diff --git a/src_注释/src/data/Contact.java b/src_注释/src/data/Contact.java
new file mode 100644
index 0000000..50490b7
--- /dev/null
+++ b/src_注释/src/data/Contact.java
@@ -0,0 +1,82 @@
+/*
+ * 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;
+//change
+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;
+        }
+    }
+}
diff --git a/src_注释/src/data/Notes.java b/src_注释/src/data/Notes.java
new file mode 100644
index 0000000..901e7fd
--- /dev/null
+++ b/src_注释/src/data/Notes.java
@@ -0,0 +1,286 @@
+/*
+ * 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.ContentUris;
+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
+     */
+    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 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");
+
+    // public static final Uri my_URI = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI , 10);
+    /**
+     * 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");
+
+    // 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>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id"; //为什么会有parent_id?
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        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>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";//同步
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        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>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        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>
+         */
+        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>
+         */
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        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
+}
diff --git a/src_注释/src/data/NotesDatabaseHelper.java b/src_注释/src/data/NotesDatabaseHelper.java
new file mode 100644
index 0000000..2d11e82
--- /dev/null
+++ b/src_注释/src/data/NotesDatabaseHelper.java
@@ -0,0 +1,371 @@
+/*
+ * 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（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它类使用，
+    //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,但是不知道V2、V3、V4是什么意思
+}
diff --git a/src_注释/src/data/NotesProvider.java b/src_注释/src/data/NotesProvider.java
new file mode 100644
index 0000000..af42d14
--- /dev/null
+++ b/src_注释/src/data/NotesProvider.java
@@ -0,0 +1,338 @@
+/*
+ * 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.
+     */
+    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) {
+        // 插入一个uri
+        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);
+        }
+
+        // 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;
+    }
+
+}
diff --git a/src_注释/src/docx/data/Contact.docx b/src_注释/src/docx/data/Contact.docx
new file mode 100644
index 0000000..50490b7
--- /dev/null
+++ b/src_注释/src/docx/data/Contact.docx
@@ -0,0 +1,82 @@
+/*
+ * 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;
+//change
+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;
+        }
+    }
+}
diff --git a/src_注释/src/docx/data/Notes.docx b/src_注释/src/docx/data/Notes.docx
new file mode 100644
index 0000000..901e7fd
--- /dev/null
+++ b/src_注释/src/docx/data/Notes.docx
@@ -0,0 +1,286 @@
+/*
+ * 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.ContentUris;
+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
+     */
+    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 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");
+
+    // public static final Uri my_URI = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI , 10);
+    /**
+     * 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");
+
+    // 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>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id"; //为什么会有parent_id?
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        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>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";//同步
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        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>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        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>
+         */
+        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>
+         */
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        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
+}
diff --git a/src_注释/src/docx/data/NotesDatabaseHelper.docx b/src_注释/src/docx/data/NotesDatabaseHelper.docx
new file mode 100644
index 0000000..2d11e82
--- /dev/null
+++ b/src_注释/src/docx/data/NotesDatabaseHelper.docx
@@ -0,0 +1,371 @@
+/*
+ * 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（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它类使用，
+    //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,但是不知道V2、V3、V4是什么意思
+}
diff --git a/src_注释/src/docx/data/NotesProvider.docx b/src_注释/src/docx/data/NotesProvider.docx
new file mode 100644
index 0000000..af42d14
--- /dev/null
+++ b/src_注释/src/docx/data/NotesProvider.docx
@@ -0,0 +1,338 @@
+/*
+ * 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.
+     */
+    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) {
+        // 插入一个uri
+        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);
+        }
+
+        // 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;
+    }
+
+}
diff --git a/src_注释/src/docx/gtask_remote/GTaskManager.docx b/src_注释/src/docx/gtask_remote/GTaskManager.docx
new file mode 100644
index 0000000..15cf01d
--- /dev/null
+++ b/src_注释/src/docx/gtask_remote/GTaskManager.docx
@@ -0,0 +1,922 @@
+/*
+ * 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>();                //GoogleID to NodeID??
+        mNidToGid = new HashMap<Long, String>();                //NodeID to GoogleID???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。
+     * 功能：类初始化函数
+     * @author TTS
+     * @return GtaskManger
+     */
+
+    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。
+     * @author TTS
+     * @param activity
+     */
+
+    public synchronized void setActivityContext(Activity activity) {
+        // used for getting authtoken
+        mActivity = activity;
+    }
+
+    /**
+     * 核心函数
+     * 功能：实现了本地同步操作和远端同步操作
+     * @author TTS
+     * @param context-----获取上下文
+     * @param asyncTask-------用于同步的异步操作类
+     * @return int
+     */
+    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;
+    }
+    /**
+     *功能：初始化GtaskList，获取Google上的JSONtasklist转为本地TaskList。
+     *获得的数据存储在mMetaList，mGTaskListHashMap，mGTaskHashMap
+     *@author TTS
+     *@exception NetworkFailureException
+     *@return void
+     */
+
+    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);        //原注释为get action_list------list？？？
+                    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，metadata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);               //为什么加两遍？？？
+
+                    // 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");
+        }
+    }
+
+    /**
+     * 功能：本地内容同步操作
+     * @throws NetworkFailureException
+     * @return 无返回值
+     */
+    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;         //GoogleID?
+        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();
+        }
+
+    }
+    /**
+     * 功能：
+     * @author TTS
+     * @throws NetworkFailureException
+     */
+
+    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();
+    }
+
+    /**
+     * 功能：syncType分类，addLocalNode，addRemoteNode，deleteNode，updateLocalNode，updateRemoteNode
+     * @author TTS
+     * @param syncType
+     * @param node
+     * @param c
+     * @throws NetworkFailureException
+     */
+
+    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");
+        }
+    }
+
+    /**
+     * 功能：本地增加Node
+     * @author TTS
+     * @param node
+     * @throws NetworkFailureException
+     */
+    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);
+    }
+
+    /**
+     * 功能：update本地node
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     * ----Cursor
+     * @throws NetworkFailureException
+     */
+    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);
+    }
+
+    /**
+     * 功能：远程增加Node
+     * 需要updateRemoteMeta
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     * --Cursor
+     * @throws NetworkFailureException
+     */
+    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());
+    }
+
+    /**
+     * 功能：更新远端的Node，包含meta更新(updateRemoteMeta)
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     *  --Cursor
+     * @throws NetworkFailureException
+     */
+    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用途为从本地登陆远端服务器
+
+        // 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由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);
+
+            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);
+    }
+
+    /**
+     * 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。
+     * @author TTS
+     * @param gid
+     * ---GoogleID为String类型
+     * @param sqlNote
+     * ---同步前的数据库操作，故使用类SqlNote
+     * @throws NetworkFailureException
+     */
+    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);
+            }
+        }
+    }
+
+    /**
+     * 功能：刷新本地，给sync的ID对应上最后更改过的对象
+     * @author TTS
+     * @return void
+     * @throws NetworkFailureException
+     */
+    private void refreshLocalSyncId() throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        // get the latest gtask list 获取最近的（最晚的）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--------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;
+            }
+        }
+    }
+
+    /**
+     * 功能：获取同步账号,mAccount.name
+     * @author TTS
+     * @return String
+     */
+    public String getSyncAccount() {
+        return GTaskClient.getInstance().getSyncAccount().name;
+    }
+
+    /**
+     * 功能：取消同步，置mCancelled为true
+     * @author TTS
+     */
+    public void cancelSync() {
+        mCancelled = true;
+    }
+}
diff --git a/src_注释/src/docx/gtask_remote/GTaskSyncService.docx b/src_注释/src/docx/gtask_remote/GTaskSyncService.docx
new file mode 100644
index 0000000..8d5c4a0
--- /dev/null
+++ b/src_注释/src/docx/gtask_remote/GTaskSyncService.docx
@@ -0,0 +1,153 @@
+/*
+ * 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;
+    }
+}
diff --git a/src_注释/src/gtask/remote/GTaskManager.java b/src_注释/src/gtask/remote/GTaskManager.java
new file mode 100644
index 0000000..15cf01d
--- /dev/null
+++ b/src_注释/src/gtask/remote/GTaskManager.java
@@ -0,0 +1,922 @@
+/*
+ * 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>();                //GoogleID to NodeID??
+        mNidToGid = new HashMap<Long, String>();                //NodeID to GoogleID???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。
+     * 功能：类初始化函数
+     * @author TTS
+     * @return GtaskManger
+     */
+
+    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。
+     * @author TTS
+     * @param activity
+     */
+
+    public synchronized void setActivityContext(Activity activity) {
+        // used for getting authtoken
+        mActivity = activity;
+    }
+
+    /**
+     * 核心函数
+     * 功能：实现了本地同步操作和远端同步操作
+     * @author TTS
+     * @param context-----获取上下文
+     * @param asyncTask-------用于同步的异步操作类
+     * @return int
+     */
+    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;
+    }
+    /**
+     *功能：初始化GtaskList，获取Google上的JSONtasklist转为本地TaskList。
+     *获得的数据存储在mMetaList，mGTaskListHashMap，mGTaskHashMap
+     *@author TTS
+     *@exception NetworkFailureException
+     *@return void
+     */
+
+    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);        //原注释为get action_list------list？？？
+                    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，metadata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);               //为什么加两遍？？？
+
+                    // 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");
+        }
+    }
+
+    /**
+     * 功能：本地内容同步操作
+     * @throws NetworkFailureException
+     * @return 无返回值
+     */
+    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;         //GoogleID?
+        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();
+        }
+
+    }
+    /**
+     * 功能：
+     * @author TTS
+     * @throws NetworkFailureException
+     */
+
+    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();
+    }
+
+    /**
+     * 功能：syncType分类，addLocalNode，addRemoteNode，deleteNode，updateLocalNode，updateRemoteNode
+     * @author TTS
+     * @param syncType
+     * @param node
+     * @param c
+     * @throws NetworkFailureException
+     */
+
+    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");
+        }
+    }
+
+    /**
+     * 功能：本地增加Node
+     * @author TTS
+     * @param node
+     * @throws NetworkFailureException
+     */
+    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);
+    }
+
+    /**
+     * 功能：update本地node
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     * ----Cursor
+     * @throws NetworkFailureException
+     */
+    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);
+    }
+
+    /**
+     * 功能：远程增加Node
+     * 需要updateRemoteMeta
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     * --Cursor
+     * @throws NetworkFailureException
+     */
+    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());
+    }
+
+    /**
+     * 功能：更新远端的Node，包含meta更新(updateRemoteMeta)
+     * @author TTS
+     * @param node
+     * ----同步操作的基础数据类型
+     * @param c
+     *  --Cursor
+     * @throws NetworkFailureException
+     */
+    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用途为从本地登陆远端服务器
+
+        // 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由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);
+
+            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);
+    }
+
+    /**
+     * 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。
+     * @author TTS
+     * @param gid
+     * ---GoogleID为String类型
+     * @param sqlNote
+     * ---同步前的数据库操作，故使用类SqlNote
+     * @throws NetworkFailureException
+     */
+    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);
+            }
+        }
+    }
+
+    /**
+     * 功能：刷新本地，给sync的ID对应上最后更改过的对象
+     * @author TTS
+     * @return void
+     * @throws NetworkFailureException
+     */
+    private void refreshLocalSyncId() throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        // get the latest gtask list 获取最近的（最晚的）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--------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;
+            }
+        }
+    }
+
+    /**
+     * 功能：获取同步账号,mAccount.name
+     * @author TTS
+     * @return String
+     */
+    public String getSyncAccount() {
+        return GTaskClient.getInstance().getSyncAccount().name;
+    }
+
+    /**
+     * 功能：取消同步，置mCancelled为true
+     * @author TTS
+     */
+    public void cancelSync() {
+        mCancelled = true;
+    }
+}
diff --git a/src_注释/src/gtask/remote/GTaskSyncService.java b/src_注释/src/gtask/remote/GTaskSyncService.java
new file mode 100644
index 0000000..8d5c4a0
--- /dev/null
+++ b/src_注释/src/gtask/remote/GTaskSyncService.java
@@ -0,0 +1,153 @@
+/*
+ * 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;
+    }
+}
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