJSON(JSONObject js);
+
+    public abstract JSONObject getLocalJSONFromContent();
+
+    public abstract int getSyncAction(Cursor c);
+
+    public void setGid(String gid) {
+        this.mGid = gid;
+    }
+
+    public void setName(String name) {
+        this.mName = name;
+    }
+
+    public void setLastModified(long lastModified) {
+        this.mLastModified = lastModified;
+    }
+
+    public void setDeleted(boolean deleted) {
+        this.mDeleted = deleted;
+    }
+
+    public String getGid() {
+        return this.mGid;
+    }
+
+    public String getName() {
+        return this.mName;
+    }
+
+    public long getLastModified() {
+        return this.mLastModified;
+    }
+
+    public boolean getDeleted() {
+        return this.mDeleted;
+    }
+
+}

Note.java

@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.model;
+import android.content.ContentProviderOperation;//批量的更新、插入、删除数据
+import android.content.ContentProviderResult;//操作后的结果
+import android.content.ContentUris;//用于添加和获取uri后面的id
+import android.content.ContentValues;//一种用于存储基本数据类型数据的存储机制
+import android.content.Context;//需要用该类来弄清楚调用者的实例
+import android.content.OperationApplicationException;//操作应用程序容错
+import android.net.Uri;//表示待操作的数据
+import android.os.RemoteException;//远程容错
+import android.util.Log;//输出日志，比如说出错、警告等
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.Notes.TextNote;
+
+import java.util.ArrayList;
+
+
+public class Note {
+    private ContentValues mNoteDiffValues;
+    private NoteData mNoteData;
+    private static final String TAG = "Note";
+    /**
+     * Create a new note id for adding a new note to databases
+     */
+    public static synchronized long getNewNoteId(Context context, long folderId) {
+        // Create a new note in the database
+        ContentValues values = new ContentValues();
+        long createdTime = System.currentTimeMillis();
+        values.put(NoteColumns.CREATED_DATE, createdTime);
+        values.put(NoteColumns.MODIFIED_DATE, createdTime);
+        values.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+        values.put(NoteColumns.PARENT_ID, folderId);//将数据写入数据库表格
+        Uri uri = context.getContentResolver().insert(Notes.CONTENT_NOTE_URI, values);
+//ContentResolver()主要是实现外部应用对ContentProvider中的数据
+//进行添加、删除、修改和查询操作
+        long noteId = 0;
+        try {
+            noteId = Long.valueOf(uri.getPathSegments().get(1));
+        } catch (NumberFormatException e) {
+            Log.e(TAG, "Get note id error :" + e.toString());
+            noteId = 0;
+        }//try-catch异常处理
+        if (noteId == -1) {
+            throw new IllegalStateException("Wrong note id:" + noteId);
+        }
+        return noteId;
+    }
+
+    public Note() {
+        mNoteDiffValues = new ContentValues();
+        mNoteData = new NoteData();
+    }//定义两个变量用来存储便签的数据，一个是存储便签属性，一个是存储便签内容
+
+    public void setNoteValue(String key, String value) {
+        mNoteDiffValues.put(key, value);
+        mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1);
+        mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis());
+    }//设置数据库表格的标签属性数据
+
+    public void setTextData(String key, String value) {
+        mNoteData.setTextData(key, value);
+    }//设置数据库表格的标签文本内容的数据
+
+    public void setTextDataId(long id) {
+       mNoteData.setTextDataId(id);
+    }//设置文本数据的id
+    public long getTextDataId() {
+        return mNoteData.mTextDataId;
+    }//得到文本数据的id
+
+    public void setCallDataId(long id) {
+        mNoteData.setCallDataId(id);
+    }//设置电话号码数据的id
+
+    public void setCallData(String key, String value) {
+        mNoteData.setCallData(key, value);
+    }//得到电话号码数据的id
+
+    public boolean isLocalModified() {
+        return mNoteDiffValues.size() > 0 || mNoteData.isLocalModified();
+    }//判断是否是本地修改
+
+    public boolean syncNote(Context context, long noteId) {
+        if (noteId <= 0) {
+            throw new IllegalArgumentException("Wrong note id:" + noteId);
+        }
+
+        if (!isLocalModified()) {
+            return true;
+        }
+
+        /**
+         * In theory, once data changed, the note should be updated on {@link NoteColumns#LOCAL_MODIFIED} and
+         * {@link NoteColumns#MODIFIED_DATE}. For data safety, though update note fails, we also update the
+         * note data info
+         */
+        if (context.getContentResolver().update(
+                ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), mNoteDiffValues, null,
+                null) == 0) {
+            Log.e(TAG, "Update note error, should not happen");
+            // Do not return, fall through
+        }
+        mNoteDiffValues.clear();
+
+        if (mNoteData.isLocalModified()
+                && (mNoteData.pushIntoContentResolver(context, noteId) == null)) {
+            return false;
+        }
+
+        return true;
+    }//判断数据是否同步
+
+    private class NoteData {//定义一个基本的便签内容的数据类，主要包含文本数据和电话号码数据
+        private long mTextDataId;
+
+        private ContentValues mTextDataValues;//文本数据
+
+        private long mCallDataId;
+
+        private ContentValues mCallDataValues;//电话号码数据
+
+        private static final String TAG = "NoteData";
+
+        public NoteData() {
+            mTextDataValues = new ContentValues();
+            mCallDataValues = new ContentValues();
+            mTextDataId = 0;
+            mCallDataId = 0;
+        }
+//下面是上述几个函数的具体实现
+        boolean isLocalModified() {
+            return mTextDataValues.size() > 0 || mCallDataValues.size() > 0;
+        }
+
+        void setTextDataId(long id) {
+            if(id <= 0) {
+                throw new IllegalArgumentException("Text data id should larger than 0");
+            }
+            mTextDataId = id;
+        }
+
+        void setCallDataId(long id) {
+            if (id <= 0) {
+                throw new IllegalArgumentException("Call data id should larger than 0");
+            }
+            mCallDataId = id;
+        }
+
+        void setCallData(String key, String value) {
+            mCallDataValues.put(key, value);
+            mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1);
+            mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis());
+        }
+
+        void setTextData(String key, String value) {
+            mTextDataValues.put(key, value);
+            mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1);
+            mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis());
+        }
+//下面函数的作用是将新的数据通过uri的操作存储到数据库
+        Uri pushIntoContentResolver(Context context, long noteId) {
+            /**
+             * Check for safety
+             */
+            if (noteId <= 0) {
+                throw new IllegalArgumentException("Wrong note id:" + noteId);
+            }//判断数据是否合法
+
+            ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+            ContentProviderOperation.Builder builder = null;//数据库的操作列表
+
+            if(mTextDataValues.size() > 0) {
+                mTextDataValues.put(DataColumns.NOTE_ID, noteId);
+                if (mTextDataId == 0) {
+                    mTextDataValues.put(DataColumns.MIME_TYPE, TextNote.CONTENT_ITEM_TYPE);
+                    Uri uri = context.getContentResolver().insert(Notes.CONTENT_DATA_URI,
+                            mTextDataValues);
+                    try {
+                        setTextDataId(Long.valueOf(uri.getPathSegments().get(1)));
+                    } catch (NumberFormatException e) {
+                        Log.e(TAG, "Insert new text data fail with noteId" + noteId);
+                        mTextDataValues.clear();
+                        return null;
+                    }
+                } else {
+                    builder = ContentProviderOperation.newUpdate(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mTextDataId));
+                    builder.withValues(mTextDataValues);
+                    operationList.add(builder.build());
+                }
+                mTextDataValues.clear();
+            }//把文本数据存入DataColumns
+
+            if(mCallDataValues.size() > 0) {
+                mCallDataValues.put(DataColumns.NOTE_ID, noteId);
+                if (mCallDataId == 0) {
+                    mCallDataValues.put(DataColumns.MIME_TYPE, CallNote.CONTENT_ITEM_TYPE);
+                    Uri uri = context.getContentResolver().insert(Notes.CONTENT_DATA_URI,
+                            mCallDataValues);
+                    try {
+                        setCallDataId(Long.valueOf(uri.getPathSegments().get(1)));
+                    } catch (NumberFormatException e) {
+                        Log.e(TAG, "Insert new call data fail with noteId" + noteId);
+                        mCallDataValues.clear();
+                        return null;
+                    }
+                } else {
+                    builder = ContentProviderOperation.newUpdate(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mCallDataId));
+                    builder.withValues(mCallDataValues);
+                    operationList.add(builder.build());
+                }
+                mCallDataValues.clear();
+            }//吧电话号码数据存入DataColumns
+
+            if (operationList.size() > 0) {
+                try {
+                    ContentProviderResult[] results = context.getContentResolver().applyBatch(
+                            Notes.AUTHORITY, operationList);
+                    return (results == null || results.length == 0 || results[0] == null) ? null
+                            : ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                } catch (RemoteException e) {
+                    Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+                    return null;
+                } catch (OperationApplicationException e) {
+                    Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+                    return null;
+                }
+            }//存储过程中的异常处理
+            return null;
+        }
+    }
+}

NoteEditText.java

@@ -0,0 +1,264 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.text.Layout;
+import android.text.Selection;
+import android.text.Spanned;
+import android.text.TextUtils;
+import android.text.style.URLSpan;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.ContextMenu;
+import android.view.KeyEvent;
+import android.view.MenuItem;
+import android.view.MenuItem.OnMenuItemClickListener;
+import android.view.MotionEvent;
+import android.widget.EditText;
+
+import net.micode.notes.R;
+
+import java.util.HashMap;
+import java.util.Map;
+//继承EditText，设置便签设置文本框
+public class NoteEditText extends EditText {
+    private static final String TAG = "NoteEditText";
+    private int mIndex;
+    private int mSelectionStartBeforeDelete;
+
+    private static final String SCHEME_TEL = "tel:" ;
+    private static final String SCHEME_HTTP = "http:" ;
+    private static final String SCHEME_EMAIL = "mailto:" ;
+//建立一个字符和整数的hash表，用于链接电话、网站和邮箱
+    private static final Map<String, Integer> sSchemaActionResMap = new HashMap<String, Integer>();
+    static {
+        sSchemaActionResMap.put(SCHEME_TEL, R.string.note_link_tel);
+        sSchemaActionResMap.put(SCHEME_HTTP, R.string.note_link_web);
+        sSchemaActionResMap.put(SCHEME_EMAIL, R.string.note_link_email);
+    }
+
+    /**
+     * Call by the {@link NoteEditActivity} to delete or add edit text
+     */
+    //在NoteEditActivity中删除或添加文本的操作，可以看作是一个文本是否被变的标记
+    public interface OnTextViewChangeListener {
+        /**
+         * Delete current edit text when {@link KeyEvent#KEYCODE_DEL} happens
+         * and the text is null
+         */
+        //处理删除案件时的操作
+        void onEditTextDelete(int index, String text);
+
+        /**
+         * Add edit text after current edit text when {@link KeyEvent#KEYCODE_ENTER}
+         * happen
+         */
+        //处理进入软件时的操作
+        void onEditTextEnter(int index, String text);
+
+        /**
+         * Hide or show item option when text change
+         */
+        void onTextChange(int index, boolean hasText);
+    }
+
+    private OnTextViewChangeListener mOnTextViewChangeListener;
+//根据context设置文本
+    public NoteEditText(Context context) {
+        super(context, null);//用super引用父类变量
+        mIndex = 0;
+    }
+//设置当前光标
+    public void setIndex(int index) {
+        mIndex = index;
+    }
+//初始化文本修改标记
+    public void setOnTextViewChangeListener(OnTextViewChangeListener listener) {
+        mOnTextViewChangeListener = listener;
+    }
+//AttributeSet自定义空控件属性，用于维护便签动态变化的属性
+//初始化便签
+    public NoteEditText(Context context, AttributeSet attrs) {
+        super(context, attrs, android.R.attr.editTextStyle);
+    }
+//根据defStyle自动初始化
+    public NoteEditText(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        // TODO Auto-generated constructor stub
+    }
+
+    @Override
+    //view里的函数，处理手机屏幕的所有事件 
+    /**参数event为手机屏幕触摸事件封装类的对象，其中封装了该事件的所有信息，
+     * 例如触摸的位置、触摸的类型以及触摸的时间等。该对象会在用户触摸手机屏幕时被创建
+     */
+    public boolean onTouchEvent(MotionEvent event) {
+        switch (event.getAction()) {
+            //重写了需要处理屏幕被按下的事件
+            case MotionEvent.ACTION_DOWN:
+//更新当前坐标值
+                int x = (int) event.getX();
+                int y = (int) event.getY();
+                x -= getTotalPaddingLeft();
+                y -= getTotalPaddingTop();
+                x += getScrollX();
+                y += getScrollY();
+//用布局控件layout根据x、y的新值设置新的位置
+                Layout layout = getLayout();
+                int line = layout.getLineForVertical(y);
+                int off = layout.getOffsetForHorizontal(line, x);
+                //更新光标新的位置
+                Selection.setSelection(getText(), off);
+                break;
+        }
+
+        return super.onTouchEvent(event);
+    }
+
+    @Override
+    /**函数功能：处理用户按下一个键盘按键时会触发的事件 */
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        switch (keyCode) {
+            //根据按键的unicode编码值来处理
+            case KeyEvent.KEYCODE_ENTER:
+                //“进入”按键
+                if (mOnTextViewChangeListener != null) {
+                    return false;
+                }
+                break;
+            case KeyEvent.KEYCODE_DEL:
+                //删除按键
+                mSelectionStartBeforeDelete = getSelectionStart();
+                break;
+            default:
+                break;
+        }
+        //继续执行父类的其他点击事件
+        return super.onKeyDown(keyCode, event);
+    }
+
+    @Override
+    /**函数功能：处理用户松开一个键盘按键时会触发的事件 */
+    public boolean onKeyUp(int keyCode, KeyEvent event) {
+        switch(keyCode) {
+            //根据按键的unicode编码值来处理，有删除和进入两种操作
+            case KeyEvent.KEYCODE_DEL:
+                if (mOnTextViewChangeListener != null) {
+                    //若是被修改过
+                    if (0 == mSelectionStartBeforeDelete && mIndex != 0) {
+                        //若是之前有被修改并且文档不为空
+                        mOnTextViewChangeListener.onEditTextDelete(mIndex, getText().toString());
+                        //利用上文OnTextViewChangeListener对KEYCODE_DEL按键情况的删除函数进行删除
+                        return true;
+                    }
+                } else {
+                    Log.d(TAG, "OnTextViewChangeListener was not seted");
+                    //其他情况报错，文档的改动监听器并没有建立
+                }
+                break;
+            case KeyEvent.KEYCODE_ENTER:
+                //同上也是分为监听器是否建立两种情况
+                if (mOnTextViewChangeListener != null) {
+                    int selectionStart = getSelectionStart();
+                    //获取当前位置
+                    String text = getText().subSequence(selectionStart, length()).toString();
+                    //获取当前文本
+                    setText(getText().subSequence(0, selectionStart));
+                    //根据获取的文本设置当前文本
+                    mOnTextViewChangeListener.onEditTextEnter(mIndex + 1, text);
+                    //条件满足情况下，添加新文本
+                } else {
+                    Log.d(TAG, "OnTextViewChangeListener was not seted");
+                    //其他情况报错，文档的改动监听器并没有建立
+                }
+                break;
+            default:
+                break;
+        }
+        //继续执行父类的其他按键弹起的事件
+        return super.onKeyUp(keyCode, event);
+    }
+
+    @Override
+    /**
+     * 函数功能：当焦点发生变化时，会自动调用该方法来处理焦点改变的事件
+     * 参数：focused表示触发该事件的view是否获得了焦点，当该控件获得焦点时，focused等于true，否则等于false
+     * direction表示焦点移动的方向，用数值表示
+     * rect表示在触发事件的view的坐标系中，前一个获得焦点的矩形区域，即表示焦点是从哪里来的。如果不可用则为null
+     */
+    protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
+        if (mOnTextViewChangeListener != null) {
+            //若监听器已经建立
+            if (!focused && TextUtils.isEmpty(getText())) {
+                //获得到焦点并且不为空
+                mOnTextViewChangeListener.onTextChange(mIndex, false);
+                //mOnTextViewChangeListener子函数，置true显示事件选项
+            } else {
+                mOnTextViewChangeListener.onTextChange(mIndex, true);
+            }
+        }
+        //继续执行父类的其他焦点变化的事件
+        super.onFocusChanged(focused, direction, previouslyFocusedRect);
+    }
+
+    @Override
+    /**函数功能：生成上下文菜单 */
+    protected void onCreateContextMenu(ContextMenu menu) {
+        if (getText() instanceof Spanned) {
+            //有文本存在
+            int selStart = getSelectionStart();
+            int selEnd = getSelectionEnd();
+//获取文本开始和结尾位置
+            int min = Math.min(selStart, selEnd);
+            int max = Math.max(selStart, selEnd);
+//获取开始到结尾的最大值和最小值
+            final URLSpan[] urls = ((Spanned) getText()).getSpans(min, max, URLSpan.class);
+           //设置url的信息的范围值
+            if (urls.length == 1) {
+                int defaultResId = 0;
+                for(String schema: sSchemaActionResMap.keySet()) {
+                    //获取计划表中所有的key值
+                    if(urls[0].getURL().indexOf(schema) >= 0) {
+                        //若url可以添加则在添加后将defaultResId置为key所映射的值
+                        defaultResId = sSchemaActionResMap.get(schema);
+                        break;
+                    }
+                }
+
+                if (defaultResId == 0) {
+                    //defaultResId == 0则说明url并没有添加任何东西，所以置为连接其他SchemaActionResMap的值
+                    defaultResId = R.string.note_link_other;
+                }
+//建立菜单
+                menu.add(0, 0, 0, defaultResId).setOnMenuItemClickListener(
+                        new OnMenuItemClickListener() {
+                            //新建按键监听器
+                            public boolean onMenuItemClick(MenuItem item) {
+                                // goto a new intent
+                                urls[0].onClick(NoteEditText.this);
+                                //根据相应的文本设置菜单的按键
+                                return true;
+                            }
+                        });
+            }
+        }
+        //继续执行父类的其他菜单创建的事件
+        super.onCreateContextMenu(menu);
+    }
+}

NoteItemData.java

@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.text.TextUtils;
+
+import net.micode.notes.data.Contact;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.tool.DataUtils;
+
+
+public class NoteItemData {
+    static final String [] PROJECTION = new String [] {
+        NoteColumns.ID,
+        NoteColumns.ALERTED_DATE,
+        NoteColumns.BG_COLOR_ID,
+        NoteColumns.CREATED_DATE,
+        NoteColumns.HAS_ATTACHMENT,
+        NoteColumns.MODIFIED_DATE,
+        NoteColumns.NOTES_COUNT,
+        NoteColumns.PARENT_ID,
+        NoteColumns.SNIPPET,
+        NoteColumns.TYPE,
+        NoteColumns.WIDGET_ID,
+        NoteColumns.WIDGET_TYPE,
+    };
+//常量标记和数据就不一一标记了，意义翻译基本就知道
+    private static final int ID_COLUMN                    = 0;
+    private static final int ALERTED_DATE_COLUMN          = 1;
+    private static final int BG_COLOR_ID_COLUMN           = 2;
+    private static final int CREATED_DATE_COLUMN          = 3;
+    private static final int HAS_ATTACHMENT_COLUMN        = 4;
+    private static final int MODIFIED_DATE_COLUMN         = 5;
+    private static final int NOTES_COUNT_COLUMN           = 6;
+    private static final int PARENT_ID_COLUMN             = 7;
+    private static final int SNIPPET_COLUMN               = 8;
+    private static final int TYPE_COLUMN                  = 9;
+    private static final int WIDGET_ID_COLUMN             = 10;
+    private static final int WIDGET_TYPE_COLUMN           = 11;
+
+    private long mId;
+    private long mAlertDate;
+    private int mBgColorId;
+    private long mCreatedDate;
+    private boolean mHasAttachment;
+    private long mModifiedDate;
+    private int mNotesCount;
+    private long mParentId;
+    private String mSnippet;
+    private int mType;
+    private int mWidgetId;
+    private int mWidgetType;
+    private String mName;
+    private String mPhoneNumber;
+
+    private boolean mIsLastItem;
+    private boolean mIsFirstItem;
+    private boolean mIsOnlyOneItem;
+    private boolean mIsOneNoteFollowingFolder;
+    private boolean mIsMultiNotesFollowingFolder;
+//初始化NoteItemData，主要利用光标cursor获取的东西
+    public NoteItemData(Context context, Cursor cursor) {
+        //getxxx为转换格式
+        mId = cursor.getLong(ID_COLUMN);
+        mAlertDate = cursor.getLong(ALERTED_DATE_COLUMN);
+        mBgColorId = cursor.getInt(BG_COLOR_ID_COLUMN);
+        mCreatedDate = cursor.getLong(CREATED_DATE_COLUMN);
+        mHasAttachment = (cursor.getInt(HAS_ATTACHMENT_COLUMN) > 0) ? true : false;
+        mModifiedDate = cursor.getLong(MODIFIED_DATE_COLUMN);
+        mNotesCount = cursor.getInt(NOTES_COUNT_COLUMN);
+        mParentId = cursor.getLong(PARENT_ID_COLUMN);
+        mSnippet = cursor.getString(SNIPPET_COLUMN);
+        mSnippet = mSnippet.replace(NoteEditActivity.TAG_CHECKED, "").replace(
+                NoteEditActivity.TAG_UNCHECKED, "");
+        mType = cursor.getInt(TYPE_COLUMN);
+        mWidgetId = cursor.getInt(WIDGET_ID_COLUMN);
+        mWidgetType = cursor.getInt(WIDGET_TYPE_COLUMN);
+//初始化电话号码的信息
+        mPhoneNumber = "";
+        if (mParentId == Notes.ID_CALL_RECORD_FOLDER) {
+            mPhoneNumber = DataUtils.getCallNumberByNoteId(context.getContentResolver(), mId);
+            if (!TextUtils.isEmpty(mPhoneNumber)) {//mPhoneNumber里有符合字符串，则用contact功能连接
+                mName = Contact.getContact(context, mPhoneNumber);
+                if (mName == null) {
+                    mName = mPhoneNumber;
+                }
+            }
+        }
+
+        if (mName == null) {
+            mName = "";
+        }
+        checkPostion(cursor);
+    }
+//根据鼠标的位置设置标记和位置
+    private void checkPostion(Cursor cursor) {
+        //初始化几个标记
+        mIsLastItem = cursor.isLast() ? true : false;
+        mIsFirstItem = cursor.isFirst() ? true : false;
+        mIsOnlyOneItem = (cursor.getCount() == 1);
+        //初始化“多重子文件”、“单一子文件”两个标记
+        mIsMultiNotesFollowingFolder = false;
+        mIsOneNoteFollowingFolder = false;
+//主要是设置上述两个标记
+        if (mType == Notes.TYPE_NOTE && !mIsFirstItem) {//若是note格式并且不是第一个元素
+            int position = cursor.getPosition();
+            if (cursor.moveToPrevious()) {//获取光标位置后看上一行
+                if (cursor.getInt(TYPE_COLUMN) == Notes.TYPE_FOLDER
+                        || cursor.getInt(TYPE_COLUMN) == Notes.TYPE_SYSTEM) {//若光标满足系统或note格式
+                    if (cursor.getCount() > (position + 1)) {
+                        mIsMultiNotesFollowingFolder = true;//若是数据行数大于当前位置+1则设置成功
+                    } else {
+                        mIsOneNoteFollowingFolder = true;//否则单一文件夹标记为true
+                    }
+                }
+                if (!cursor.moveToNext()) {//若不能再往下走则报错
+                    throw new IllegalStateException("cursor move to previous but can't move back");
+                }
+            }
+        }
+    }
+//以下均为获取标记
+    public boolean isOneFollowingFolder() {
+        return mIsOneNoteFollowingFolder;
+    }
+
+    public boolean isMultiFollowingFolder() {
+        return mIsMultiNotesFollowingFolder;
+    }
+
+    public boolean isLast() {
+        return mIsLastItem;
+    }
+
+    public String getCallName() {
+        return mName;
+    }
+
+    public boolean isFirst() {
+        return mIsFirstItem;
+    }
+
+    public boolean isSingle() {
+        return mIsOnlyOneItem;
+    }
+
+    public long getId() {
+        return mId;
+    }
+
+    public long getAlertDate() {
+        return mAlertDate;
+    }
+
+    public long getCreatedDate() {
+        return mCreatedDate;
+    }
+
+    public boolean hasAttachment() {
+        return mHasAttachment;
+    }
+
+    public long getModifiedDate() {
+        return mModifiedDate;
+    }
+
+    public int getBgColorId() {
+        return mBgColorId;
+    }
+
+    public long getParentId() {
+        return mParentId;
+    }
+
+    public int getNotesCount() {
+        return mNotesCount;
+    }
+
+    public long getFolderId () {
+        return mParentId;
+    }
+
+    public int getType() {
+        return mType;
+    }
+
+    public int getWidgetType() {
+        return mWidgetType;
+    }
+
+    public int getWidgetId() {
+        return mWidgetId;
+    }
+
+    public String getSnippet() {
+        return mSnippet;
+    }
+
+    public boolean hasAlert() {
+        return (mAlertDate > 0);
+    }
+//若数据父id为保存至文件夹模式的id且满足电话号码单元不为空，则isCallRecord为true
+    public boolean isCallRecord() {
+        return (mParentId == Notes.ID_CALL_RECORD_FOLDER && !TextUtils.isEmpty(mPhoneNumber));
+    }
+
+    public static int getNoteType(Cursor cursor) {
+        return cursor.getInt(TYPE_COLUMN);
+    }
+}

NoteWidgetProvider.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.widget;
+import android.app.PendingIntent;
+import android.appwidget.AppWidgetManager;
+import android.appwidget.AppWidgetProvider;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.Intent;
+import android.database.Cursor;
+import android.util.Log;
+import android.widget.RemoteViews;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.tool.ResourceParser;
+import net.micode.notes.ui.NoteEditActivity;
+import net.micode.notes.ui.NotesListActivity;
+
+public abstract class NoteWidgetProvider extends AppWidgetProvider {
+    // 定义常量数组，用于查询数据库中的列
+    public static final String [] PROJECTION = new String [] {
+        NoteColumns.ID,
+        NoteColumns.BG_COLOR_ID,
+        NoteColumns.SNIPPET
+    };
+    // 定义常量，表示列索引
+    public static final int COLUMN_ID           = 0;
+    public static final int COLUMN_BG_COLOR_ID  = 1;
+    public static final int COLUMN_SNIPPET      = 2;
+    // 定义日志标签
+    private static final String TAG = "NoteWidgetProvider";
+    // 当小部件被删除时调用的方法
+    @Override
+    public void onDeleted(Context context, int[] appWidgetIds) {
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        for (int i = 0; i < appWidgetIds.length; i++) {
+            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,
+                    values,
+                    NoteColumns.WIDGET_ID + "=?",
+                    new String[] { String.valueOf(appWidgetIds[i])});
+        }
+    }
+    // 获取小部件信息的方法
+    private Cursor getNoteWidgetInfo(Context context, int widgetId) {
+        return context.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+                PROJECTION,
+                NoteColumns.WIDGET_ID + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+                new String[] { String.valueOf(widgetId), String.valueOf(Notes.ID_TRASH_FOLER) },
+                null);
+    }
+    // 更新小部件的方法
+    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        update(context, appWidgetManager, appWidgetIds, false);
+    }
+    // 私有的更新方法，支持隐私模式
+    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,
+            boolean privacyMode) {
+        for (int i = 0; i < appWidgetIds.length; i++) {
+            if (appWidgetIds[i] != AppWidgetManager.INVALID_APPWIDGET_ID) {
+                int bgId = ResourceParser.getDefaultBgId(context);
+                String snippet = "";
+                Intent intent = new Intent(context, NoteEditActivity.class);
+                intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
+                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_ID, appWidgetIds[i]);
+                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_TYPE, getWidgetType());
+
+                Cursor c = getNoteWidgetInfo(context, appWidgetIds[i]);
+                if (c != null && c.moveToFirst()) {
+                    if (c.getCount() > 1) {
+                        Log.e(TAG, "Multiple message with same widget id:" + appWidgetIds[i]);
+                        c.close();
+                        return;
+                    }
+                    snippet = c.getString(COLUMN_SNIPPET);
+                    bgId = c.getInt(COLUMN_BG_COLOR_ID);
+                    intent.putExtra(Intent.EXTRA_UID, c.getLong(COLUMN_ID));
+                    intent.setAction(Intent.ACTION_VIEW);
+                } else {
+                    snippet = context.getResources().getString(R.string.widget_havenot_content);
+                    intent.setAction(Intent.ACTION_INSERT_OR_EDIT);
+                }
+
+                if (c != null) {
+                    c.close();
+                }
+
+                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());
+                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));
+                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);
+                /**
+                 * Generate the pending intent to start host for the widget
+                 */
+                PendingIntent pendingIntent = null;
+                if (privacyMode) {
+                    rv.setTextViewText(R.id.widget_text,
+                            context.getString(R.string.widget_under_visit_mode));
+                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], new Intent(
+                            context, NotesListActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
+                } else {
+                    rv.setTextViewText(R.id.widget_text, snippet);
+                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], intent,
+                            PendingIntent.FLAG_UPDATE_CURRENT);
+                }
+
+                rv.setOnClickPendingIntent(R.id.widget_text, pendingIntent);
+                appWidgetManager.updateAppWidget(appWidgetIds[i], rv);
+            }
+        }
+    }
+    // 抽象方法，获取背景资源ID
+    protected abstract int getBgResourceId(int bgId);
+    // 抽象方法，获取布局资源ID
+    protected abstract int getLayoutId();
+    // 抽象方法，获取小部件类型
+    protected abstract int getWidgetType();
+}

NoteWidgetProvider_2x.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.widget;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.ResourceParser;
+
+// 继承自NoteWidgetProvider的子类，用于处理2x大小的便笺部件
+public class NoteWidgetProvider_2x extends NoteWidgetProvider {
+// 当部件更新时调用此方法
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        // 调用父类的update方法进行更新
+        super.update(context, appWidgetManager, appWidgetIds);
+    }
+// 获取布局资源ID的方法，返回2x大小的便笺部件布局资源ID
+    @Override
+    protected int getLayoutId() {
+        return R.layout.widget_2x;
+    }
+// 获取背景资源ID的方法，根据传入的背景ID返回对应的2x大小的背景资源ID
+    @Override
+    protected int getBgResourceId(int bgId) {
+        return ResourceParser.WidgetBgResources.getWidget2xBgResource(bgId);
+    }
+// 获取部件类型的方法，返回2x大小的便笺部件类型
+    @Override
+    protected int getWidgetType() {
+        return Notes.TYPE_WIDGET_2X;
+    }
+}

NoteWidgetProvider_4x.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.widget;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.ResourceParser;
+
+// 定义一个名为NoteWidgetProvider_4x的类，继承自NoteWidgetProvider类
+public class NoteWidgetProvider_4x extends NoteWidgetProvider {
+    // 重写onUpdate方法，用于更新小部件
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        // 调用父类的update方法进行更新
+        super.update(context, appWidgetManager, appWidgetIds);
+    }
+// 获取布局资源ID的方法，返回4x大小的便笺部件布局资源ID
+    protected int getLayoutId() {
+        return R.layout.widget_4x;
+    }
+// 获取背景资源ID的方法，根据传入的背景ID返回对应的4x大小的背景资源ID
+    @Override
+    protected int getBgResourceId(int bgId) {
+        return ResourceParser.WidgetBgResources.getWidget4xBgResource(bgId);
+    }
+// 获取部件类型的方法，返回4x大小的便笺部件类型
+    @Override
+    protected int getWidgetType() {
+        return Notes.TYPE_WIDGET_4X;
+    }
+}

Notes.java

@@ -0,0 +1,315 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.net.Uri;
+// Notes 类中定义了很多常量，这些常量大多是int型和string型
+public class Notes {
+    public static final String AUTHORITY = "micode_notes";
+    public static final String TAG = "Notes";
+    //以下三个常量对NoteColumns.TYPE的值进行设置时会用到
+    public static final int TYPE_NOTE     = 0;
+    public static final int TYPE_FOLDER   = 1;
+    public static final int TYPE_SYSTEM   = 2;
+
+    /**
+     * Following IDs are system folders' identifiers
+     * {@link Notes#ID_ROOT_FOLDER } is default folder
+     * {@link Notes#ID_TEMPARAY_FOLDER } is for notes belonging no folder
+     * {@link Notes#ID_CALL_RECORD_FOLDER} is to store call records
+     */
+    //以下ID是系统文件夹的标识符
+    public static final int ID_ROOT_FOLDER = 0;
+    public static final int ID_TEMPARAY_FOLDER = -1;
+    public static final int ID_CALL_RECORD_FOLDER = -2;
+    public static final int ID_TRASH_FOLER = -3;
+
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date";
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date";
+
+    public static final int TYPE_WIDGET_INVALIDE      = -1;
+    public static final int TYPE_WIDGET_2X            = 0;
+    public static final int TYPE_WIDGET_4X            = 1;
+
+    public static class DataConstants {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;
+    }
+
+    /**
+     * Uri to query all notes and folders
+     */
+    //用于查询所有便签和文件夹uri
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");//定义查询便签和文件夹的指针。
+
+    /**
+     * Uri to query data
+     */
+    //用于查询数据uri
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");//定义查找数据的指针。
+
+ // 定义NoteColumns的常量,用于后面创建数据库的表头
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        //行的唯一ID
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        //便签或文件夹的父级ID
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        //以为便签或文件夹创建数据
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        //最新修改日期
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        //警报日期
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        //便签的文件夹名称或文本内容
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        //小部件ID
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        //小部件类型
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        //背景颜色的ID
+        public static final String BG_COLOR_ID = "bg_color_id";
+
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+        //对于文本便签，它没有附件；对于multi-media便签，它至少有一个附件
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        //文件夹的便签计数
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        //类型：文件夹或便签
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        //上一个同步ID
+        public static final String SYNC_ID = "sync_id";//同步
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        //标志表示是否本地修改
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        //移动到临时文件夹之前的原始父ID
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        //gtask id，类型为文本
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";
+    }//这些常量主要是定义便签的属性的。
+// 定义DataColumns的常量,用于后面创建数据库的表头
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        //行的唯一ID
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        //此行表示的项的MIME类型
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        //要注明此数据所属的引用id
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        //已为便签或文件夹创建数据
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        //最新修改日期
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        //数据的内容
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        //通用数据列，含义是{@link #MIMETYPE}特定的，用于合并数据类型
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        //通用数据列，含义是{@link #MIMETYPE}特定的，用于合并数据类型
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        //通用数据列，含义是{@link #MIMETYPE}特定的，用于文本数据类型
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        //通用数据列，含义是{@link #MIMETYPE}特定的，用于文本数据类型
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        //通用数据列，含义是{@link #MIMETYPE}特定的，用于文本数据类型
+        public static final String DATA5 = "data5";
+    }//主要是定义存储便签内容数据的
+
+    public static final class TextNote implements DataColumns {
+        /**
+         * Mode to indicate the text in check list mode or not
+         * <P> Type: Integer 1:check list mode 0: normal mode </P>
+         */
+        //模式：指示文本是否处于检查列表模式
+        public static final String MODE = DATA1;
+
+        public static final int MODE_CHECK_LIST = 1;
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }//文本内容的数据结构
+
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        //此纪录的调用日期
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        //此纪录的电话号码
+        public static final String PHONE_NUMBER = DATA3;
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }//电话内容的数据结构
+}

NotesDatabaseHelper.java

@@ -0,0 +1,364 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.content.ContentValues;//就是用于保存一些数据（string boolean byte double float int long short ...）信息，这些信息可以被数据库操作时使用。
+import android.content.Context;//加载和访问资源。（android中主要是这两个功能，但是这里具体不清楚）
+import android.database.sqlite.SQLiteDatabase;;//主要提供了对应于添加、删除、更新、查询的操作方法： insert()、delete()、update()和query()。配合content.values
+import android.database.sqlite.SQLiteOpenHelper;//用来管理数据的创建和版本更新
+import android.util.Log;
+
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+//数据库操作，用SQLOpenhelper,对一些note和文件进行数据库的操作，比如删除文件后，将文件里的note也相应删除
+
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    private static final String DB_NAME = "note.db";
+
+    private static final int DB_VERSION = 4;
+
+    public interface TABLE {//接口，分成note和data，在后面的程序里分别使用过
+        public static final String NOTE = "note";
+
+        public static final String DATA = "data";
+    }
+
+    private static final String TAG = "NotesDatabaseHelper";
+
+    private static NotesDatabaseHelper mInstance;
+
+    private static final String CREATE_NOTE_TABLE_SQL =
+        "CREATE TABLE " + TABLE.NOTE + "(" +
+            NoteColumns.ID + " INTEGER PRIMARY KEY," +
+            NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
+            NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
+        ")";//数据库中需要存储的项目的名称，就相当于创建一个表格的表头的内容。
+
+    private static final String CREATE_DATA_TABLE_SQL =
+        "CREATE TABLE " + TABLE.DATA + "(" +
+            DataColumns.ID + " INTEGER PRIMARY KEY," +
+            DataColumns.MIME_TYPE + " TEXT NOT NULL," +
+            DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA1 + " INTEGER," +
+            DataColumns.DATA2 + " INTEGER," +
+            DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
+        ")";//和上面的功能一样，主要是存储的项目不同
+
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";//存储便签编号的一个数据表格
+
+    /**
+     * Increase folder's note count when move note to the folder
+     */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_update "+
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";//在文件夹中移入一个Note之后需要更改的数据的表格。
+
+    /**
+     * Decrease folder's note count when move note from folder
+     */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_update " +
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+        " END";//在文件夹中移除一个Note之后需要更改的数据的表格。
+
+    /**
+     * Increase folder's note count when insert new note to the folder
+     */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_insert " +
+        " AFTER INSERT ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";//在文件夹中插入一个Note之后需要更改的数据的表格。
+
+    /**
+     * Decrease folder's note count when delete note from the folder
+     */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+        " END";//在文件夹中删除一个Note之后需要更改的数据的表格。
+    /**
+     * Update note's content when insert data with type {@link DataConstants#NOTE}
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_insert " +
+        " AFTER INSERT ON " + TABLE.DATA +
+        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";//在文件夹中对一个Note导入新的数据之后需要更改的数据的表格。
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has changed
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_update " +
+        " AFTER UPDATE ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";//Note数据被修改之后需要更改的数据的表格。
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has deleted
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_delete " +
+        " AFTER delete ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=''" +
+        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+        " END";//Note数据被删除之后需要更改的数据的表格。
+
+    /**
+     * Delete datas belong to note which has been deleted
+     */
+    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER delete_data_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.DATA +
+        "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
+        " END";//删除已删除的便签的数据后需要更改的数据的表格
+
+    /**
+     * Delete notes belong to folder which has been deleted
+     */
+    private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER folder_delete_notes_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.NOTE +
+        "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+        " END";//删除已删除的文件夹的便签后需要更改的数据的表格
+
+    /**
+     * Move notes belong to folder which has been moved to trash folder
+     */
+    private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
+        "CREATE TRIGGER folder_move_notes_on_trash " +
+        " AFTER UPDATE ON " + TABLE.NOTE +
+        " WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+        "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+        " END";//还原垃圾桶中便签后需要更改的数据的表格
+
+    public NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }//构造函数，传入数据库的名称和版本
+
+    public void createNoteTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_NOTE_TABLE_SQL);
+        reCreateNoteTableTriggers(db);
+        createSystemFolder(db);
+        Log.d(TAG, "note table has been created");
+    }//创建表格（用来存储标签属性）
+
+    private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS delete_data_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
+
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
+        db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
+        db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
+        db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
+    }//execSQL是数据库操作的API，主要是更改行为的SQL语句
+    //在这里主要是用来重新创建上述定义的表格用的，先删除原来有的数据库的触发器再重新创建新的数据库
+
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+        /**
+         * call record foler for call notes
+         */
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * root folder which is default folder
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * temporary folder which is used for moving note
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * create trash folder
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+//创建几个系统文件夹
+    public void createDataTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_DATA_TABLE_SQL);
+        reCreateDataTableTriggers(db);
+        db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
+        Log.d(TAG, "data table has been created");
+    }//创建表格（用来存储标签内容）
+
+    private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");
+
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER);
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER);
+        db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
+    }//同上面的execSQL
+
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }/**上网查是为解决同一时刻只能有一个线程执行
+    *在写程序库代码时，有时有一个类需要被所有的其他类使用，
+    但又要求这个类只能被实例化一次，是个服务类，定义一次，其它类使用同一个这个类的实例*/
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createNoteTable(db);
+        createDataTable(db);
+    }//实现两个表格（上面创建的两个表格）
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // this upgrade including the upgrade from v2 to v3
+            oldVersion++;
+        }
+
+        if (oldVersion == 2 && !skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+
+        if (oldVersion != newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }//数据库版本的更新（数据库内容的更改）
+
+    private void upgradeToV2(SQLiteDatabase db) {
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
+        createNoteTable(db);
+        createDataTable(db);
+    }//更新到V2版本
+
+    private void upgradeToV3(SQLiteDatabase db) {
+        // drop unused triggers
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+        // add a column for gtask id
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+        // add a trash system folder
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }//更新到V3版本
+
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");
+    }//更新到V4版本
+}

NotesListActivity.java

@@ -0,0 +1,954 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.appwidget.AppWidgetManager;
+import android.content.AsyncQueryHandler;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.database.Cursor;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.preference.PreferenceManager;
+import android.text.Editable;
+import android.text.TextUtils;
+import android.text.TextWatcher;
+import android.util.Log;
+import android.view.ActionMode;
+import android.view.ContextMenu;
+import android.view.ContextMenu.ContextMenuInfo;
+import android.view.Display;
+import android.view.HapticFeedbackConstants;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.MenuItem.OnMenuItemClickListener;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnCreateContextMenuListener;
+import android.view.View.OnTouchListener;
+import android.view.inputmethod.InputMethodManager;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemClickListener;
+import android.widget.AdapterView.OnItemLongClickListener;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.ListView;
+import android.widget.PopupMenu;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.remote.GTaskSyncService;
+import net.micode.notes.model.WorkingNote;
+import net.micode.notes.tool.BackupUtils;
+import net.micode.notes.tool.DataUtils;
+import net.micode.notes.tool.ResourceParser;
+import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
+import net.micode.notes.widget.NoteWidgetProvider_2x;
+import net.micode.notes.widget.NoteWidgetProvider_4x;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.HashSet;
+
+public class NotesListActivity extends Activity implements OnClickListener, OnItemLongClickListener {
+    private static final int FOLDER_NOTE_LIST_QUERY_TOKEN = 0;
+
+    private static final int FOLDER_LIST_QUERY_TOKEN      = 1;
+
+    private static final int MENU_FOLDER_DELETE = 0;
+
+    private static final int MENU_FOLDER_VIEW = 1;
+
+    private static final int MENU_FOLDER_CHANGE_NAME = 2;
+
+    private static final String PREFERENCE_ADD_INTRODUCTION = "net.micode.notes.introduction";
+
+    private enum ListEditState {
+        NOTE_LIST, SUB_FOLDER, CALL_RECORD_FOLDER
+    };
+
+    private ListEditState mState;
+
+    private BackgroundQueryHandler mBackgroundQueryHandler;
+
+    private NotesListAdapter mNotesListAdapter;
+
+    private ListView mNotesListView;
+
+    private Button mAddNewNote;
+
+    private boolean mDispatch;
+
+    private int mOriginY;
+
+    private int mDispatchY;
+
+    private TextView mTitleBar;
+
+    private long mCurrentFolderId;
+
+    private ContentResolver mContentResolver;
+
+    private ModeCallback mModeCallBack;
+
+    private static final String TAG = "NotesListActivity";
+
+    public static final int NOTES_LISTVIEW_SCROLL_RATE = 30;
+
+    private NoteItemData mFocusNoteDataItem;
+
+    private static final String NORMAL_SELECTION = NoteColumns.PARENT_ID + "=?";
+
+    private static final String ROOT_FOLDER_SELECTION = "(" + NoteColumns.TYPE + "<>"
+            + Notes.TYPE_SYSTEM + " AND " + NoteColumns.PARENT_ID + "=?)" + " OR ("
+            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER + " AND "
+            + NoteColumns.NOTES_COUNT + ">0)";
+
+    private final static int REQUEST_CODE_OPEN_NODE = 102;
+    private final static int REQUEST_CODE_NEW_NODE  = 103;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.note_list);
+        initResources();
+
+        /**
+         * Insert an introduction when user firstly use this application
+         */
+        setAppInfoFromRawRes();
+    }
+
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (resultCode == RESULT_OK
+                && (requestCode == REQUEST_CODE_OPEN_NODE || requestCode == REQUEST_CODE_NEW_NODE)) {
+            mNotesListAdapter.changeCursor(null);
+        } else {
+            super.onActivityResult(requestCode, resultCode, data);
+        }
+    }
+
+    private void setAppInfoFromRawRes() {
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
+        if (!sp.getBoolean(PREFERENCE_ADD_INTRODUCTION, false)) {
+            StringBuilder sb = new StringBuilder();
+            InputStream in = null;
+            try {
+                 in = getResources().openRawResource(R.raw.introduction);
+                if (in != null) {
+                    InputStreamReader isr = new InputStreamReader(in);
+                    BufferedReader br = new BufferedReader(isr);
+                    char [] buf = new char[1024];
+                    int len = 0;
+                    while ((len = br.read(buf)) > 0) {
+                        sb.append(buf, 0, len);
+                    }
+                } else {
+                    Log.e(TAG, "Read introduction file error");
+                    return;
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+                return;
+            } finally {
+                if(in != null) {
+                    try {
+                        in.close();
+                    } catch (IOException e) {
+                        // TODO Auto-generated catch block
+                        e.printStackTrace();
+                    }
+                }
+            }
+
+            WorkingNote note = WorkingNote.createEmptyNote(this, Notes.ID_ROOT_FOLDER,
+                    AppWidgetManager.INVALID_APPWIDGET_ID, Notes.TYPE_WIDGET_INVALIDE,
+                    ResourceParser.RED);
+            note.setWorkingText(sb.toString());
+            if (note.saveNote()) {
+                sp.edit().putBoolean(PREFERENCE_ADD_INTRODUCTION, true).commit();
+            } else {
+                Log.e(TAG, "Save introduction note error");
+                return;
+            }
+        }
+    }
+
+    @Override
+    protected void onStart() {
+        super.onStart();
+        startAsyncNotesListQuery();
+    }
+
+    private void initResources() {
+        mContentResolver = this.getContentResolver();
+        mBackgroundQueryHandler = new BackgroundQueryHandler(this.getContentResolver());
+        mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+        mNotesListView = (ListView) findViewById(R.id.notes_list);
+        mNotesListView.addFooterView(LayoutInflater.from(this).inflate(R.layout.note_list_footer, null),
+                null, false);
+        mNotesListView.setOnItemClickListener(new OnListItemClickListener());
+        mNotesListView.setOnItemLongClickListener(this);
+        mNotesListAdapter = new NotesListAdapter(this);
+        mNotesListView.setAdapter(mNotesListAdapter);
+        mAddNewNote = (Button) findViewById(R.id.btn_new_note);
+        mAddNewNote.setOnClickListener(this);
+        mAddNewNote.setOnTouchListener(new NewNoteOnTouchListener());
+        mDispatch = false;
+        mDispatchY = 0;
+        mOriginY = 0;
+        mTitleBar = (TextView) findViewById(R.id.tv_title_bar);
+        mState = ListEditState.NOTE_LIST;
+        mModeCallBack = new ModeCallback();
+    }
+
+    private class ModeCallback implements ListView.MultiChoiceModeListener, OnMenuItemClickListener {
+        private DropdownMenu mDropDownMenu;
+        private ActionMode mActionMode;
+        private MenuItem mMoveMenu;
+
+        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
+            getMenuInflater().inflate(R.menu.note_list_options, menu);
+            menu.findItem(R.id.delete).setOnMenuItemClickListener(this);
+            mMoveMenu = menu.findItem(R.id.move);
+            if (mFocusNoteDataItem.getParentId() == Notes.ID_CALL_RECORD_FOLDER
+                    || DataUtils.getUserFolderCount(mContentResolver) == 0) {
+                mMoveMenu.setVisible(false);
+            } else {
+                mMoveMenu.setVisible(true);
+                mMoveMenu.setOnMenuItemClickListener(this);
+            }
+            mActionMode = mode;
+            mNotesListAdapter.setChoiceMode(true);
+            mNotesListView.setLongClickable(false);
+            mAddNewNote.setVisibility(View.GONE);
+
+            View customView = LayoutInflater.from(NotesListActivity.this).inflate(
+                    R.layout.note_list_dropdown_menu, null);
+            mode.setCustomView(customView);
+            mDropDownMenu = new DropdownMenu(NotesListActivity.this,
+                    (Button) customView.findViewById(R.id.selection_menu),
+                    R.menu.note_list_dropdown);
+            mDropDownMenu.setOnDropdownMenuItemClickListener(new PopupMenu.OnMenuItemClickListener(){
+                public boolean onMenuItemClick(MenuItem item) {
+                    mNotesListAdapter.selectAll(!mNotesListAdapter.isAllSelected());
+                    updateMenu();
+                    return true;
+                }
+
+            });
+            return true;
+        }
+
+        private void updateMenu() {
+            int selectedCount = mNotesListAdapter.getSelectedCount();
+            // Update dropdown menu
+            String format = getResources().getString(R.string.menu_select_title, selectedCount);
+            mDropDownMenu.setTitle(format);
+            MenuItem item = mDropDownMenu.findItem(R.id.action_select_all);
+            if (item != null) {
+                if (mNotesListAdapter.isAllSelected()) {
+                    item.setChecked(true);
+                    item.setTitle(R.string.menu_deselect_all);
+                } else {
+                    item.setChecked(false);
+                    item.setTitle(R.string.menu_select_all);
+                }
+            }
+        }
+
+        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        public void onDestroyActionMode(ActionMode mode) {
+            mNotesListAdapter.setChoiceMode(false);
+            mNotesListView.setLongClickable(true);
+            mAddNewNote.setVisibility(View.VISIBLE);
+        }
+
+        public void finishActionMode() {
+            mActionMode.finish();
+        }
+
+        public void onItemCheckedStateChanged(ActionMode mode, int position, long id,
+                boolean checked) {
+            mNotesListAdapter.setCheckedItem(position, checked);
+            updateMenu();
+        }
+
+        public boolean onMenuItemClick(MenuItem item) {
+            if (mNotesListAdapter.getSelectedCount() == 0) {
+                Toast.makeText(NotesListActivity.this, getString(R.string.menu_select_none),
+                        Toast.LENGTH_SHORT).show();
+                return true;
+            }
+
+            switch (item.getItemId()) {
+                case R.id.delete:
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(getString(R.string.alert_title_delete));
+                    builder.setIcon(android.R.drawable.ic_dialog_alert);
+                    builder.setMessage(getString(R.string.alert_message_delete_notes,
+                                             mNotesListAdapter.getSelectedCount()));
+                    builder.setPositiveButton(android.R.string.ok,
+                                             new DialogInterface.OnClickListener() {
+                                                 public void onClick(DialogInterface dialog,
+                                                         int which) {
+                                                     batchDelete();
+                                                 }
+                                             });
+                    builder.setNegativeButton(android.R.string.cancel, null);
+                    builder.show();
+                    break;
+                case R.id.move:
+                    startQueryDestinationFolders();
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+    }
+
+    private class NewNoteOnTouchListener implements OnTouchListener {
+
+        public boolean onTouch(View v, MotionEvent event) {
+            switch (event.getAction()) {
+                case MotionEvent.ACTION_DOWN: {
+                    Display display = getWindowManager().getDefaultDisplay();
+                    int screenHeight = display.getHeight();
+                    int newNoteViewHeight = mAddNewNote.getHeight();
+                    int start = screenHeight - newNoteViewHeight;
+                    int eventY = start + (int) event.getY();
+                    /**
+                     * Minus TitleBar's height
+                     */
+                    if (mState == ListEditState.SUB_FOLDER) {
+                        eventY -= mTitleBar.getHeight();
+                        start -= mTitleBar.getHeight();
+                    }
+                    /**
+                     * HACKME:When click the transparent part of "New Note" button, dispatch
+                     * the event to the list view behind this button. The transparent part of
+                     * "New Note" button could be expressed by formula y=-0.12x+94（Unit:pixel）
+                     * and the line top of the button. The coordinate based on left of the "New
+                     * Note" button. The 94 represents maximum height of the transparent part.
+                     * Notice that, if the background of the button changes, the formula should
+                     * also change. This is very bad, just for the UI designer's strong requirement.
+                     */
+                    if (event.getY() < (event.getX() * (-0.12) + 94)) {
+                        View view = mNotesListView.getChildAt(mNotesListView.getChildCount() - 1
+                                - mNotesListView.getFooterViewsCount());
+                        if (view != null && view.getBottom() > start
+                                && (view.getTop() < (start + 94))) {
+                            mOriginY = (int) event.getY();
+                            mDispatchY = eventY;
+                            event.setLocation(event.getX(), mDispatchY);
+                            mDispatch = true;
+                            return mNotesListView.dispatchTouchEvent(event);
+                        }
+                    }
+                    break;
+                }
+                case MotionEvent.ACTION_MOVE: {
+                    if (mDispatch) {
+                        mDispatchY += (int) event.getY() - mOriginY;
+                        event.setLocation(event.getX(), mDispatchY);
+                        return mNotesListView.dispatchTouchEvent(event);
+                    }
+                    break;
+                }
+                default: {
+                    if (mDispatch) {
+                        event.setLocation(event.getX(), mDispatchY);
+                        mDispatch = false;
+                        return mNotesListView.dispatchTouchEvent(event);
+                    }
+                    break;
+                }
+            }
+            return false;
+        }
+
+    };
+
+    private void startAsyncNotesListQuery() {
+        String selection = (mCurrentFolderId == Notes.ID_ROOT_FOLDER) ? ROOT_FOLDER_SELECTION
+                : NORMAL_SELECTION;
+        mBackgroundQueryHandler.startQuery(FOLDER_NOTE_LIST_QUERY_TOKEN, null,
+                Notes.CONTENT_NOTE_URI, NoteItemData.PROJECTION, selection, new String[] {
+                    String.valueOf(mCurrentFolderId)
+                }, NoteColumns.TYPE + " DESC," + NoteColumns.MODIFIED_DATE + " DESC");
+    }
+
+    private final class BackgroundQueryHandler extends AsyncQueryHandler {
+        public BackgroundQueryHandler(ContentResolver contentResolver) {
+            super(contentResolver);
+        }
+
+        @Override
+        protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
+            switch (token) {
+                case FOLDER_NOTE_LIST_QUERY_TOKEN:
+                    mNotesListAdapter.changeCursor(cursor);
+                    break;
+                case FOLDER_LIST_QUERY_TOKEN:
+                    if (cursor != null && cursor.getCount() > 0) {
+                        showFolderListMenu(cursor);
+                    } else {
+                        Log.e(TAG, "Query folder failed");
+                    }
+                    break;
+                default:
+                    return;
+            }
+        }
+    }
+
+    private void showFolderListMenu(Cursor cursor) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+        builder.setTitle(R.string.menu_title_select_folder);
+        final FoldersListAdapter adapter = new FoldersListAdapter(this, cursor);
+        builder.setAdapter(adapter, new DialogInterface.OnClickListener() {
+
+            public void onClick(DialogInterface dialog, int which) {
+                DataUtils.batchMoveToFolder(mContentResolver,
+                        mNotesListAdapter.getSelectedItemIds(), adapter.getItemId(which));
+                Toast.makeText(
+                        NotesListActivity.this,
+                        getString(R.string.format_move_notes_to_folder,
+                                mNotesListAdapter.getSelectedCount(),
+                                adapter.getFolderName(NotesListActivity.this, which)),
+                        Toast.LENGTH_SHORT).show();
+                mModeCallBack.finishActionMode();
+            }
+        });
+        builder.show();
+    }
+
+    private void createNewNote() {
+        Intent intent = new Intent(this, NoteEditActivity.class);
+        intent.setAction(Intent.ACTION_INSERT_OR_EDIT);
+        intent.putExtra(Notes.INTENT_EXTRA_FOLDER_ID, mCurrentFolderId);
+        this.startActivityForResult(intent, REQUEST_CODE_NEW_NODE);
+    }
+
+    private void batchDelete() {
+        new AsyncTask<Void, Void, HashSet<AppWidgetAttribute>>() {
+            protected HashSet<AppWidgetAttribute> doInBackground(Void... unused) {
+                HashSet<AppWidgetAttribute> widgets = mNotesListAdapter.getSelectedWidget();
+                if (!isSyncMode()) {
+                    // if not synced, delete notes directly
+                    if (DataUtils.batchDeleteNotes(mContentResolver, mNotesListAdapter
+                            .getSelectedItemIds())) {
+                    } else {
+                        Log.e(TAG, "Delete notes error, should not happens");
+                    }
+                } else {
+                    // in sync mode, we'll move the deleted note into the trash
+                    // folder
+                    if (!DataUtils.batchMoveToFolder(mContentResolver, mNotesListAdapter
+                            .getSelectedItemIds(), Notes.ID_TRASH_FOLER)) {
+                        Log.e(TAG, "Move notes to trash folder error, should not happens");
+                    }
+                }
+                return widgets;
+            }
+
+            @Override
+            protected void onPostExecute(HashSet<AppWidgetAttribute> widgets) {
+                if (widgets != null) {
+                    for (AppWidgetAttribute widget : widgets) {
+                        if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                                && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
+                            updateWidget(widget.widgetId, widget.widgetType);
+                        }
+                    }
+                }
+                mModeCallBack.finishActionMode();
+            }
+        }.execute();
+    }
+
+    private void deleteFolder(long folderId) {
+        if (folderId == Notes.ID_ROOT_FOLDER) {
+            Log.e(TAG, "Wrong folder id, should not happen " + folderId);
+            return;
+        }
+
+        HashSet<Long> ids = new HashSet<Long>();
+        ids.add(folderId);
+        HashSet<AppWidgetAttribute> widgets = DataUtils.getFolderNoteWidget(mContentResolver,
+                folderId);
+        if (!isSyncMode()) {
+            // if not synced, delete folder directly
+            DataUtils.batchDeleteNotes(mContentResolver, ids);
+        } else {
+            // in sync mode, we'll move the deleted folder into the trash folder
+            DataUtils.batchMoveToFolder(mContentResolver, ids, Notes.ID_TRASH_FOLER);
+        }
+        if (widgets != null) {
+            for (AppWidgetAttribute widget : widgets) {
+                if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                        && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
+                    updateWidget(widget.widgetId, widget.widgetType);
+                }
+            }
+        }
+    }
+
+    private void openNode(NoteItemData data) {
+        Intent intent = new Intent(this, NoteEditActivity.class);
+        intent.setAction(Intent.ACTION_VIEW);
+        intent.putExtra(Intent.EXTRA_UID, data.getId());
+        this.startActivityForResult(intent, REQUEST_CODE_OPEN_NODE);
+    }
+
+    private void openFolder(NoteItemData data) {
+        mCurrentFolderId = data.getId();
+        startAsyncNotesListQuery();
+        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
+            mState = ListEditState.CALL_RECORD_FOLDER;
+            mAddNewNote.setVisibility(View.GONE);
+        } else {
+            mState = ListEditState.SUB_FOLDER;
+        }
+        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
+            mTitleBar.setText(R.string.call_record_folder_name);
+        } else {
+            mTitleBar.setText(data.getSnippet());
+        }
+        mTitleBar.setVisibility(View.VISIBLE);
+    }
+
+    public void onClick(View v) {
+        switch (v.getId()) {
+            case R.id.btn_new_note:
+                createNewNote();
+                break;
+            default:
+                break;
+        }
+    }
+
+    private void showSoftInput() {
+        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
+        if (inputMethodManager != null) {
+            inputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
+        }
+    }
+
+    private void hideSoftInput(View view) {
+        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
+        inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
+    }
+
+    private void showCreateOrModifyFolderDialog(final boolean create) {
+        final AlertDialog.Builder builder = new AlertDialog.Builder(this);
+        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_text, null);
+        final EditText etName = (EditText) view.findViewById(R.id.et_foler_name);
+        showSoftInput();
+        if (!create) {
+            if (mFocusNoteDataItem != null) {
+                etName.setText(mFocusNoteDataItem.getSnippet());
+                builder.setTitle(getString(R.string.menu_folder_change_name));
+            } else {
+                Log.e(TAG, "The long click data item is null");
+                return;
+            }
+        } else {
+            etName.setText("");
+            builder.setTitle(this.getString(R.string.menu_create_folder));
+        }
+
+        builder.setPositiveButton(android.R.string.ok, null);
+        builder.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
+            public void onClick(DialogInterface dialog, int which) {
+                hideSoftInput(etName);
+            }
+        });
+
+        final Dialog dialog = builder.setView(view).show();
+        final Button positive = (Button)dialog.findViewById(android.R.id.button1);
+        positive.setOnClickListener(new OnClickListener() {
+            public void onClick(View v) {
+                hideSoftInput(etName);
+                String name = etName.getText().toString();
+                if (DataUtils.checkVisibleFolderName(mContentResolver, name)) {
+                    Toast.makeText(NotesListActivity.this, getString(R.string.folder_exist, name),
+                            Toast.LENGTH_LONG).show();
+                    etName.setSelection(0, etName.length());
+                    return;
+                }
+                if (!create) {
+                    if (!TextUtils.isEmpty(name)) {
+                        ContentValues values = new ContentValues();
+                        values.put(NoteColumns.SNIPPET, name);
+                        values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+                        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+                        mContentResolver.update(Notes.CONTENT_NOTE_URI, values, NoteColumns.ID
+                                + "=?", new String[] {
+                            String.valueOf(mFocusNoteDataItem.getId())
+                        });
+                    }
+                } else if (!TextUtils.isEmpty(name)) {
+                    ContentValues values = new ContentValues();
+                    values.put(NoteColumns.SNIPPET, name);
+                    values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+                    mContentResolver.insert(Notes.CONTENT_NOTE_URI, values);
+                }
+                dialog.dismiss();
+            }
+        });
+
+        if (TextUtils.isEmpty(etName.getText())) {
+            positive.setEnabled(false);
+        }
+        /**
+         * When the name edit text is null, disable the positive button
+         */
+        etName.addTextChangedListener(new TextWatcher() {
+            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+                // TODO Auto-generated method stub
+
+            }
+
+            public void onTextChanged(CharSequence s, int start, int before, int count) {
+                if (TextUtils.isEmpty(etName.getText())) {
+                    positive.setEnabled(false);
+                } else {
+                    positive.setEnabled(true);
+                }
+            }
+
+            public void afterTextChanged(Editable s) {
+                // TODO Auto-generated method stub
+
+            }
+        });
+    }
+
+    @Override
+    public void onBackPressed() {
+        switch (mState) {
+            case SUB_FOLDER:
+                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+                mState = ListEditState.NOTE_LIST;
+                startAsyncNotesListQuery();
+                mTitleBar.setVisibility(View.GONE);
+                break;
+            case CALL_RECORD_FOLDER:
+                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+                mState = ListEditState.NOTE_LIST;
+                mAddNewNote.setVisibility(View.VISIBLE);
+                mTitleBar.setVisibility(View.GONE);
+                startAsyncNotesListQuery();
+                break;
+            case NOTE_LIST:
+                super.onBackPressed();
+                break;
+            default:
+                break;
+        }
+    }
+
+    private void updateWidget(int appWidgetId, int appWidgetType) {
+        Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
+        if (appWidgetType == Notes.TYPE_WIDGET_2X) {
+            intent.setClass(this, NoteWidgetProvider_2x.class);
+        } else if (appWidgetType == Notes.TYPE_WIDGET_4X) {
+            intent.setClass(this, NoteWidgetProvider_4x.class);
+        } else {
+            Log.e(TAG, "Unspported widget type");
+            return;
+        }
+
+        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, new int[] {
+            appWidgetId
+        });
+
+        sendBroadcast(intent);
+        setResult(RESULT_OK, intent);
+    }
+
+    private final OnCreateContextMenuListener mFolderOnCreateContextMenuListener = new OnCreateContextMenuListener() {
+        public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
+            if (mFocusNoteDataItem != null) {
+                menu.setHeaderTitle(mFocusNoteDataItem.getSnippet());
+                menu.add(0, MENU_FOLDER_VIEW, 0, R.string.menu_folder_view);
+                menu.add(0, MENU_FOLDER_DELETE, 0, R.string.menu_folder_delete);
+                menu.add(0, MENU_FOLDER_CHANGE_NAME, 0, R.string.menu_folder_change_name);
+            }
+        }
+    };
+
+    @Override
+    public void onContextMenuClosed(Menu menu) {
+        if (mNotesListView != null) {
+            mNotesListView.setOnCreateContextMenuListener(null);
+        }
+        super.onContextMenuClosed(menu);
+    }
+
+    @Override
+    public boolean onContextItemSelected(MenuItem item) {
+        if (mFocusNoteDataItem == null) {
+            Log.e(TAG, "The long click data item is null");
+            return false;
+        }
+        switch (item.getItemId()) {
+            case MENU_FOLDER_VIEW:
+                openFolder(mFocusNoteDataItem);
+                break;
+            case MENU_FOLDER_DELETE:
+                AlertDialog.Builder builder = new AlertDialog.Builder(this);
+                builder.setTitle(getString(R.string.alert_title_delete));
+                builder.setIcon(android.R.drawable.ic_dialog_alert);
+                builder.setMessage(getString(R.string.alert_message_delete_folder));
+                builder.setPositiveButton(android.R.string.ok,
+                        new DialogInterface.OnClickListener() {
+                            public void onClick(DialogInterface dialog, int which) {
+                                deleteFolder(mFocusNoteDataItem.getId());
+                            }
+                        });
+                builder.setNegativeButton(android.R.string.cancel, null);
+                builder.show();
+                break;
+            case MENU_FOLDER_CHANGE_NAME:
+                showCreateOrModifyFolderDialog(false);
+                break;
+            default:
+                break;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean onPrepareOptionsMenu(Menu menu) {
+        menu.clear();
+        if (mState == ListEditState.NOTE_LIST) {
+            getMenuInflater().inflate(R.menu.note_list, menu);
+            // set sync or sync_cancel
+            menu.findItem(R.id.menu_sync).setTitle(
+                    GTaskSyncService.isSyncing() ? R.string.menu_sync_cancel : R.string.menu_sync);
+        } else if (mState == ListEditState.SUB_FOLDER) {
+            getMenuInflater().inflate(R.menu.sub_folder, menu);
+        } else if (mState == ListEditState.CALL_RECORD_FOLDER) {
+            getMenuInflater().inflate(R.menu.call_record_folder, menu);
+        } else {
+            Log.e(TAG, "Wrong state:" + mState);
+        }
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case R.id.menu_new_folder: {
+                showCreateOrModifyFolderDialog(true);
+                break;
+            }
+            case R.id.menu_export_text: {
+                exportNoteToText();
+                break;
+            }
+            case R.id.menu_sync: {
+                if (isSyncMode()) {
+                    if (TextUtils.equals(item.getTitle(), getString(R.string.menu_sync))) {
+                        GTaskSyncService.startSync(this);
+                    } else {
+                        GTaskSyncService.cancelSync(this);
+                    }
+                } else {
+                    startPreferenceActivity();
+                }
+                break;
+            }
+            case R.id.menu_setting: {
+                startPreferenceActivity();
+                break;
+            }
+            case R.id.menu_new_note: {
+                createNewNote();
+                break;
+            }
+            case R.id.menu_search:
+                onSearchRequested();
+                break;
+            default:
+                break;
+        }
+        return true;
+    }
+
+    @Override
+    public boolean onSearchRequested() {
+        startSearch(null, false, null /* appData */, false);
+        return true;
+    }
+
+    private void exportNoteToText() {
+        final BackupUtils backup = BackupUtils.getInstance(NotesListActivity.this);
+        new AsyncTask<Void, Void, Integer>() {
+
+            @Override
+            protected Integer doInBackground(Void... unused) {
+                return backup.exportToText();
+            }
+
+            @Override
+            protected void onPostExecute(Integer result) {
+                if (result == BackupUtils.STATE_SD_CARD_UNMOUONTED) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.failed_sdcard_export));
+                    builder.setMessage(NotesListActivity.this
+                            .getString(R.string.error_sdcard_unmounted));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                } else if (result == BackupUtils.STATE_SUCCESS) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.success_sdcard_export));
+                    builder.setMessage(NotesListActivity.this.getString(
+                            R.string.format_exported_file_location, backup
+                                    .getExportedTextFileName(), backup.getExportedTextFileDir()));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                } else if (result == BackupUtils.STATE_SYSTEM_ERROR) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.failed_sdcard_export));
+                    builder.setMessage(NotesListActivity.this
+                            .getString(R.string.error_sdcard_export));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                }
+            }
+
+        }.execute();
+    }
+
+    private boolean isSyncMode() {
+        return NotesPreferenceActivity.getSyncAccountName(this).trim().length() > 0;
+    }
+
+    private void startPreferenceActivity() {
+        Activity from = getParent() != null ? getParent() : this;
+        Intent intent = new Intent(from, NotesPreferenceActivity.class);
+        from.startActivityIfNeeded(intent, -1);
+    }
+
+    private class OnListItemClickListener implements OnItemClickListener {
+
+        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+            if (view instanceof NotesListItem) {
+                NoteItemData item = ((NotesListItem) view).getItemData();
+                if (mNotesListAdapter.isInChoiceMode()) {
+                    if (item.getType() == Notes.TYPE_NOTE) {
+                        position = position - mNotesListView.getHeaderViewsCount();
+                        mModeCallBack.onItemCheckedStateChanged(null, position, id,
+                                !mNotesListAdapter.isSelectedItem(position));
+                    }
+                    return;
+                }
+
+                switch (mState) {
+                    case NOTE_LIST:
+                        if (item.getType() == Notes.TYPE_FOLDER
+                                || item.getType() == Notes.TYPE_SYSTEM) {
+                            openFolder(item);
+                        } else if (item.getType() == Notes.TYPE_NOTE) {
+                            openNode(item);
+                        } else {
+                            Log.e(TAG, "Wrong note type in NOTE_LIST");
+                        }
+                        break;
+                    case SUB_FOLDER:
+                    case CALL_RECORD_FOLDER:
+                        if (item.getType() == Notes.TYPE_NOTE) {
+                            openNode(item);
+                        } else {
+                            Log.e(TAG, "Wrong note type in SUB_FOLDER");
+                        }
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
+
+    }
+
+    private void startQueryDestinationFolders() {
+        String selection = NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>? AND " + NoteColumns.ID + "<>?";
+        selection = (mState == ListEditState.NOTE_LIST) ? selection:
+            "(" + selection + ") OR (" + NoteColumns.ID + "=" + Notes.ID_ROOT_FOLDER + ")";
+
+        mBackgroundQueryHandler.startQuery(FOLDER_LIST_QUERY_TOKEN,
+                null,
+                Notes.CONTENT_NOTE_URI,
+                FoldersListAdapter.PROJECTION,
+                selection,
+                new String[] {
+                        String.valueOf(Notes.TYPE_FOLDER),
+                        String.valueOf(Notes.ID_TRASH_FOLER),
+                        String.valueOf(mCurrentFolderId)
+                },
+                NoteColumns.MODIFIED_DATE + " DESC");
+    }
+
+    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
+        if (view instanceof NotesListItem) {
+            mFocusNoteDataItem = ((NotesListItem) view).getItemData();
+            if (mFocusNoteDataItem.getType() == Notes.TYPE_NOTE && !mNotesListAdapter.isInChoiceMode()) {
+                if (mNotesListView.startActionMode(mModeCallBack) != null) {
+                    mModeCallBack.onItemCheckedStateChanged(null, position, id, true);
+                    mNotesListView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
+                } else {
+                    Log.e(TAG, "startActionMode fails");
+                }
+            } else if (mFocusNoteDataItem.getType() == Notes.TYPE_FOLDER) {
+                mNotesListView.setOnCreateContextMenuListener(mFolderOnCreateContextMenuListener);
+            }
+        }
+        return false;
+    }
+}

NotesProvider.java

@@ -0,0 +1,336 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+
+import android.app.SearchManager;
+import android.content.ContentProvider;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Intent;
+import android.content.UriMatcher;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.net.Uri;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+
+/**
+ * 为存储和获取数据提供接口，可以在不同的应用程序之间共享数据
+ * ContentProvider提供的方法
+ * query：查询
+ * insert：插入
+ * update：更新
+ * delete：删除
+ * getType：得到数据类型
+ */
+public class NotesProvider extends ContentProvider {
+    //UriMatcher用于匹配Uri
+    private static final UriMatcher mMatcher;
+
+    private NotesDatabaseHelper mHelper;
+
+    private static final String TAG = "NotesProvider";
+
+    private static final int URI_NOTE            = 1;
+    private static final int URI_NOTE_ITEM       = 2;
+    private static final int URI_DATA            = 3;
+    private static final int URI_DATA_ITEM       = 4;
+
+    private static final int URI_SEARCH          = 5;
+    private static final int URI_SEARCH_SUGGEST  = 6;
+
+    static {
+        //创建UriMatcher时，调用UriMatcher(UriMatcher.NO_MATCH)表示不匹配任何路径的返回码
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        //把需要匹配Uri路径全部给注册上
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
+    }
+
+    /**
+     * x'0A' represents the '\n' character in sqlite. For title and content in the search result,
+     * we will trim '\n' and white space in order to show more information.
+     */
+    //声明NOTES_SEARCH_PROJECTION
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+//声明NOTES_SNIPPET_SEARCH_QUERY
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+        + " FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    //Context只有在onCreate()中才被初始化
+    //对mHelper进行实例化
+    public boolean onCreate() {
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }
+
+    @Override
+    //查询uri在数据库中对应的位置
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+            String sortOrder) {
+        Cursor c = null;
+        //获取可读数据库
+        SQLiteDatabase db = mHelper.getReadableDatabase();
+        String id = null;
+        //匹配查找uri
+        switch (mMatcher.match(uri)) {
+            //对于不同的匹配值，在数据库中查找相应的条目
+            case URI_NOTE:
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_SEARCH:
+            case URI_SEARCH_SUGGEST:
+                if (sortOrder != null || projection != null) {
+                    //不合法的参数异常
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
+                }
+
+                String searchString = null;
+                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
+                    if (uri.getPathSegments().size() > 1) {
+                        //getPathSegments()方法得到一个String的List，
+                        //在uri.getPathSegments().get(1)为第2个元素
+                        searchString = uri.getPathSegments().get(1);
+                    }
+                } else {
+                    searchString = uri.getQueryParameter("pattern");
+                }
+
+                if (TextUtils.isEmpty(searchString)) {
+                    return null;
+                }
+
+                try {
+                    searchString = String.format("%%%s%%", searchString);
+                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
+                            new String[] { searchString });
+                } catch (IllegalStateException ex) {
+                    Log.e(TAG, "got exception: " + ex.toString());
+                }
+                break;
+            default:
+                //抛出异常
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        return c;
+    }
+
+    @Override
+    //插入一个uri
+    public Uri insert(Uri uri, ContentValues values) {
+        //获得可写的数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        long dataId = 0, noteId = 0, insertedId = 0;
+        switch (mMatcher.match(uri)) {
+            //新增一个条目
+            case URI_NOTE:
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+                //如果存在，查找NOTE_ID
+            case URI_DATA:
+                if (values.containsKey(DataColumns.NOTE_ID)) {
+                    noteId = values.getAsLong(DataColumns.NOTE_ID);
+                } else {
+                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
+                }
+                insertedId = dataId = db.insert(TABLE.DATA, null, values);
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // Notify the note uri
+        //notifyChange获得一个getContentResolver对象并且更新里面的内容
+        if (noteId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
+        }
+
+        // Notify the data uri
+        if (dataId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
+        }
+////返回插入的uri的路径
+        return ContentUris.withAppendedId(uri, insertedId);
+    }
+
+    @Override
+    //删除一个uri
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        //uri代表要操作的数据，Android上可用的每种资源，包括图像、视频片段、音频资源等都可以用uri来表示
+        int count = 0;
+        String id = null;
+        //获得可写的数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean deleteData = false;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);
+                /**
+                 * ID that smaller than 0 is system folder which is not allowed to
+                 * trash
+                 */
+                long noteId = Long.valueOf(id);
+                if (noteId <= 0) {
+                    break;
+                }
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                count = db.delete(TABLE.DATA, selection, selectionArgs);
+                deleteData = true;
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                deleteData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        if (count > 0) {
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+
+    @Override
+    //更新一个uri
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        int count = 0;
+        String id = null;
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean updateData = false;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                increaseNoteVersion(-1, selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);
+                updateData = true;
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                updateData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+
+        if (count > 0) {
+            if (updateData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+//将字符串解析成规定格式
+    private String parseSelection(String selection) {
+        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
+    }
+//增加一个NoteVersion
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+        StringBuilder sql = new StringBuilder(120);
+        sql.append("UPDATE ");
+        sql.append(TABLE.NOTE);
+        sql.append(" SET ");
+        sql.append(NoteColumns.VERSION);
+        sql.append("=" + NoteColumns.VERSION + "+1 ");
+
+        if (id > 0 || !TextUtils.isEmpty(selection)) {
+            sql.append(" WHERE ");
+        }
+        if (id > 0) {
+            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
+        }
+        if (!TextUtils.isEmpty(selection)) {
+            String selectString = id > 0 ? parseSelection(selection) : selection;
+            for (String args : selectionArgs) {
+                selectString = selectString.replaceFirst("\\?", args);
+            }
+            sql.append(selectString);
+        }
+//execSQL()方法可以执行insert、delete、update和CREATE TABLE之类有更改行为的SQL语句
+        mHelper.getWritableDatabase().execSQL(sql.toString());
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}

ResourceParser.java

@@ -0,0 +1,195 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*简介：字面意义是资源分析器，实际上就是获取资源并且在程序中使用，比如颜色图片等
+ * 实现方法：主要利用R.java这个类，其中包括
+ * R.id      组件资源引用
+ * R.drawable  图片资源 （被使用）
+ * R.layout  布局资源
+ * R.menu   菜单资源
+ * R.String  文字资源
+ * R.style    主题资源 （被使用）
+ * 在按顺序设置好相应的id后，就可以编写简单的getXXX函数获取需要的资源
+ * 
+ * 特殊的变量 ：
+ * @BG_DEFAULT_COLOR 默认背景颜色（黄）
+ * BG_DEFAULT_FONT_SIZE 默认文本大小（中）
+ */
+package net.micode.notes.tool;
+
+import android.content.Context;
+import android.preference.PreferenceManager;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+public class ResourceParser {
+
+    public static final int YELLOW           = 0;
+    public static final int BLUE             = 1;
+    public static final int WHITE            = 2;
+    public static final int GREEN            = 3;
+    public static final int RED              = 4;
+
+    public static final int BG_DEFAULT_COLOR = YELLOW;
+
+    public static final int TEXT_SMALL       = 0;
+    public static final int TEXT_MEDIUM      = 1;
+    public static final int TEXT_LARGE       = 2;
+    public static final int TEXT_SUPER       = 3;
+
+    public static final int BG_DEFAULT_FONT_SIZE = TEXT_MEDIUM;
+
+    public static class NoteBgResources {
+        private final static int [] BG_EDIT_RESOURCES = new int [] {
+            R.drawable.edit_yellow,
+            R.drawable.edit_blue,
+            R.drawable.edit_white,
+            R.drawable.edit_green,
+            R.drawable.edit_red
+        };
+
+        private final static int [] BG_EDIT_TITLE_RESOURCES = new int [] {
+            R.drawable.edit_title_yellow,
+            R.drawable.edit_title_blue,
+            R.drawable.edit_title_white,
+            R.drawable.edit_title_green,
+            R.drawable.edit_title_red
+        };
+
+        public static int getNoteBgResource(int id) {
+            return BG_EDIT_RESOURCES[id];
+        }
+
+        public static int getNoteTitleBgResource(int id) {
+            return BG_EDIT_TITLE_RESOURCES[id];
+        }
+    }
+//直接获取默认的背景颜色。
+    public static int getDefaultBgId(Context context) {
+        if (PreferenceManager.getDefaultSharedPreferences(context).getBoolean(
+                NotesPreferenceActivity.PREFERENCE_SET_BG_COLOR_KEY, false)) {
+            return (int) (Math.random() * NoteBgResources.BG_EDIT_RESOURCES.length);
+        } else {
+            return BG_DEFAULT_COLOR;
+        }
+    }
+
+    public static class NoteItemBgResources {
+        private final static int [] BG_FIRST_RESOURCES = new int [] {
+            R.drawable.list_yellow_up,
+            R.drawable.list_blue_up,
+            R.drawable.list_white_up,
+            R.drawable.list_green_up,
+            R.drawable.list_red_up
+        };
+
+        private final static int [] BG_NORMAL_RESOURCES = new int [] {
+            R.drawable.list_yellow_middle,
+            R.drawable.list_blue_middle,
+            R.drawable.list_white_middle,
+            R.drawable.list_green_middle,
+            R.drawable.list_red_middle
+        };
+
+        private final static int [] BG_LAST_RESOURCES = new int [] {
+            R.drawable.list_yellow_down,
+            R.drawable.list_blue_down,
+            R.drawable.list_white_down,
+            R.drawable.list_green_down,
+            R.drawable.list_red_down,
+        };
+
+        private final static int [] BG_SINGLE_RESOURCES = new int [] {
+            R.drawable.list_yellow_single,
+            R.drawable.list_blue_single,
+            R.drawable.list_white_single,
+            R.drawable.list_green_single,
+            R.drawable.list_red_single
+        };
+
+        public static int getNoteBgFirstRes(int id) {
+            return BG_FIRST_RESOURCES[id];
+        }
+
+        public static int getNoteBgLastRes(int id) {
+            return BG_LAST_RESOURCES[id];
+        }
+
+        public static int getNoteBgSingleRes(int id) {
+            return BG_SINGLE_RESOURCES[id];
+        }
+
+        public static int getNoteBgNormalRes(int id) {
+            return BG_NORMAL_RESOURCES[id];
+        }
+
+        public static int getFolderBgRes() {
+            return R.drawable.list_folder;
+        }
+    }
+
+    public static class WidgetBgResources {
+        private final static int [] BG_2X_RESOURCES = new int [] {
+            R.drawable.widget_2x_yellow,
+            R.drawable.widget_2x_blue,
+            R.drawable.widget_2x_white,
+            R.drawable.widget_2x_green,
+            R.drawable.widget_2x_red,
+        };
+
+        public static int getWidget2xBgResource(int id) {
+            return BG_2X_RESOURCES[id];
+        }
+
+        private final static int [] BG_4X_RESOURCES = new int [] {
+            R.drawable.widget_4x_yellow,
+            R.drawable.widget_4x_blue,
+            R.drawable.widget_4x_white,
+            R.drawable.widget_4x_green,
+            R.drawable.widget_4x_red
+        };
+
+        public static int getWidget4xBgResource(int id) {
+            return BG_4X_RESOURCES[id];
+        }
+    }
+
+    public static class TextAppearanceResources {
+        private final static int [] TEXTAPPEARANCE_RESOURCES = new int [] {
+            R.style.TextAppearanceNormal,
+            R.style.TextAppearanceMedium,
+            R.style.TextAppearanceLarge,
+            R.style.TextAppearanceSuper
+        };
+        //这里有一个容错的函数，防止输入的id大于资源总量，若如此，则自动返回默认的设置结果
+        public static int getTexAppearanceResource(int id) {
+            /**
+             * HACKME: Fix bug of store the resource id in shared preference.
+             * The id may larger than the length of resources, in this case,
+             * return the {@link ResourceParser#BG_DEFAULT_FONT_SIZE}
+             */
+            if (id >= TEXTAPPEARANCE_RESOURCES.length) {
+                return BG_DEFAULT_FONT_SIZE;
+            }
+            return TEXTAPPEARANCE_RESOURCES[id];
+        }
+
+        public static int getResourcesSize() {
+            return TEXTAPPEARANCE_RESOURCES.length;
+        }
+    }
+}

SqlData.java

@@ -0,0 +1,204 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**用于支持小米便签最底层的数据库相关操作，和sqlnote的关系上是子集关系，即data是note的子集（节点）
+ * SqlData数据中的数据
+*/
+package net.micode.notes.gtask.data;
+
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+import net.micode.notes.gtask.exception.ActionFailureException;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+public class SqlData {
+    /**实现功能：得到类的简写名称存入字符串TAG中（调用getSimpleName()函数） */
+    private static final String TAG = SqlData.class.getSimpleName();
+
+    private static final int INVALID_ID = -99999;
+/**来自Notes类中定义的DataColumns中的一些常量 */
+
+//集合了interface DataColumns中的所以SF常量
+    public static final String[] PROJECTION_DATA = new String[] {
+            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
+            DataColumns.DATA3
+    };
+/**以下五个变量作为sql表中5列的编号 */
+    public static final int DATA_ID_COLUMN = 0;
+
+    public static final int DATA_MIME_TYPE_COLUMN = 1;
+
+    public static final int DATA_CONTENT_COLUMN = 2;
+
+    public static final int DATA_CONTENT_DATA_1_COLUMN = 3;
+
+    public static final int DATA_CONTENT_DATA_3_COLUMN = 4;
+
+    private ContentResolver mContentResolver;
+//判断是否直接用Content生成，是为true，否则为false
+    private boolean mIsCreate;
+
+    private long mDataId;
+
+    private String mDataMimeType;
+
+    private String mDataContent;
+
+    private long mDataContentData1;
+
+    private String mDataContentData3;
+
+    private ContentValues mDiffDataValues;
+/**实现功能：构造函数，用于初始化数据
+ * mContentResolver用于获取ContentProvider提供的数据
+ * mIsCreate表征当前数据是用哪种方式创建（两种构造函数的参数不同）
+ */
+    public SqlData(Context context) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mDataId = INVALID_ID;//mDataId置初始值-99999
+        mDataMimeType = DataConstants.NOTE;
+        mDataContent = "";
+        mDataContentData1 = 0;
+        mDataContentData3 = "";
+        mDiffDataValues = new ContentValues();
+    }
+/**实现功能：构造函数，初始化数据
+ * mContentResolver用于获取ContentProvider提供的数据
+ * mIsCreate表征当前数据是用哪种方式创建（两种构造函数的参数不同）
+ */
+    public SqlData(Context context, Cursor c) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDiffDataValues = new ContentValues();
+    }
+/**实现功能：从光标处加载数据
+ * 从当前的光标处将五列的数据加载到该类的对象
+ */
+    private void loadFromCursor(Cursor c) {
+        mDataId = c.getLong(DATA_ID_COLUMN);
+        mDataMimeType = c.getString(DATA_MIME_TYPE_COLUMN);
+        mDataContent = c.getString(DATA_CONTENT_COLUMN);
+        mDataContentData1 = c.getLong(DATA_CONTENT_DATA_1_COLUMN);
+        mDataContentData3 = c.getString(DATA_CONTENT_DATA_3_COLUMN);
+    }
+/**实现功能：设置用于共享的数据，并提供异常抛出与处理机制 */
+    public void setContent(JSONObject js) throws JSONException {
+        //如果传入的JSONObject对象中有DataColumns.ID这一项，则设置，否则设为INVALID_ID
+        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
+        if (mIsCreate || mDataId != dataId) {
+            mDiffDataValues.put(DataColumns.ID, dataId);
+        }
+        mDataId = dataId;
+
+        String dataMimeType = js.has(DataColumns.MIME_TYPE) ? js.getString(DataColumns.MIME_TYPE)
+                : DataConstants.NOTE;
+        if (mIsCreate || !mDataMimeType.equals(dataMimeType)) {
+            mDiffDataValues.put(DataColumns.MIME_TYPE, dataMimeType);
+        }
+        mDataMimeType = dataMimeType;
+
+        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
+        if (mIsCreate || !mDataContent.equals(dataContent)) {
+            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
+        }
+        mDataContent = dataContent;
+
+        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
+        if (mIsCreate || mDataContentData1 != dataContentData1) {
+            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
+        }
+        mDataContentData1 = dataContentData1;
+
+        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
+        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
+            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
+        }
+        mDataContentData3 = dataContentData3;
+    }
+/**实现功能：获取共享的数据内容，并提供异常抛出与处理机制 */
+    public JSONObject getContent() throws JSONException {
+        if (mIsCreate) {
+            Log.e(TAG, "it seems that we haven't created this in database yet");
+            return null;
+        }
+        //创建JSONObject对象，并将相关数据放入其中，并返回
+        JSONObject js = new JSONObject();
+        js.put(DataColumns.ID, mDataId);
+        js.put(DataColumns.MIME_TYPE, mDataMimeType);
+        js.put(DataColumns.CONTENT, mDataContent);
+        js.put(DataColumns.DATA1, mDataContentData1);
+        js.put(DataColumns.DATA3, mDataContentData3);
+        return js;
+    }
+/**实现功能：commit函数用于把当前造作所做的修改保存到数据库 */
+    public void commit(long noteId, boolean validateVersion, long version) {
+
+        if (mIsCreate) {
+            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
+                mDiffDataValues.remove(DataColumns.ID);
+            }
+
+            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
+            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
+            try {
+                mDataId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+        } else {
+            if (mDiffDataValues.size() > 0) {
+                int result = 0;
+                if (!validateVersion) {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues, null, null);
+                } else {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues,
+                            " ? in (SELECT " + NoteColumns.ID + " FROM " + TABLE.NOTE
+                                    + " WHERE " + NoteColumns.VERSION + "=?)", new String[] {
+                                    String.valueOf(noteId), String.valueOf(version)
+                            });
+                }
+                if (result == 0) {
+                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
+                }
+            }
+        }
+
+        mDiffDataValues.clear();
+        mIsCreate = false;
+    }
+/**实现功能：获取当前id */
+    public long getId() {
+        return mDataId;
+    }
+}

SqlNote.java

@@ -0,0 +1,512 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**用于支持小米便签最底层的数据库相关操作，和sqldata的关系上是父集关系，即note是data的子父集
+ * 和sqldata相比，sqlnote算是真正意义上的数据
+ */
+package net.micode.notes.gtask.data;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.tool.ResourceParser;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+
+public class SqlNote {
+    /**实现功能：得到类的简写名称，存入字符串TAG中（调用getSimpleName()函数） */
+    private static final String TAG = SqlNote.class.getSimpleName();
+
+    private static final int INVALID_ID = -99999;
+//集合了interface、NoteColumns中所有SF常量
+    public static final String[] PROJECTION_NOTE = new String[] {
+            NoteColumns.ID, NoteColumns.ALERTED_DATE, NoteColumns.BG_COLOR_ID,
+            NoteColumns.CREATED_DATE, NoteColumns.HAS_ATTACHMENT, NoteColumns.MODIFIED_DATE,
+            NoteColumns.NOTES_COUNT, NoteColumns.PARENT_ID, NoteColumns.SNIPPET, NoteColumns.TYPE,
+            NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE, NoteColumns.SYNC_ID,
+            NoteColumns.LOCAL_MODIFIED, NoteColumns.ORIGIN_PARENT_ID, NoteColumns.GTASK_ID,
+            NoteColumns.VERSION
+    };
+//以下设置17列的编号
+    public static final int ID_COLUMN = 0;
+
+    public static final int ALERTED_DATE_COLUMN = 1;
+
+    public static final int BG_COLOR_ID_COLUMN = 2;
+
+    public static final int CREATED_DATE_COLUMN = 3;
+
+    public static final int HAS_ATTACHMENT_COLUMN = 4;
+
+    public static final int MODIFIED_DATE_COLUMN = 5;
+
+    public static final int NOTES_COUNT_COLUMN = 6;
+
+    public static final int PARENT_ID_COLUMN = 7;
+
+    public static final int SNIPPET_COLUMN = 8;
+
+    public static final int TYPE_COLUMN = 9;
+
+    public static final int WIDGET_ID_COLUMN = 10;
+
+    public static final int WIDGET_TYPE_COLUMN = 11;
+
+    public static final int SYNC_ID_COLUMN = 12;
+
+    public static final int LOCAL_MODIFIED_COLUMN = 13;
+
+    public static final int ORIGIN_PARENT_ID_COLUMN = 14;
+
+    public static final int GTASK_ID_COLUMN = 15;
+
+    public static final int VERSION_COLUMN = 16;
+//定义了17个内部的变量，其中12个可以由content中获得，5个需要初始化为0或new
+    private Context mContext;
+
+    private ContentResolver mContentResolver;
+
+    private boolean mIsCreate;
+
+    private long mId;
+
+    private long mAlertDate;
+
+    private int mBgColorId;
+
+    private long mCreatedDate;
+
+    private int mHasAttachment;
+
+    private long mModifiedDate;
+
+    private long mParentId;
+
+    private String mSnippet;
+
+    private int mType;
+
+    private int mWidgetId;
+
+    private int mWidgetType;
+
+    private long mOriginParent;
+
+    private long mVersion;
+
+    private ContentValues mDiffNoteValues;
+
+    private ArrayList<SqlData> mDataList;
+    /**实现功能：构造函数，mIsCreate用于标示构造方式 */
+/**构造函数只有context，对所有的变量进行初始化 */
+    public SqlNote(Context context) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mId = INVALID_ID;
+        mAlertDate = 0;
+        mBgColorId = ResourceParser.getDefaultBgId(context);
+        mCreatedDate = System.currentTimeMillis();//调用系统函数获得创建时间
+        mHasAttachment = 0;
+        mModifiedDate = System.currentTimeMillis();//最后一次修改时间初始化为创建时间
+        mParentId = 0;
+        mSnippet = "";
+        mType = Notes.TYPE_NOTE;
+        mWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+        mOriginParent = 0;
+        mVersion = 0;
+        mDiffNoteValues = new ContentValues();
+        mDataList = new ArrayList<SqlData>();
+    }
+/**实现功能：构造函数，mIsCreate用于标示构造方式 */
+//构造函数有context和一个数据库的cursor，多数变量通过cursor指向的一条记录直接进行初始化
+    public SqlNote(Context context, Cursor c) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+    }
+/**实现功能：构造函数，mIsCreate用于标示构造方式 */
+    public SqlNote(Context context, long id) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(id);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+
+    }
+/**实现功能：通过id从光标处加载数据 */
+    private void loadFromCursor(long id) {
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, PROJECTION_NOTE, "(_id=?)",
+                    new String[] {
+                        String.valueOf(id)
+                    }, null);//通过id获得对应的ContentResolver中的cursor
+            if (c != null) {
+                c.moveToNext();
+                loadFromCursor(c);//然后加载数据进行初始化这样函数
+                //SqlNote（Context context，long id）与SqlNote（Context context，long id）的实现方式基本相同
+            } else {
+                Log.w(TAG, "loadFromCursor: cursor = null");
+            }
+        } finally {
+            if (c != null)
+                c.close();
+        }
+    }
+/**实现功能：通过游标从光标处加载数据 */
+    private void loadFromCursor(Cursor c) {
+        //直接从一条记录中的获得以下变量的初始值
+        mId = c.getLong(ID_COLUMN);
+        mAlertDate = c.getLong(ALERTED_DATE_COLUMN);
+        mBgColorId = c.getInt(BG_COLOR_ID_COLUMN);
+        mCreatedDate = c.getLong(CREATED_DATE_COLUMN);
+        mHasAttachment = c.getInt(HAS_ATTACHMENT_COLUMN);
+        mModifiedDate = c.getLong(MODIFIED_DATE_COLUMN);
+        mParentId = c.getLong(PARENT_ID_COLUMN);
+        mSnippet = c.getString(SNIPPET_COLUMN);
+        mType = c.getInt(TYPE_COLUMN);
+        mWidgetId = c.getInt(WIDGET_ID_COLUMN);
+        mWidgetType = c.getInt(WIDGET_TYPE_COLUMN);
+        mVersion = c.getLong(VERSION_COLUMN);
+    }
+/**实现功能：通过content机制获取共享数据并加载到数据库当前游标处 */
+    private void loadDataContent() {
+        Cursor c = null;
+        mDataList.clear();
+        try {
+            c = mContentResolver.query(Notes.CONTENT_DATA_URI, SqlData.PROJECTION_DATA,
+                    "(note_id=?)", new String[] {
+                        String.valueOf(mId)
+                    }, null);
+            if (c != null) {
+                if (c.getCount() == 0) {
+                    Log.w(TAG, "it seems that the note has not data");
+                    return;
+                }
+                while (c.moveToNext()) {
+                    SqlData data = new SqlData(mContext, c);
+                    mDataList.add(data);
+                }
+            } else {
+                Log.w(TAG, "loadDataContent: cursor = null");
+            }
+        } finally {
+            if (c != null)
+                c.close();
+        }
+    }
+/**实现功能：设置通过content机制用于共享的数据信息 */
+    public boolean setContent(JSONObject js) {
+        try {
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                Log.w(TAG, "cannot set system folder");
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                // for folder we can only update the snnipet and type
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_NOTE) {
+                JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                long id = note.has(NoteColumns.ID) ? note.getLong(NoteColumns.ID) : INVALID_ID;
+                if (mIsCreate || mId != id) {
+                    mDiffNoteValues.put(NoteColumns.ID, id);
+                }
+                mId = id;
+
+                long alertDate = note.has(NoteColumns.ALERTED_DATE) ? note
+                        .getLong(NoteColumns.ALERTED_DATE) : 0;
+                if (mIsCreate || mAlertDate != alertDate) {
+                    mDiffNoteValues.put(NoteColumns.ALERTED_DATE, alertDate);
+                }
+                mAlertDate = alertDate;
+
+                int bgColorId = note.has(NoteColumns.BG_COLOR_ID) ? note
+                        .getInt(NoteColumns.BG_COLOR_ID) : ResourceParser.getDefaultBgId(mContext);
+                if (mIsCreate || mBgColorId != bgColorId) {
+                    mDiffNoteValues.put(NoteColumns.BG_COLOR_ID, bgColorId);
+                }
+                mBgColorId = bgColorId;
+
+                long createDate = note.has(NoteColumns.CREATED_DATE) ? note
+                        .getLong(NoteColumns.CREATED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mCreatedDate != createDate) {
+                    mDiffNoteValues.put(NoteColumns.CREATED_DATE, createDate);
+                }
+                mCreatedDate = createDate;
+
+                int hasAttachment = note.has(NoteColumns.HAS_ATTACHMENT) ? note
+                        .getInt(NoteColumns.HAS_ATTACHMENT) : 0;
+                if (mIsCreate || mHasAttachment != hasAttachment) {
+                    mDiffNoteValues.put(NoteColumns.HAS_ATTACHMENT, hasAttachment);
+                }
+                mHasAttachment = hasAttachment;
+
+                long modifiedDate = note.has(NoteColumns.MODIFIED_DATE) ? note
+                        .getLong(NoteColumns.MODIFIED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mModifiedDate != modifiedDate) {
+                    mDiffNoteValues.put(NoteColumns.MODIFIED_DATE, modifiedDate);
+                }
+                mModifiedDate = modifiedDate;
+
+                long parentId = note.has(NoteColumns.PARENT_ID) ? note
+                        .getLong(NoteColumns.PARENT_ID) : 0;
+                if (mIsCreate || mParentId != parentId) {
+                    mDiffNoteValues.put(NoteColumns.PARENT_ID, parentId);
+                }
+                mParentId = parentId;
+
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+
+                int widgetId = note.has(NoteColumns.WIDGET_ID) ? note.getInt(NoteColumns.WIDGET_ID)
+                        : AppWidgetManager.INVALID_APPWIDGET_ID;
+                if (mIsCreate || mWidgetId != widgetId) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_ID, widgetId);
+                }
+                mWidgetId = widgetId;
+
+                int widgetType = note.has(NoteColumns.WIDGET_TYPE) ? note
+                        .getInt(NoteColumns.WIDGET_TYPE) : Notes.TYPE_WIDGET_INVALIDE;
+                if (mIsCreate || mWidgetType != widgetType) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_TYPE, widgetType);
+                }
+                mWidgetType = widgetType;
+
+                long originParent = note.has(NoteColumns.ORIGIN_PARENT_ID) ? note
+                        .getLong(NoteColumns.ORIGIN_PARENT_ID) : 0;
+                if (mIsCreate || mOriginParent != originParent) {
+                    mDiffNoteValues.put(NoteColumns.ORIGIN_PARENT_ID, originParent);
+                }
+                mOriginParent = originParent;
+
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    SqlData sqlData = null;
+                    if (data.has(DataColumns.ID)) {
+                        long dataId = data.getLong(DataColumns.ID);
+                        for (SqlData temp : mDataList) {
+                            if (dataId == temp.getId()) {
+                                sqlData = temp;
+                            }
+                        }
+                    }
+
+                    if (sqlData == null) {
+                        sqlData = new SqlData(mContext);
+                        mDataList.add(sqlData);
+                    }
+
+                    sqlData.setContent(data);
+                }
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return false;
+        }
+        return true;
+    }
+/**实现功能：获取content机制提供的数据并加载到note中 */
+    public JSONObject getContent() {
+        try {
+            JSONObject js = new JSONObject();
+
+            if (mIsCreate) {
+                Log.e(TAG, "it seems that we haven't created this in database yet");
+                return null;
+            }
+
+            JSONObject note = new JSONObject();
+            if (mType == Notes.TYPE_NOTE) {//类型为note时
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.ALERTED_DATE, mAlertDate);
+                note.put(NoteColumns.BG_COLOR_ID, mBgColorId);
+                note.put(NoteColumns.CREATED_DATE, mCreatedDate);
+                note.put(NoteColumns.HAS_ATTACHMENT, mHasAttachment);
+                note.put(NoteColumns.MODIFIED_DATE, mModifiedDate);
+                note.put(NoteColumns.PARENT_ID, mParentId);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.WIDGET_ID, mWidgetId);
+                note.put(NoteColumns.WIDGET_TYPE, mWidgetType);
+                note.put(NoteColumns.ORIGIN_PARENT_ID, mOriginParent);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+
+                JSONArray dataArray = new JSONArray();
+                for (SqlData sqlData : mDataList) {
+                    JSONObject data = sqlData.getContent();
+                    if (data != null) {
+                        dataArray.put(data);
+                    }
+                }
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+            } else if (mType == Notes.TYPE_FOLDER || mType == Notes.TYPE_SYSTEM) {//类型为文件夹或者是system时
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+            }
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+        return null;
+    }
+/**实现功能：给当前id设置父id */
+    public void setParentId(long id) {
+        mParentId = id;
+        mDiffNoteValues.put(NoteColumns.PARENT_ID, id);
+    }
+/**实现功能：给当前id设置GtaskId */
+    public void setGtaskId(String gid) {
+        mDiffNoteValues.put(NoteColumns.GTASK_ID, gid);
+    }
+/**实现功能：给当前id设置同步id */
+    public void setSyncId(long syncId) {
+        mDiffNoteValues.put(NoteColumns.SYNC_ID, syncId);
+    }
+/**实现功能：初始化本地修改，即撤销所有当前修改 */
+    public void resetLocalModified() {
+        mDiffNoteValues.put(NoteColumns.LOCAL_MODIFIED, 0);
+    }
+/**实现功能：获得当前id */
+    public long getId() {
+        return mId;
+    }
+/**实现功能：获得当前id的父id */
+    public long getParentId() {
+        return mParentId;
+    }
+/**实现功能：获取小片段即用于显示的部分便签内容 */
+    public String getSnippet() {
+        return mSnippet;
+    }
+/**实现功能：判断是否为便签类型 */
+    public boolean isNoteType() {
+        return mType == Notes.TYPE_NOTE;
+    }
+/**实现功能：commit函数用于把当前造作所做的修改保存到数据库 */
+    public void commit(boolean validateVersion) {
+        if (mIsCreate) {
+            if (mId == INVALID_ID && mDiffNoteValues.containsKey(NoteColumns.ID)) {
+                mDiffNoteValues.remove(NoteColumns.ID);
+            }
+
+            Uri uri = mContentResolver.insert(Notes.CONTENT_NOTE_URI, mDiffNoteValues);
+            try {
+                mId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+            if (mId == 0) {
+                throw new IllegalStateException("Create thread id failed");
+            }
+
+            if (mType == Notes.TYPE_NOTE) {
+                for (SqlData sqlData : mDataList) {//直接使用sqldata中的实现
+                    sqlData.commit(mId, false, -1);
+                }
+            }
+        } else {
+            if (mId <= 0 && mId != Notes.ID_ROOT_FOLDER && mId != Notes.ID_CALL_RECORD_FOLDER) {
+                Log.e(TAG, "No such note");
+                throw new IllegalStateException("Try to update note with invalid id");
+            }
+            if (mDiffNoteValues.size() > 0) {
+                mVersion ++;
+                int result = 0;
+                if (!validateVersion) {//构造字符串
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                            + NoteColumns.ID + "=?)", new String[] {
+                        String.valueOf(mId)
+                    });
+                } else {
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                            + NoteColumns.ID + "=?) AND (" + NoteColumns.VERSION + "<=?)",
+                            new String[] {
+                                    String.valueOf(mId), String.valueOf(mVersion)
+                            });
+                }
+                if (result == 0) {
+                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
+                }
+            }
+
+            if (mType == Notes.TYPE_NOTE) {
+                for (SqlData sqlData : mDataList) {
+                    sqlData.commit(mId, validateVersion, mVersion);
+                }
+            }
+        }
+
+        // refresh local info
+        loadFromCursor(mId);
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+
+        mDiffNoteValues.clear();
+        mIsCreate = false;
+    }
+}

Task.java

@@ -0,0 +1,395 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+public class Task extends Node {
+    private static final String TAG = Task.class.getSimpleName();
+
+    private boolean mCompleted;//是否完成
+
+    private String mNotes;//备注信息
+
+    private JSONObject mMetaInfo;//将在实例中存储数据的类型
+
+    private Task mPriorSibling;//对应的优先兄弟Task的指针
+
+    private TaskList mParent;//所在的任务列表的指针
+
+    public Task() {
+        super();
+        mCompleted = false;
+        mNotes = null;
+        mPriorSibling = null;//TaskList中当前Task前面的Task的指针
+        mParent = null;//当前Task所在的TaskList
+        mMetaInfo = null;
+    }
+//获取创建操作的JSON对象
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            // 设置action类型为创建
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            // 设置action的ID
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            // 设置任务在父任务中的索引位置
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mParent.getChildTaskIndex(this));
+
+            // entity_delta
+            // 创建一个实体对象，用于存储任务的创建信息
+            JSONObject entity = new JSONObject();
+            // 设置任务名称
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            // 设置任务创建者ID
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+             // 设置实体类型为任务
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_TASK);
+            if (getNotes() != null) {
+                // 设置任务备注
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+            // 将实体对象添加到JSON对象中
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+            // parent_id
+            // 设置父任务的ID
+            js.put(GTaskStringUtils.GTASK_JSON_PARENT_ID, mParent.getGid());
+
+            // dest_parent_type
+            // 设置目标父类型的值
+            js.put(GTaskStringUtils.GTASK_JSON_DEST_PARENT_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+
+            // list_id
+            // 设置列表ID
+            js.put(GTaskStringUtils.GTASK_JSON_LIST_ID, mParent.getGid());
+
+            // prior_sibling_id
+            // 如果存在前一个兄弟任务，则设置其ID
+            if (mPriorSibling != null) {
+                js.put(GTaskStringUtils.GTASK_JSON_PRIOR_SIBLING_ID, mPriorSibling.getGid());
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-create jsonobject");
+        }
+// 返回包含创建信息的JSON对象
+        return js;
+    }
+
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            // 设置action类型为更新
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            // 设置action的ID
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            // 设置任务的ID
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            // 创建一个实体对象，用于存储任务的更新信息
+            JSONObject entity = new JSONObject();
+            // 设置任务名称
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            if (getNotes() != null) {
+                // 设置任务备注
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+             // 设置任务是否已删除
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            // 将实体对象添加到JSON对象中
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-update jsonobject");
+        }
+// 返回包含更新信息的JSON对象
+        return js;
+    }
+
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }// 设置任务的ID
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }// 设置任务的最后修改时间
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }// 设置任务的名称
+
+                // notes
+                if (js.has(GTaskStringUtils.GTASK_JSON_NOTES)) {
+                    setNotes(js.getString(GTaskStringUtils.GTASK_JSON_NOTES));
+                }// 设置任务的备注
+
+                // deleted
+                if (js.has(GTaskStringUtils.GTASK_JSON_DELETED)) {
+                    setDeleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_DELETED));
+                }// 设置任务是否已删除
+
+                // completed
+                if (js.has(GTaskStringUtils.GTASK_JSON_COMPLETED)) {
+                    setCompleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_COMPLETED));
+                }// 设置任务是否已完成
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get task content from jsonobject");
+            }// 抛出异常，表示从JSON对象获取任务内容失败
+        }
+    }
+
+    public void setContentByLocalJSON(JSONObject js) {
+        // 检查传入的 JSON 对象是否为空，或者是否包含必要的键值
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)
+                || !js.has(GTaskStringUtils.META_HEAD_DATA)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is avaiable");
+        }
+
+        try {
+            // 获取 note 和 dataArray 对象
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+            // 检查 note 的类型是否为 Notes.TYPE_NOTE
+            if (note.getInt(NoteColumns.TYPE) != Notes.TYPE_NOTE) {
+                Log.e(TAG, "invalid type");
+                return;
+            }
+            // 遍历 dataArray，查找 MIME_TYPE 为 DataConstants.NOTE 的数据对象
+            for (int i = 0; i < dataArray.length(); i++) {
+                JSONObject data = dataArray.getJSONObject(i);
+                if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                    // 设置名称为找到的数据对象的 CONTENT 字段的值
+                    setName(data.getString(DataColumns.CONTENT));
+                    break;
+                }
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    public JSONObject getLocalJSONFromContent() {
+        // 获取任务名称
+        String name = getName();
+        try {
+             // 如果元信息为空，说明这是一个从网页创建的新任务
+            if (mMetaInfo == null) {
+                // new task created from web
+                // 如果任务名称为空，记录警告日志并返回null
+                if (name == null) {
+                    Log.w(TAG, "the note seems to be an empty one");
+                    return null;
+                }
+                // 创建一个新的JSON对象用于存储任务信息
+                JSONObject js = new JSONObject();
+                JSONObject note = new JSONObject();
+                JSONArray dataArray = new JSONArray();
+                JSONObject data = new JSONObject();
+                // 将任务名称放入data对象的CONTENT字段中
+                data.put(DataColumns.CONTENT, name);
+                // 将data对象添加到dataArray中
+                dataArray.put(data);
+                // 将dataArray放入js对象的META_HEAD_DATA字段中
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+                // 设置note对象的TYPE字段为Notes.TYPE_NOTE
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                // 将note对象放入js对象的META_HEAD_NOTE字段中
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+                // 返回包含任务信息的js对象
+                return js;
+            } else {
+                // synced task
+                // 如果元信息不为空，说明这是一个已同步的任务
+            // 获取note对象和dataArray对象
+                JSONObject note = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+                JSONArray dataArray = mMetaInfo.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+            // 遍历dataArray，找到类型为DataConstants.NOTE的数据对象
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                        // 将任务名称放入找到的data对象的CONTENT字段中
+                        data.put(DataColumns.CONTENT, getName());
+                        break;
+                    }
+                }
+            // 设置note对象的TYPE字段为Notes.TYPE_NOTE
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                // 返回包含任务信息的mMetaInfo对象
+                return mMetaInfo;
+            }
+        } catch (JSONException e) {
+            // 如果发生异常，记录错误日志并返回null
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+// 设置元信息，将MetaData对象中的notes转换为JSONObject并存储到mMetaInfo中
+    public void setMetaInfo(MetaData metaData) {
+        if (metaData != null && metaData.getNotes() != null) {
+            try {
+                mMetaInfo = new JSONObject(metaData.getNotes());
+            } catch (JSONException e) {
+                Log.w(TAG, e.toString());
+                mMetaInfo = null;
+            }
+        }
+    }
+// 根据Cursor对象获取同步操作类型
+    public int getSyncAction(Cursor c) {
+        try {
+            JSONObject noteInfo = null;
+            if (mMetaInfo != null && mMetaInfo.has(GTaskStringUtils.META_HEAD_NOTE)) {
+                noteInfo = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            }
+
+            if (noteInfo == null) {
+                Log.w(TAG, "it seems that note meta has been deleted");
+                return SYNC_ACTION_UPDATE_REMOTE;
+            }
+
+            if (!noteInfo.has(NoteColumns.ID)) {
+                Log.w(TAG, "remote note id seems to be deleted");
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+
+            // validate the note id now
+            // 验证note id是否匹配
+            if (c.getLong(SqlNote.ID_COLUMN) != noteInfo.getLong(NoteColumns.ID)) {
+                Log.w(TAG, "note id doesn't match");
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+
+            if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+                // there is no local update
+                // 没有本地更新
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // no update both side
+                    // 两边都没有更新
+                    return SYNC_ACTION_NONE;
+                } else {
+                    // apply remote to local
+                    // 应用远程到本地
+                    return SYNC_ACTION_UPDATE_LOCAL;
+                }
+            } else {
+                // validate gtask id
+                // 验证gtask id是否匹配
+                if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                    Log.e(TAG, "gtask id doesn't match");
+                    return SYNC_ACTION_ERROR;
+                }
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // local modification only
+                    // 只有本地修改
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                } else {
+                    return SYNC_ACTION_UPDATE_CONFLICT;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+
+        return SYNC_ACTION_ERROR;
+    }
+// 判断任务是否有价值保存
+    public boolean isWorthSaving() {
+        return mMetaInfo != null || (getName() != null && getName().trim().length() > 0)
+                || (getNotes() != null && getNotes().trim().length() > 0);
+    }
+// 设置任务完成状态
+    public void setCompleted(boolean completed) {
+        this.mCompleted = completed;
+    }
+// 设置任务备注
+    public void setNotes(String notes) {
+        this.mNotes = notes;
+    }
+// 设置前一个兄弟任务
+    public void setPriorSibling(Task priorSibling) {
+        this.mPriorSibling = priorSibling;
+    }
+// 设置任务所属的任务列表
+    public void setParent(TaskList parent) {
+        this.mParent = parent;
+    }
+ // 获取任务完成状态
+    public boolean getCompleted() {
+        return this.mCompleted;
+    }
+// 获取任务备注
+    public String getNotes() {
+        return this.mNotes;
+    }
+ // 获取前一个兄弟任务
+    public Task getPriorSibling() {
+        return this.mPriorSibling;
+    }
+ // 获取任务所属的任务列表
+    public TaskList getParent() {
+        return this.mParent;
+    }
+
+}

TaskList.java

@@ -0,0 +1,347 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+
+public class TaskList extends Node {
+    private static final String TAG = TaskList.class.getSimpleName();//tag标记
+
+    private int mIndex;//当前TaskList的指针
+
+    private ArrayList<Task> mChildren;//类中主要的保存数据的单元，用来实现一个以Task为元素的ArrayList
+
+    public TaskList() {
+        super();
+        mChildren = new ArrayList<Task>();
+        mIndex = 1;
+    }
+/**生成并返回一个包含了一定数据的JSONObject实体 */
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mIndex);
+
+            // entity_delta
+            JSONObject entity = new JSONObject();//entity实体
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-create jsonobject");
+        }
+
+        return js;
+    }
+/**生成并返回一个包含了一定数据的JSONObject实体 */
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-update jsonobject");
+        }
+
+        return js;
+    }
+
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }
+
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get tasklist content from jsonobject");
+            }
+        }
+    }
+
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is avaiable");
+        }
+
+        try {
+            JSONObject folder = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+
+            if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                String name = folder.getString(NoteColumns.SNIPPET);
+                setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + name);
+            } else if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                if (folder.getLong(NoteColumns.ID) == Notes.ID_ROOT_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT);
+                else if (folder.getLong(NoteColumns.ID) == Notes.ID_CALL_RECORD_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                            + GTaskStringUtils.FOLDER_CALL_NOTE);
+                else
+                    Log.e(TAG, "invalid system folder");
+            } else {
+                Log.e(TAG, "error type");
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    public JSONObject getLocalJSONFromContent() {
+        try {
+            JSONObject js = new JSONObject();
+            JSONObject folder = new JSONObject();
+
+            String folderName = getName();
+            if (getName().startsWith(GTaskStringUtils.MIUI_FOLDER_PREFFIX))
+                folderName = folderName.substring(GTaskStringUtils.MIUI_FOLDER_PREFFIX.length(),
+                        folderName.length());
+            folder.put(NoteColumns.SNIPPET, folderName);
+            if (folderName.equals(GTaskStringUtils.FOLDER_DEFAULT)
+                    || folderName.equals(GTaskStringUtils.FOLDER_CALL_NOTE))
+                folder.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+            else
+                folder.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+
+            js.put(GTaskStringUtils.META_HEAD_NOTE, folder);
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public int getSyncAction(Cursor c) {
+        try {
+            if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+                // there is no local update
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // no update both side
+                    return SYNC_ACTION_NONE;
+                } else {
+                    // apply remote to local
+                    return SYNC_ACTION_UPDATE_LOCAL;
+                }
+            } else {
+                // validate gtask id
+                if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                    Log.e(TAG, "gtask id doesn't match");
+                    return SYNC_ACTION_ERROR;
+                }
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // local modification only
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                } else {
+                    // for folder conflicts, just apply local modification
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+
+        return SYNC_ACTION_ERROR;
+    }
+/**获得TaskList的大小，即mChildren的大小 */
+    public int getChildTaskCount() {
+        return mChildren.size();
+    }
+/**返回值为是否成功添加任务
+ * 实现功能：在当前任务表末尾添加新的任务
+ */
+    public boolean addChildTask(Task task) {
+        boolean ret = false;
+        if (task != null && !mChildren.contains(task)) {
+            ret = mChildren.add(task);
+            if (ret) {
+                // need to set prior sibling and parent
+                task.setPriorSibling(mChildren.isEmpty() ? null : mChildren
+                        .get(mChildren.size() - 1));
+                task.setParent(this);
+                //注意：每一次ArrayList的变化都要紧跟相关Task中的PriorSibling的更改，接下来几个函数都有相关操作
+            }
+        }
+        return ret;
+    }
+/**在当前任务表的指定位置添加新的任务 */
+    public boolean addChildTask(Task task, int index) {
+        if (index < 0 || index > mChildren.size()) {
+            Log.e(TAG, "add child task: invalid index");
+            return false;
+        }
+
+        int pos = mChildren.indexOf(task);
+        if (task != null && pos == -1) {
+            mChildren.add(index, task);
+
+            // update the task list
+            Task preTask = null;
+            Task afterTask = null;
+            if (index != 0)
+                preTask = mChildren.get(index - 1);
+            if (index != mChildren.size() - 1)
+                afterTask = mChildren.get(index + 1);
+
+            task.setPriorSibling(preTask);
+            if (afterTask != null)
+                afterTask.setPriorSibling(task);
+        }
+
+        return true;
+    }
+/**返回删除是否成功，删除TaskList中的一个Task */
+    public boolean removeChildTask(Task task) {
+        boolean ret = false;
+        int index = mChildren.indexOf(task);
+        if (index != -1) {
+            ret = mChildren.remove(task);
+
+            if (ret) {
+                // reset prior sibling and parent
+                task.setPriorSibling(null);
+                task.setParent(null);
+
+                // update the task list
+                if (index != mChildren.size()) {
+                    mChildren.get(index).setPriorSibling(
+                            index == 0 ? null : mChildren.get(index - 1));
+                }
+            }
+        }
+        return ret;
+    }
+/**将当前TaskList中含有的某个Task移到index位置 */
+    public boolean moveChildTask(Task task, int index) {
+
+        if (index < 0 || index >= mChildren.size()) {
+            Log.e(TAG, "move child task: invalid index");
+            return false;
+        }
+
+        int pos = mChildren.indexOf(task);
+        if (pos == -1) {
+            Log.e(TAG, "move child task: the task should in the list");
+            return false;
+        }
+
+        if (pos == index)
+            return true;
+        return (removeChildTask(task) && addChildTask(task, index));
+        //利用已实现好的功能完成当下功能
+    }
+/**返回寻找结果，按照gid寻找Task */
+    public Task findChildTaskByGid(String gid) {
+        for (int i = 0; i < mChildren.size(); i++) {
+            Task t = mChildren.get(i);
+            if (t.getGid().equals(gid)) {
+                return t;
+            }
+        }
+        return null;
+    }
+/**返回指定Task的index */
+    public int getChildTaskIndex(Task task) {
+        return mChildren.indexOf(task);
+    }
+/**返回指定index的Task */
+    public Task getChildTaskByIndex(int index) {
+        if (index < 0 || index >= mChildren.size()) {
+            Log.e(TAG, "getTaskByIndex: invalid index");
+            return null;
+        }
+        return mChildren.get(index);
+    }
+/**返回指定gid的Task */
+    public Task getChilTaskByGid(String gid) {
+        for (Task task : mChildren) {//一种常见的ArrayList的遍历方法
+            if (task.getGid().equals(gid))
+                return task;
+        }
+        return null;
+    }
+
+    public ArrayList<Task> getChildTaskList() {
+        return this.mChildren;
+    }
+
+    public void setIndex(int index) {
+        this.mIndex = index;
+    }
+
+    public int getIndex() {
+        return this.mIndex;
+    }
+}

WorkingNote.java

@@ -0,0 +1,388 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.model;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.Notes.TextNote;
+import net.micode.notes.tool.ResourceParser.NoteBgResources;
+
+
+public class WorkingNote {
+    // Note for the working note
+    private Note mNote;
+    // Note Id
+    private long mNoteId;
+    // Note content
+    private String mContent;
+    // Note mode
+    private int mMode;
+
+    private long mAlertDate;
+
+    private long mModifiedDate;
+
+    private int mBgColorId;
+
+    private int mWidgetId;
+
+    private int mWidgetType;
+
+    private long mFolderId;
+
+    private Context mContext;
+
+    private static final String TAG = "WorkingNote";
+
+    private boolean mIsDeleted;
+
+    private NoteSettingChangedListener mNoteSettingStatusListener;
+//声明DATA_PROJECTION字符串数组
+    public static final String[] DATA_PROJECTION = new String[] {
+            DataColumns.ID,
+            DataColumns.CONTENT,
+            DataColumns.MIME_TYPE,
+            DataColumns.DATA1,
+            DataColumns.DATA2,
+            DataColumns.DATA3,
+            DataColumns.DATA4,
+    };
+//声明NOTE_PROJECTION字符串数组
+    public static final String[] NOTE_PROJECTION = new String[] {
+            NoteColumns.PARENT_ID,
+            NoteColumns.ALERTED_DATE,
+            NoteColumns.BG_COLOR_ID,
+            NoteColumns.WIDGET_ID,
+            NoteColumns.WIDGET_TYPE,
+            NoteColumns.MODIFIED_DATE
+    };
+
+    private static final int DATA_ID_COLUMN = 0;
+
+    private static final int DATA_CONTENT_COLUMN = 1;
+
+    private static final int DATA_MIME_TYPE_COLUMN = 2;
+
+    private static final int DATA_MODE_COLUMN = 3;
+
+    private static final int NOTE_PARENT_ID_COLUMN = 0;
+
+    private static final int NOTE_ALERTED_DATE_COLUMN = 1;
+
+    private static final int NOTE_BG_COLOR_ID_COLUMN = 2;
+
+    private static final int NOTE_WIDGET_ID_COLUMN = 3;
+
+    private static final int NOTE_WIDGET_TYPE_COLUMN = 4;
+
+    private static final int NOTE_MODIFIED_DATE_COLUMN = 5;
+
+    // New note construct
+    private WorkingNote(Context context, long folderId) {
+        mContext = context;
+        mAlertDate = 0;
+        mModifiedDate = System.currentTimeMillis();
+        mFolderId = folderId;
+        mNote = new Note();
+        mNoteId = 0;
+        mIsDeleted = false;
+        mMode = 0;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+    }
+//WorkingNote的构造函数
+    // Existing note construct
+    private WorkingNote(Context context, long noteId, long folderId) {
+        mContext = context;
+        mNoteId = noteId;
+        mFolderId = folderId;
+        mIsDeleted = false;
+        mNote = new Note();
+        loadNote();
+    }
+//加载Note
+//通过数据库调用query函数找到第一个条目
+    private void loadNote() {
+        Cursor cursor = mContext.getContentResolver().query(
+                ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, mNoteId), NOTE_PROJECTION, null,
+                null, null);
+//若存在，储存相应信息
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                mFolderId = cursor.getLong(NOTE_PARENT_ID_COLUMN);
+                mBgColorId = cursor.getInt(NOTE_BG_COLOR_ID_COLUMN);
+                mWidgetId = cursor.getInt(NOTE_WIDGET_ID_COLUMN);
+                mWidgetType = cursor.getInt(NOTE_WIDGET_TYPE_COLUMN);
+                mAlertDate = cursor.getLong(NOTE_ALERTED_DATE_COLUMN);
+                mModifiedDate = cursor.getLong(NOTE_MODIFIED_DATE_COLUMN);
+            }
+            cursor.close();
+            //若不存在，报错
+        } else {
+            Log.e(TAG, "No note with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note with id " + mNoteId);
+        }
+        loadNoteData();
+    }
+//加载NoteData
+    private void loadNoteData() {
+        Cursor cursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI, DATA_PROJECTION,
+                DataColumns.NOTE_ID + "=?", new String[] {
+                    String.valueOf(mNoteId)
+                }, null);
+
+        if (cursor != null) {
+            //查到信息不为空
+            if (cursor.moveToFirst()) {//查看第一项是否存在
+                do {
+                    String type = cursor.getString(DATA_MIME_TYPE_COLUMN);
+                    if (DataConstants.NOTE.equals(type)) {
+                        mContent = cursor.getString(DATA_CONTENT_COLUMN);
+                        mMode = cursor.getInt(DATA_MODE_COLUMN);
+                        mNote.setTextDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else if (DataConstants.CALL_NOTE.equals(type)) {
+                        mNote.setCallDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else {
+                        Log.d(TAG, "Wrong note type with type:" + type);
+                    }
+                } while (cursor.moveToNext());//查阅所有项，直到为空
+            }
+            cursor.close();
+        } else {
+            Log.e(TAG, "No data with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note's data with id " + mNoteId);
+        }
+    }
+//创建空的Note
+//传参：context，文件夹id，widget，背景颜色
+    public static WorkingNote createEmptyNote(Context context, long folderId, int widgetId,
+            int widgetType, int defaultBgColorId) {
+        WorkingNote note = new WorkingNote(context, folderId);
+        //设定相关属性
+        note.setBgColorId(defaultBgColorId);
+        note.setWidgetId(widgetId);
+        note.setWidgetType(widgetType);
+        return note;
+    }
+
+    public static WorkingNote load(Context context, long id) {
+        return new WorkingNote(context, id, 0);
+    }
+//保存Note
+    public synchronized boolean saveNote() {
+        if (isWorthSaving()) {//是否值得保存
+            if (!existInDatabase()) {//是否存在数据库中
+                if ((mNoteId = Note.getNewNoteId(mContext, mFolderId)) == 0) {
+                    Log.e(TAG, "Create new note fail with id:" + mNoteId);
+                    return false;
+                }
+            }
+
+            mNote.syncNote(mContext, mNoteId);
+
+            /**
+             * Update widget content if there exist any widget of this note
+             */
+            if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                    && mWidgetType != Notes.TYPE_WIDGET_INVALIDE
+                    && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+//是否在数据库中存在
+    public boolean existInDatabase() {
+        return mNoteId > 0;
+    }
+//是否值得保存
+    private boolean isWorthSaving() {
+        //被删除或（不在数据库中 内容为空）或本地已保存过
+        if (mIsDeleted || (!existInDatabase() && TextUtils.isEmpty(mContent))
+                || (existInDatabase() && !mNote.isLocalModified())) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+//设置mNoteSettingStatusListener
+    public void setOnSettingStatusChangedListener(NoteSettingChangedListener l) {
+        mNoteSettingStatusListener = l;
+    }
+//设置AlertDate
+//若mAlertDate与data不同，则更改mAlertDate并设定NoteValue
+    public void setAlertDate(long date, boolean set) {
+        if (date != mAlertDate) {
+            mAlertDate = date;
+            mNote.setNoteValue(NoteColumns.ALERTED_DATE, String.valueOf(mAlertDate));
+        }
+        if (mNoteSettingStatusListener != null) {
+            mNoteSettingStatusListener.onClockAlertChanged(date, set);
+        }
+    }
+//设定删除标记
+    public void markDeleted(boolean mark) {
+        //设定标记
+        mIsDeleted = mark;
+        if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                && mWidgetType != Notes.TYPE_WIDGET_INVALIDE && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+                //调用mNoteSettingStatusListener的onWidgetChanged方法
+        }
+    }
+//设定背景颜色
+    public void setBgColorId(int id) {
+        if (id != mBgColorId) {//设定条件id != mBgColorId
+            mBgColorId = id;
+            if (mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onBackgroundColorChanged();
+            }
+            mNote.setNoteValue(NoteColumns.BG_COLOR_ID, String.valueOf(id));
+        }
+    }
+//设定检查列表模式
+//参数：mode
+    public void setCheckListMode(int mode) {
+        if (mMode != mode) {//设定条件mMode != mode
+            if (mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onCheckListModeChanged(mMode, mode);
+            }
+            mMode = mode;
+            mNote.setTextData(TextNote.MODE, String.valueOf(mMode));
+        }
+    }
+//设定setWidgetType
+//参数：type
+    public void setWidgetType(int type) {
+        if (type != mWidgetType) {//设定条件type != mWidgetType
+            mWidgetType = type;
+            mNote.setNoteValue(NoteColumns.WIDGET_TYPE, String.valueOf(mWidgetType));
+            //调用Note的setNoteValue方法更改WidgetType
+        }
+    }
+//设定WidgetId
+//参数：id
+    public void setWidgetId(int id) {
+        if (id != mWidgetId) {//设定条件id != mWidgetId
+            mWidgetId = id;
+            mNote.setNoteValue(NoteColumns.WIDGET_ID, String.valueOf(mWidgetId));
+            //调用Note的setNoteValue方法更改WidgetId
+        }
+    }
+//设定WorkingText
+//参数：更改的text
+    public void setWorkingText(String text) {
+        if (!TextUtils.equals(mContent, text)) {//设定条件 mContent，text内容不同
+            mContent = text;
+            mNote.setTextData(DataColumns.CONTENT, mContent);
+            //调用Note的setTextData方法更改WorkingText
+        }
+    }
+//转变mNote的callDate及CallNote信息
+//参数：String phoneNumber，long callDate
+    public void convertToCallNote(String phoneNumber, long callDate) {
+        mNote.setCallData(CallNote.CALL_DATE, String.valueOf(callDate));
+        mNote.setCallData(CallNote.PHONE_NUMBER, phoneNumber);
+        mNote.setNoteValue(NoteColumns.PARENT_ID, String.valueOf(Notes.ID_CALL_RECORD_FOLDER));
+    }
+//判断是否有时钟题型
+    public boolean hasClockAlert() {
+        return (mAlertDate > 0 ? true : false);
+    }
+//获取Content
+    public String getContent() {
+        return mContent;
+    }
+//获取AlertDate
+    public long getAlertDate() {
+        return mAlertDate;
+    }
+//获取ModifiedDate
+    public long getModifiedDate() {
+        return mModifiedDate;
+    }
+//获取背景颜色来源id
+    public int getBgColorResId() {
+        return NoteBgResources.getNoteBgResource(mBgColorId);
+    }
+//获取背景颜色id
+    public int getBgColorId() {
+        return mBgColorId;
+    }
+////获取标题背景颜色id
+    public int getTitleBgResId() {
+        return NoteBgResources.getNoteTitleBgResource(mBgColorId);
+    }
+//获取CheckListMode
+    public int getCheckListMode() {
+        return mMode;
+    }
+//获取便签id
+    public long getNoteId() {
+        return mNoteId;
+    }
+//获取文件夹id
+    public long getFolderId() {
+        return mFolderId;
+    }
+//获取WidgetId
+    public int getWidgetId() {
+        return mWidgetId;
+    }
+//获取WidgetType
+    public int getWidgetType() {
+        return mWidgetType;
+    }
+/**
+ * 创建接口NoteSettingChangedListener，便签更新监视
+ * 为NoteEditActivity提供接口
+ */
+    public interface NoteSettingChangedListener {
+        /**
+         * Called when the background color of current note has just changed
+         */
+        void onBackgroundColorChanged();
+
+        /**
+         * Called when user set clock
+         */
+        void onClockAlertChanged(long date, boolean set);
+
+        /**
+         * Call when user create note from widget
+         */
+        void onWidgetChanged();
+
+        /**
+         * Call when switch between check list mode and normal mode
+         * @param oldMode is previous mode before change
+         * @param newMode is new mode
+         */
+        void onCheckListModeChanged(int oldMode, int newMode);
+    }
+}