Merge pull request '1' (#2) from lzn into dev

src/data/Contact.java

@@ -0,0 +1,77 @@
+/*
+ * 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 {//创建类：联系人
+    private static HashMap<String, String> sContactCache;//存储联系人数据
+    private static final String TAG = "Contact";//自定义标签TAG指向Contact
+
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER//自定义字符串‘caller id selection’
+    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+    + " AND " + Data.RAW_CONTACT_ID + " IN "//定义的callerIDSELEDTION所包含的各项数据
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+
+    public static String getContact(Context context, String phoneNumber) {//获取联系人
+        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) {//如果超出了范围，则在相关日志中进行写Cursor get string error信息
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                cursor.close();
+            }
+            //这里的try和finally和catch都是用来捕捉异常，三个在一起使用时可以保持系统完整性，对异常进行处理。
+        } else {
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}

src/data/Notes.java

@@ -0,0 +1,284 @@
+/*
+ * 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;
+public class Notes {//Notes类，定义一些基本标识符。该类不对标识符进行任何操作，仅仅只是定义，供其他类调用
+    public static final String AUTHORITY = "micode_notes";//定义一个权限名
+    public static final String TAG = "Notes";//设置标签，表示APP的名称是Notes
+    public static final int TYPE_NOTE     = 0;//以下三个常量对NoteColumns.TYPE的值进行设置时会用到
+    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
+     */
+
+    //系统文件标识：根目录0，临时文件夹-1，通话记录-2，垃圾文件夹-3
+    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";//定义了通知日期的ID
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";//定义背景颜色的ID
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";//定义桌面插件的名称
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";//定义桌面插件的类型
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";//定义Note，标识text_note的存放地址
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date";//定义Call_note，标识call_note的存放地址
+
+    public static final int TYPE_WIDGET_INVALIDE      = -1;//小部件标识：无效小部件-1，2*2大小小部件0，4*4大小小部件1
+    public static final int TYPE_WIDGET_2X            = 0;
+    public static final int TYPE_WIDGET_4X            = 1;
+
+    public static class DataConstants {//DataContants类：存放textnotes和callnotes地址
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;//定义变量NOTE，用来识别text_note的存放地址
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;//定义变量CALL_NOTE，用来标志call_note的存放地址
+    }
+
+    /**
+     * Uri to query all notes and folders
+     */
+    //定义查询便签和文件夹的指针。
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * Uri to query data
+     */
+
+    //定义查找数据的指针。
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    public interface NoteColumns {//定义NoteColumns的常量,用于后面创建数据库的表头
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";//定义每一行id
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";//父节点id的字符串
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";//用来保存一些创建信息，比如时间
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";//最近更新的时间等数据
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";//提醒时间等数据
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";//文件夹的名称或便签的内容等数据
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";//note的布局ID
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";//小部件类型
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id";//便签背景颜色的ID
+
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";//设置附件是否存在
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";//通过对相应标签字符串的定义，方便以后准确的引用
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";//文件夹类型还是note类型
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";//最后一次同步的ID
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";//表示是否修改本地的信号
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";//移动到临时文件夹之前的父节点的ID
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";//后台任务的ID
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";//定义版本号
+    }//定义便签属性的常量
+
+    public interface DataColumns {// 定义DataColumns的常量,用于后面创建数据库的表头
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";//定义DataColumns的部分常量
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";//MIME类型能包含视频、图像、文本、音频、应用程序等数据
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";//设置标签的id
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";//创建时间
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";//最新的修改时间
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";//数据包含的内容
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIME_TYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";//文本内容的数据结构
+
+        /**
+         * Generic data column, the meaning is {@link #MIME_TYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";//定义文本内容的类型
+
+        /**
+         * Generic data column, the meaning is {@link #MIME_TYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";//用于文本类型
+
+        /**
+         * Generic data column, the meaning is {@link #MIME_TYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";//定义常量
+
+        /**
+         * Generic data column, the meaning is {@link #MIME_TYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA5 = "data5";//文本内容的数据结构
+    }//主要定义存储便签内容数据
+
+    public static final class TextNote implements DataColumns {//创建文本数据TextNote，继承上面的DataColumns接口
+        /**
+         * Mode to indicate the text in check list mode or not
+         * <P> Type: Integer 1:check list mode 0: normal mode </P>
+         */
+        public static final String MODE = DATA1;//继承了DataColumns中的DATA1
+
+        public static final int MODE_CHECK_LIST = 1;//note中内容的类型
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";//定义内容类型
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";//内容项目的类型
+
+        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 {//通话数据（CallNote）继承了接口类，而后进行了格式适配
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1;//存放通话时间
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3;//放通话号码信息
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";//修改CONTENT_TYPE属性
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";//定义内容项目类型
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");//内容标识符
+    }//电话内容的数据结构
+}

src/data/NotesDatabaseHelper.java

@@ -0,0 +1,362 @@
+/*
+ * 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;
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+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;
+
+
+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
+        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 ''" +
+        ")";//文件夹删除note触发
+
+    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";//在文件夹中移出一个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
+
+    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);
+    }//重新创建上述定义的表格
+
+    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
+
+    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);
+    }//创建表格
+
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }//解决同一时刻只能有一个线程执行
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createNoteTable(db);
+        createDataTable(db);
+    }//实现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
+
+    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

src/data/NotesProvider.java

@@ -0,0 +1,306 @@
+/*
+ * 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;
+//访问、删除、插入、更新、扩展Notes的数据库
+
+public class NotesProvider extends ContentProvider {
+    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;//将以下这些变量放在static模块中，只初始化一次，提高运行速度以及减少空间浪费。将各个Uri与其代号关联在一起
+
+    static {
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        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);
+    }//注册完需要匹配的Uri后，就可以使用sMatcher.match(uri)方法对输入的Uri进行匹配
+
+    /**
+     * 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.
+     */
+    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
+    public boolean onCreate() {
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }//对mHelper进行实例化
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,//查询uri在数据库中对应的位置
+            String sortOrder) {
+        Cursor c = null;
+        SQLiteDatabase db = mHelper.getReadableDatabase();//获取可读数据库
+        String id = null;
+        switch (mMatcher.match(uri)) {//匹配查找uri
+            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://对于不同的匹配值，在数据库中查找相应的条目
+                if (sortOrder != null || projection != null) {
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
+                }//不合法的参数异常
+
+                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
+                        searchString = uri.getPathSegments().get(1);//在uri.getPathSegments().get(1)为第2个元素
+                    }
+                } 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:
+                throw new IllegalArgumentException("Unknown URI " + uri);//抛出异常
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        return c;
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {//插入一个uri
+        SQLiteDatabase db = mHelper.getWritableDatabase();//获得可写的数据库
+        long dataId = 0, noteId = 0, insertedId = 0;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE://新增一个条目
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+            case URI_DATA://如果存在，查找NOTE_ID
+                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ContextResolver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);
+        }
+
+        return ContentUris.withAppendedId(uri, insertedId);//返回插入的uri的路径
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {//删除一个uri
+        int count = 0;
+        String id = null;
+        SQLiteDatabase db = mHelper.getWritableDatabase();//获得可写的数据库
+        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
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {//更新一个uri
+        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;
+    }
+
+    private String parseSelection(String selection) {//将字符串解析成规定格式
+        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
+    }
+
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {//增加一个noteVersion
+        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);
+        }
+
+        mHelper.getWritableDatabase().execSQL(sql.toString());//execSQL()方法可以执行insert、delete、update和CREATE TABLE之类有更改行为的SQL语句
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}

src/gtask/remote/GTaskManager.java

@@ -0,0 +1,802 @@
+/*
+ * 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 {//GTask管理类，封装对GTask进行管理的方法
+    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>();//创建一个节点表
+        mMetaHashMap = new HashMap<String, MetaData>();//创建一个删除本地ID的map
+        mMetaList = null;//创建一个删除本地ID的map
+        mLocalDeleteIdMap = new HashSet<Long>();
+        mGidToNid = new HashMap<String, Long>();//建立一个google id到节点id的映射
+        mNidToGid = new HashMap<Long, String>();
+    }
+
+    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;
+    }
+
+    public synchronized void setActivityContext(Activity activity) {//对类的当前实例进行加锁，防止其他线程同时访问该类的该实例的所有synchronized块
+        // used for getting authtoken
+        mActivity = activity;
+    }
+
+    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;
+    }//若在同步时操作未取消，则返回同步成功
+
+    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(即子元素)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();//原注释为get task list------lists？？？
+
+            // 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()) {//需要保存时，将子任务加入到主任务中
+                            mMetaList.addChildTask(metaData);
+                            if (metaData.getGid() != null) {//操作getGid：取得组识别码函数
+                                mMetaHashMap.put(metaData.getRelatedGid(), metaData);//把元数据放到哈希表中
+                            }
+                        }
+                    }
+                }
+            }
+
+            // create meta list if not existed
+            if (mMetaList == null) {//代码块：若元数据列表不存在则创建一个
+                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++) {//以下循环用于初始化任务列表
+                JSONObject object = jsTaskLists.getJSONObject(i);
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                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);//对任务列表的内容进行设置
+                    mGTaskHashMap.put(gid, tasklist);
+
+                    // load tasks
+                    JSONArray jsTasks = client.getTaskList(gid);//获取任务id号
+                    for (int j = 0; j < jsTasks.length(); j++) {//任务id号
+                        object = (JSONObject) jsTasks.getJSONObject(j);
+                        gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                        Task task = new Task();
+                        task.setContentByRemoteJSON(object);
+                        if (task.isWorthSaving()) {//判断该任务有无价值保存
+                            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");//抛出异常，提交 JSONObject 失败
+        }
+    }
+
+    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) {//对于要删除本地note的情况
+            return;
+        }
+
+        // for local deleted note
+        try {//对于删除本地便签的操作的同步
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,//定位要删除的节点位置
+                    "(type<>? AND parent_id=?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, null);
+            if (c != null) {//若获取到的待删除便签不为空，则进行同步操作
+                while (c.moveToNext()) {//通过while用指针遍历所有结点
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {//节点非空则从哈希表里删除，并进行同步操作
+                        mGTaskHashMap.remove(gid);
+                        doContentSync(Node.SYNC_ACTION_DEL_REMOTE, node, c);
+                    }//在远程删除对应节点
+
+                    mLocalDeleteIdMap.add(c.getLong(SqlNote.ID_COLUMN));//在本地删除记录中添加这一项记录
+                }
+            } else {//若c结点为空，即寻找错误的时候，报错
+                Log.w(TAG, "failed to query trash folder");
+            }
+        } finally {//最后把c关闭并重置
+            if (c != null) {//结束操作之后，将指针指向内容关闭并将指针置空
+                c.close();
+                c = null;
+            }//关闭cursor
+        }
+
+        // sync folder first
+        syncFolder();//对文件夹进行同步
+
+        // for note existing in database
+        try {//对于数据库中已经存在的便签，采取以下操作
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,//使c指针指向待操作的便签位置
+                    "(type=? AND parent_id<>?)", new String[] {//c指针指向待操作的位置
+                            String.valueOf(Notes.TYPE_NOTE), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c != null) {//query语句的用法
+                while (c.moveToNext()) {//指针向后移动
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node != null) {//节点不为空则删除gid，重新建立节点到gid的联系
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, c.getLong(SqlNote.ID_COLUMN));//建立google id到节点id的映射
+                        mNidToGid.put(c.getLong(SqlNote.ID_COLUMN), gid);//通过hashmap建立联系
+                        syncType = node.getSyncAction(c);//更新此时的同步类型
+                    } else {//若为空，先判断sqlnote的trim是否为0，是则确定同步方式为add_remote，否则为del_local
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {//若本地增加了内容，则远程也要增加内容
+                            // local add
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;//远程增加内容
+                        } else {//若本地删除了内容，则远程也要删除内容应的gid
+                            // remote delete
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;//本地删除
+                        }
+                    }
+                    doContentSync(syncType, node, c);//进行同步操作
+                }
+            } else {
+                Log.w(TAG, "failed to query existing note in database");//查询失败时在日志中写回错误信息
+            }
+
+        } finally {//在最后关闭c并重置
+            if (c != null) {//结束操作之后，将指针指向内容关闭并将指针置空
+                c.close();//关闭 cursor 所指文件
+                c = null;//cursor 置空
+            }
+        }
+
+        // go through remaining items
+        Iterator<Map.Entry<String, Node>> iter = mGTaskHashMap.entrySet().iterator();//扫描剩下的项目，逐个进行同步
+        while (iter.hasNext()) {//迭代
+            Map.Entry<String, Node> entry = iter.next();
+            node = entry.getValue();
+            doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);
+        }//在本地增加些节点
+
+        // mCancelled can be set by another thread, so we neet to check one by
+        // one
+        // clear local delete table
+        if (!mCancelled) {//终止标识有可能被其他进程改变，因此需要一个个进行检查
+            if (!DataUtils.batchDeleteNotes(mContentResolver, mLocalDeleteIdMap)) {
+                throw new ActionFailureException("failed to batch-delete local deleted notes");//终止标识有可能被其他线程改变
+            }
+        }
+
+        // refresh local sync id
+        if (!mCancelled) {//更新同步表
+            GTaskClient.getInstance().commitUpdate();
+            refreshLocalSyncId();//更新同步的id
+        }
+
+    }
+
+    private void syncFolder() throws NetworkFailureException {//放在第一种情况之后是因为第一种情况不需要初始化文件夹
+        Cursor c = null;//同步文件夹
+        String gid;
+        Node node;
+        int syncType;
+
+        if (mCancelled) {//判断是否取消该操作
+            return;
+        }
+
+        // for root folder
+        try {//对根文件夹进行更新
+            c = mContentResolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,
+                    Notes.ID_ROOT_FOLDER), SqlNote.PROJECTION_NOTE, null, null, null);//使指针指向根文件夹的位置
+            if (c != null) {
+                c.moveToNext();
+                gid = c.getString(SqlNote.GTASK_ID_COLUMN);//获取指针指向内容对应的gid
+                node = mGTaskHashMap.get(gid);//获取该gid所代表的节点
+                if (node != null) {
+                    mGTaskHashMap.remove(gid);
+                    mGidToNid.put(gid, (long) Notes.ID_ROOT_FOLDER);//将该节点的gid到nid的映射加入映射表
+                    mNidToGid.put((long) Notes.ID_ROOT_FOLDER, gid);
+                    // for system folder, only update remote name if necessary
+                    if (!node.getName().equals(//添加MIUI文件前缀
+                            GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT))
+                        doContentSync(Node.SYNC_ACTION_UPDATE_REMOTE, node, c);
+                } else {
+                    doContentSync(Node.SYNC_ACTION_ADD_REMOTE, node, c);//若非系统文件夹则在远程进行增加节点操作
+                }
+            } else {
+                Log.w(TAG, "failed to query root folder");
+            }
+        } finally {//结束操作之后，最后将指针关闭，并将指针置空。方法与之前相同
+            if (c != null) {//结束操作之后，将指针指向内容关闭并将指针置空
+                c.close();//关闭 cursor 所指文件
+                c = null;//cursor 置空
+            }
+        }
+
+        // for call-note folder
+        try {//对存放电话号码便签的文件夹的同步操作
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE, "(_id=?)",//使指针指向文件夹的位置
+                    new String[] {
+                        String.valueOf(Notes.ID_CALL_RECORD_FOLDER)//添加MIUI文件前缀
+                    }, null);
+            if (c != null) {
+                if (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);//获取指针指向内容对应的gid
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, (long) Notes.ID_CALL_RECORD_FOLDER);//将该节点的gid到nid的映射加入映射表
+                        mNidToGid.put((long) Notes.ID_CALL_RECORD_FOLDER, gid);
+                        // for system folder, only update remote name if
+                        // necessary
+                        if (!node.getName().equals(//若当前访问的文件夹是系统文件夹则只需要更新
+                                GTaskStringUtils.MIUI_FOLDER_PREFFIX//若当前访问的文件夹是系统文件夹则只需更新
+                                        + GTaskStringUtils.FOLDER_CALL_NOTE))
+                            doContentSync(Node.SYNC_ACTION_UPDATE_REMOTE, node, c);
+                    } else {
+                        doContentSync(Node.SYNC_ACTION_ADD_REMOTE, node, c);//若当前访问的文件夹是系统文件夹则只需更新
+                    }
+                }
+            } else {
+                Log.w(TAG, "failed to query call note folder");//警告，询问通讯便签文件夹失败
+            }
+        } finally {
+            if (c != null) {//结束操作之后，将指针指向内容关闭并将指针置空
+                c.close();//关闭 cursor 所指文件
+                c = null;//cursor 置空
+            }
+        }
+
+        // for local existing folders
+        try {//对于本地已存在的文件的操作
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,//使指针指向第一个文件夹的位置
+                    "(type=? AND parent_id<>?)", new String[] {//使指针指向第一个文件夹的位置
+                            String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c != null) {
+                while (c.moveToNext()) {//使指针指向第一个文件夹的位置
+                    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);//获取指针指向内容对应的gid
+                        syncType = node.getSyncAction(c);
+                    } else {//更新同步类型
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {
+                            // local add
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;
+                        } else {//若远程删除了内容，则本地也要删除内容
+                            // remote delete
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;//本地删除
+                        }
+                    }
+                    doContentSync(syncType, node, c);//进行同步操作
+                }
+            } else {
+                Log.w(TAG, "failed to query existing folder");//警告，询问已创建的文件夹失败
+            }
+        } finally {
+            if (c != null) {//结束操作之后，将指针指向内容关闭并将指针置空
+                c.close();//关闭 cursor 所指文件
+                c = null;//cursor 置空
+            }
+        }
+
+        // for remote add folders
+        Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();//远程添加文件需要执行的操作
+        while (iter.hasNext()) {//使用迭代器对远程增添的内容进行遍历
+            Map.Entry<String, TaskList> entry = iter.next();
+            gid = entry.getKey();//获取对应的gid
+            node = entry.getValue();//获取gid对应的节点
+            if (mGTaskHashMap.containsKey(gid)) {//获取gid对应的节点
+                mGTaskHashMap.remove(gid);
+                doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);//进行本地增添操作
+            }
+        }
+
+        if (!mCancelled)
+            GTaskClient.getInstance().commitUpdate();//如果没有取消，在GTsk的客户端进行实例的提交更新
+    }
+
+    private void doContentSync(int syncType, Node node, Cursor c) throws NetworkFailureException {//内容同步，同步同步类型、节点以及数据库指针
+        if (mCancelled) {//如果已经取消同步，直接返回
+            return;
+        }
+
+        MetaData meta;
+        switch (syncType) {//根据同步类型选择操作
+            case Node.SYNC_ACTION_ADD_LOCAL://远程添加
+                addLocalNode(node);//本地添加
+                break;
+            case Node.SYNC_ACTION_ADD_REMOTE://代码块：远程增添
+                addRemoteNode(node, c);//本地删除
+                break;
+            case Node.SYNC_ACTION_DEL_LOCAL://远程删除
+                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://更新本地数据
+                meta = mMetaHashMap.get(node.getGid());//更新本地数据
+                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://更新远程数据
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_UPDATE_CONFLICT://更新时出现冲突
+                // merging both modifications maybe a good idea
+                // right now just use local update simply
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_NONE://空操作
+                break;
+            case Node.SYNC_ACTION_ERROR://操作错误
+            default://同步类型不在规定的类型范围内
+                throw new ActionFailureException("unkown sync action type");//抛出异常，未知的同步行为类型
+        }
+    }
+
+    private void addLocalNode(Node node) throws NetworkFailureException {//增加本地节点的操作，传入参量为待增添的节点
+        if (mCancelled) {//添加本地结点，参数node即为要添加的本地结点
+            return;
+        }
+
+        SqlNote sqlNote;
+        if (node instanceof TaskList) {//若待增添节点为任务列表中的节点，进一步操作
+            if (node.getName().equals(//在根目录中增加节点
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT)) {//指定页面存放的文件夹，加上文件夹默认值判断node节点的名字是否是MIUI系统文件夹的默认文件夹
+                sqlNote = new SqlNote(mContext, Notes.ID_ROOT_FOLDER);
+            } else if (node.getName().equals(//在存放电话号码便签的文件夹中增加节点
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_CALL_NOTE)) {
+                sqlNote = new SqlNote(mContext, Notes.ID_CALL_RECORD_FOLDER);
+            } else {//若没有存放的文件夹，则将其放在根文件夹中
+                sqlNote = new SqlNote(mContext);
+                sqlNote.setContent(node.getLocalJSONFromContent());//从本地任务列表中获取内容
+                sqlNote.setParentId(Notes.ID_ROOT_FOLDER);
+            }
+        } else {//若待增添节点不是任务列表中的节点，进一步操作
+            sqlNote = new SqlNote(mContext);
+            JSONObject js = node.getLocalJSONFromContent();//从待增添节点中获取jsonobject对象
+            try {//异常判断
+                if (js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+                    JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);//获取对应便签的jsonobject对象
+                    if (note.has(NoteColumns.ID)) {//判断便签中是否有条目
+                        long id = note.getLong(NoteColumns.ID);
+                        if (DataUtils.existInNoteDatabase(mContentResolver, id)) {//若便签条目的id已无效，在便签中将其删除
+                            // the id is not available, have to create a new one
+                            note.remove(NoteColumns.ID);
+                        }
+                    }
+                }
+
+                if (js.has(GTaskStringUtils.META_HEAD_DATA)) {//判断便签中的数据条目
+                    JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                    for (int i = 0; i < dataArray.length(); i++) {//依次删除存在的data的ID
+                        JSONObject data = dataArray.getJSONObject(i);//获取对应数据的jsonobject对象
+                        if (data.has(DataColumns.ID)) {//判断数据中是否有条目
+                            long dataId = data.getLong(DataColumns.ID);
+                            if (DataUtils.existInDataDatabase(mContentResolver, dataId)) {//data id存在时删除已建立的对应ID
+                                // the data id is not available, have to create
+                                // a new one
+                                data.remove(DataColumns.ID);
+                            }
+                        }
+                    }
+
+                }
+            } catch (JSONException e) {//出现异常时，打印异常信息
+                Log.w(TAG, e.toString());//获取异常类型和异常详细消息
+                e.printStackTrace();
+            }
+            sqlNote.setContent(js);//将之前的操作获取到的js更新至该节点中
+
+            Long parentId = mGidToNid.get(((Task) node).getParent().getGid());//找到父任务的ID号，并作为sqlNote的父任务的ID，没有父任务则报错
+            if (parentId == null) {//当不能找到该任务上一级的id时报错
+                Log.e(TAG, "cannot find task's parent id locally");//本地无法找到父进程id
+                throw new ActionFailureException("cannot add local node");//报告无法添加本地节点
+            }
+            sqlNote.setParentId(parentId.longValue());
+        }
+
+        // create the local node
+        sqlNote.setGtaskId(node.getGid());//用getGid函数获取node节点的Gid，用于设置本地Gtask的ID
+        sqlNote.commit(false);//更新本地便签
+
+        // update gid-nid mapping
+        mGidToNid.put(node.getGid(), sqlNote.getId());//更新gid与nid的映射表
+        mNidToGid.put(sqlNote.getId(), node.getGid());
+
+        // update meta
+        updateRemoteMeta(node.getGid(), sqlNote);//更新远程的数据
+    }
+
+    private void updateLocalNode(Node node, Cursor c) throws NetworkFailureException {//更新本地节点，两个传入参数，一个是待更新的节点，一个是指向待增加位置的指针
+        if (mCancelled) {//如果正在取消同步，直接返回
+            return;
+        }
+
+        SqlNote sqlNote;//新建一个sql节点并将内容存储进Node中
+        // update the note locally
+        sqlNote = new SqlNote(mContext, c);//新建一个sql节点并将内容存储进Node中
+        sqlNote.setContent(node.getLocalJSONFromContent());//利用待更新节点中的内容对数据库节点进行设置
+
+        Long parentId = (node instanceof Task) ? mGidToNid.get(((Task) node).getParent().getGid())
+                : new Long(Notes.ID_ROOT_FOLDER);// 设置父任务的ID，通过判断node是不是Task的实例
+        if (parentId == null) {//当不能找到该任务上一级的id时报错
+            Log.e(TAG, "cannot find task's parent id locally");//错误，不能在本地找到任务的父 id
+            throw new ActionFailureException("cannot update local node");//抛出异常，不能更新本地节点
+        }
+        sqlNote.setParentId(parentId.longValue());//设置该任务节点上一级的id
+        sqlNote.commit(true);//抛出异常，不能更新本地节点
+
+        // update meta info
+        updateRemoteMeta(node.getGid(), sqlNote);//升级meta
+    }
+
+    private void addRemoteNode(Node node, Cursor c) throws NetworkFailureException {//添加远程节点
+        if (mCancelled) {//如果正在取消同步，直接返回
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);//新建一个sql节点并将内容存储进Node中
+        Node n;
+
+        // update remotely
+        if (sqlNote.isNoteType()) {//若待增添的节点为任务节点，进一步操作
+            Task task = new Task();
+            task.setContentByLocalJSON(sqlNote.getContent());
+
+            String parentGid = mNidToGid.get(sqlNote.getParentId());//找不到parentID时，报错
+            if (parentGid == null) {
+                Log.e(TAG, "cannot find task's parent tasklist");//错误，无法找到任务的父列表
+                throw new ActionFailureException("cannot add remote task");//抛出异常，无法添加云端任务
+            }
+            mGTaskListHashMap.get(parentGid).addChildTask(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;//当文件夹已经存在则跳过处理，若不存在则创建新的文件夹
+            if (sqlNote.getId() == Notes.ID_ROOT_FOLDER)//按照文件夹的形式进行命名
+                folderName += GTaskStringUtils.FOLDER_DEFAULT;
+            else if (sqlNote.getId() == Notes.ID_CALL_RECORD_FOLDER)
+                folderName += GTaskStringUtils.FOLDER_CALL_NOTE;//若为电话号码便签文件夹则按电话号码便签命名
+            else
+                folderName += sqlNote.getSnippet();
+
+            Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();//使用iterator作为map接口，对map进行遍历
+            while (iter.hasNext()) {//iterator迭代器，通过统一的接口迭代所有的map元素
+                Map.Entry<String, TaskList> entry = iter.next();
+                String gid = entry.getKey();
+                TaskList list = entry.getValue();
+
+                if (list.getName().equals(folderName)) {//若寻找到的任务列表已存在，则直接在里面更新
+                    tasklist = list;//找不到可以匹配的任务链
+                    if (mGTaskHashMap.containsKey(gid)) {
+                        mGTaskHashMap.remove(gid);
+                    }
+                    break;
+                }
+            }
+
+            // no match we can add now
+            if (tasklist == null) {//若找不到任务列表，则创建一个新的任务列表
+                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());//更新本地节点
+        sqlNote.commit(false);
+        sqlNote.resetLocalModified();
+        sqlNote.commit(true);
+
+        // gid-id mapping
+        mGidToNid.put(n.getGid(), sqlNote.getId());//更新gid与nid的映射表
+        mNidToGid.put(sqlNote.getId(), n.getGid());
+    }
+
+    private void updateRemoteNode(Node node, Cursor c) throws NetworkFailureException {//更新远程节点
+        if (mCancelled) {//如果正在取消同步，直接返回
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);//在指针指向处创建一个新的节点
+
+        // update remotely
+        node.setContentByLocalJSON(sqlNote.getContent());
+        GTaskClient.getInstance().addUpdateNode(node);//对远程GTask的节点进行更新
+
+        // update meta
+        updateRemoteMeta(node.getGid(), sqlNote);//根据sqlNote和node的Gid更新远程的节点
+
+        // move task if necessary
+        if (sqlNote.isNoteType()) {//判断节点类型是否符合要求
+            Task task = (Task) node;//新建一个task节点
+            TaskList preParentList = task.getParent();//找到当前任务列表的父节点google id和之前父任务链
+
+            String curParentGid = mNidToGid.get(sqlNote.getParentId());//获取上一级任务列表的gid
+            if (curParentGid == null) {//找不到当前任务的上一级任务列表，报错
+                Log.e(TAG, "cannot find task's parent tasklist");//错误，无法找到任务的父列表
+                throw new ActionFailureException("cannot update remote task");//抛出异常，无法添加云端任务
+            }
+            TaskList curParentList = mGTaskListHashMap.get(curParentGid);//通过HashMap找到对应Gid的TaskList
+
+            if (preParentList != curParentList) {//若两个上一级任务列表不一致，进行任务的移动，从之前的任务列表中移动到该列表中
+                preParentList.removeChildTask(task);
+                curParentList.addChildTask(task);
+                GTaskClient.getInstance().moveTask(task, preParentList, curParentList);
+            }
+        }
+
+        // clear local modified flag
+        sqlNote.resetLocalModified();//清除本地的modified flag
+        sqlNote.commit(true);//commit 到本地数据库
+    }
+
+    private void updateRemoteMeta(String gid, SqlNote sqlNote) throws NetworkFailureException {//更新远程元数组的google id和数据库节点
+        if (sqlNote != null && sqlNote.isNoteType()) {//判断节点类型是否符合，类型符合时才进行更新操作
+            MetaData metaData = mMetaHashMap.get(gid);//从google id获取任务列表
+            if (metaData != null) {//若元数据组为空，则创建一个新的元数据组
+                metaData.setMeta(gid, sqlNote.getContent());//通过gid获取元数据
+                GTaskClient.getInstance().addUpdateNode(metaData);
+            } else {//若元数据组不为空，则进行更新
+                metaData = new MetaData();
+                metaData.setMeta(gid, sqlNote.getContent());
+                mMetaList.addChildTask(metaData);
+                mMetaHashMap.put(gid, metaData);
+                GTaskClient.getInstance().createTask(metaData);
+            }
+        }
+    }
+
+    private void refreshLocalSyncId() throws NetworkFailureException {//刷新本地便签id，从远程同步
+        if (mCancelled) {
+            return;
+        }//获取最近的gtask list
+
+        // get the latest gtask list
+        mGTaskHashMap.clear();//否则，初始化hash表
+        mGTaskListHashMap.clear();
+        mMetaHashMap.clear();
+        initGTaskList();
+
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,//使指针指向列表中需要更新的任务
+                    "(type<>? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");//按类型递减顺序返回查询结果
+            if (c != null) {
+                while (c.moveToNext()) {//获取最新的GTask列表
+                    String gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    Node node = mGTaskHashMap.get(gid);
+                    if (node != null) {
+                        mGTaskHashMap.remove(gid);
+                        ContentValues values = new ContentValues();
+                        values.put(NoteColumns.SYNC_ID, node.getLastModified());//在ContentValues中创建键值对。准备通过contentResolver写入数据
+                        mContentResolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,
+                                c.getLong(SqlNote.ID_COLUMN)), values, null, null);//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。
+                    } else {//若发现节点为空则报错
+                        Log.e(TAG, "something is missed");//错误，部分内容丢失
+                        throw new ActionFailureException(
+                                "some local items don't have gid after sync");//抛出异常，部分本地项目在同步后没有 gid
+                    }
+                }
+            } else {//若发现列表为空则报错
+                Log.w(TAG, "failed to query local note to refresh sync id");//警告，询问本地待同步更新的便签 id 失败
+            }
+        } finally {//结束操作之后，将指针指向内容关闭并将指针置空
+            if (c != null) {
+                c.close();//关闭 cursor 所指文件
+                c = null;//cursor 置空
+            }
+        }
+    }
+
+    public String getSyncAccount() {return GTaskClient.getInstance().getSyncAccount().name;}//获取同步账户，通过客户端调用函数获取名字作为信息返回
+
+    public void cancelSync() {
+        mCancelled = true;
+    }//若需要取消同步，则将mCancelled值设置为真
+}

src/gtask/remote/GTaskSyncService.java

@@ -0,0 +1,128 @@
+/*
+ * 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;
+
+public class GTaskSyncService extends Service {//提供GTask的同步服务
+    public final static String ACTION_STRING_NAME = "sync_action_type";//定义一系列静态变量用来表示同步操作的状态
+
+    public final static int ACTION_START_SYNC = 0;
+
+    public final static int ACTION_CANCEL_SYNC = 1;
+
+    public final static int ACTION_INVALID = 2;
+    //用数字0、1、2分别表示开始同步、取消同步、同步无效
+    public final static String GTASK_SERVICE_BROADCAST_NAME = "net.micode.notes.gtask.remote.gtask_sync_service";//服务广播的名称
+
+    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";//表示广播正在同步
+
+    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";//GTask广播服务进程消息
+
+    private static GTaskASyncTask mSyncTask = null;
+
+    private static String mSyncProgress = "";
+
+    private void startSync() {//开始同步的操作
+        if (mSyncTask == null) {//若当前没有同步工作，申请一个task并把指针指向新任务，广播后执行
+            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
+                public void onComplete() {//实现了在GTaskASyncTask类中定义的接口onComplete( )
+                    mSyncTask = null;
+                    sendBroadcast("");//发布广播消息
+                    stopSelf();//完成功能后，将service停掉
+                }
+            });//执行同步任务
+            sendBroadcast("");
+            mSyncTask.execute();//调用同步执行的函数
+        }//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() {//取消同步
+        if (mSyncTask != null) {//同步的任务非空
+            mSyncTask.cancelSync();//取消同步任务
+        }
+    }
+
+    @Override
+    public void onCreate() {
+        mSyncTask = null;
+    }//初始化一个service
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {//告诉系统如何重启服务，如判断是否异常终止后重新启动，在何种情况下异常终止等
+        Bundle bundle = intent.getExtras();//Bundle类可携带数据，用于存放key-value明值对应形式的值
+        if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) {//判断当前的同步状态，根据开始或取消，执行对应操作
+            switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) {//判断当前同步状态，启动或取消
+                case ACTION_START_SYNC:
+                    startSync();//启动同步
+                    break;
+                case ACTION_CANCEL_SYNC:
+                    cancelSync();//取消同步
+                    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() {//内存不足时的处理函数
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+
+    public IBinder onBind(Intent intent) {
+        return null;
+    }//用于绑定操作的函数
+
+    public void sendBroadcast(String msg) {//执行发送广播内容的操作
+        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) {//开始同步
+        GTaskManager.getInstance().setActivityContext(activity);//任务管理器获取活动的内容
+        Intent intent = new Intent(activity, GTaskSyncService.class);//创建新intent
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_START_SYNC);//将之前初始化的各种字符串加入intent
+        activity.startService(intent);//开始同步服务
+    }
+
+    public static void cancelSync(Context context) {//取消同步
+        Intent intent = new Intent(context, GTaskSyncService.class);//显式构建intent，以函数参数context作为第一个参数，以自己GTaskSyncService.class作为目标活动
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_CANCEL_SYNC);
+        context.startService(intent);//使用startService（）执行intent，在本活动基础上打开GTaskSyncService活动
+    }
+
+    public static boolean isSyncing() {
+        return mSyncTask != null;
+    }//判断当前是否处于同步状态
+
+    public static String getProgressString() {
+        return mSyncProgress;
+    }//返回当前同步状态
+}