diff --git a/src/net/micode/notes/data/Contact.java b/src/net/micode/notes/data/Contact.java
new file mode 100644
index 0000000..847f3b5
--- /dev/null
+++ b/src/net/micode/notes/data/Contact.java
@@ -0,0 +1,104 @@
+/*
+ * 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;
+
+
+/**
+ * Contact 类用于从联系人数据库中根据电话号码查找联系人名称。
+ * 使用缓存来优化查找性能，避免重复查询联系人数据库。
+ */
+public class Contact {
+    // 用于缓存电话号码到联系人名称的映射，减少重复查询
+    private static HashMap<String, String> sContactCache;
+
+    // 用于日志输出的 TAG
+    private static final String TAG = "Contact";
+
+    // 查询联系人信息的选择条件，目的是通过电话号码匹配联系人
+    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 = '+')";
+
+    /**
+     * 根据电话号码查找联系人名称。
+     * 使用缓存来提高性能，如果电话号码已经查询过，则直接从缓存中获取联系人名称。
+     *
+     * @param context 应用的上下文对象。
+     * @param phoneNumber 需要查找的电话号码。
+     * @return 如果找到联系人，返回联系人名称，否则返回 null。
+     */
+    public static String getContact(Context context, String phoneNumber) {
+        // 如果缓存为空，则初始化缓存
+        if (sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+
+        // 如果缓存中已经有该电话号码对应的联系人名称，则直接返回缓存中的名称
+        if (sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 使用 PhoneNumberUtils 将电话号码转换为适合匹配的格式
+        String selection = CALLER_ID_SELECTION.replace("+", PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+
+        // 执行查询联系人数据库，获取联系人名称
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,                      // 查询数据的 URI
+                new String[] { Phone.DISPLAY_NAME },    // 查询返回的字段（联系人名称）
+                selection,                              // 查询的条件
+                new String[] { phoneNumber },           // 查询的参数（电话号码）
+                null);                                  // 不进行排序
+
+        // 如果查询结果不为空并且有数据
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                // 获取查询结果中的联系人名称
+                String name = cursor.getString(0);
+
+                // 将结果缓存起来，以便后续查询直接使用缓存
+                sContactCache.put(phoneNumber, name);
+
+                // 返回联系人名称
+                return name;
+            } catch (IndexOutOfBoundsException e) {
+                // 如果出现查询结果格式错误，记录日志并返回 null
+                Log.e(TAG, "Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                // 确保查询完成后关闭 Cursor，避免内存泄漏
+                cursor.close();
+            }
+        } else {
+            // 如果没有匹配的联系人，记录日志并返回 null
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}
+
diff --git a/src/net/micode/notes/data/Notes.java b/src/net/micode/notes/data/Notes.java
new file mode 100644
index 0000000..a55a1df
--- /dev/null
+++ b/src/net/micode/notes/data/Notes.java
@@ -0,0 +1,310 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.net.Uri;
+
+
+/**
+ * Notes 类定义了与笔记和文件夹相关的常量、URI 以及数据库列名常量。
+ * 这些常量用于管理笔记应用中的数据，帮助进行数据查询和处理。
+ */
+public class Notes {
+
+    // Content provider 的 authority，用于在应用内唯一标识 Notes 数据。
+    public static final String AUTHORITY = "micode_notes";
+
+    // 用于日志输出的 TAG
+    public static final String TAG = "Notes";
+
+    // 定义笔记、文件夹、系统文件类型的常量
+    public static final int TYPE_NOTE = 0;
+    public static final int TYPE_FOLDER = 1;
+    public static final int TYPE_SYSTEM = 2;
+
+    /**
+     * 以下常量为系统文件夹的 ID
+     * {@link Notes#ID_ROOT_FOLDER} 是默认的文件夹
+     * {@link Notes#ID_TEMPARAY_FOLDER} 是没有文件夹的笔记
+     * {@link Notes#ID_CALL_RECORD_FOLDER} 是存储通话记录的文件夹
+     */
+    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;
+
+    // Intent 中用到的额外数据键名
+    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";
+
+    // 小部件类型常量
+    public static final int TYPE_WIDGET_INVALIDE = -1;
+    public static final int TYPE_WIDGET_2X = 0;
+    public static final int TYPE_WIDGET_4X = 1;
+
+    // DataConstants 用于指定笔记和通话记录的 MIME 类型
+    public static class DataConstants {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;
+    }
+
+    /**
+     * 用于查询所有笔记和文件夹的 URI
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * 用于查询数据的 URI
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    /**
+     * NoteColumns 接口定义了笔记和文件夹表中列的名称。
+     */
+    public interface NoteColumns {
+
+        /**
+         * 笔记或文件夹的唯一 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * 笔记或文件夹的父 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * 创建日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * 最后修改日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * 提醒日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * 文件夹名称或笔记的文本内容
+         * <P>类型: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * 笔记的小部件 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * 笔记的小部件类型
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * 笔记的背景颜色 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id";
+
+        /**
+         * 标识笔记是否包含附件（如图片、视频等）
+         * <P>类型: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * 文件夹内笔记的数量
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * 文件或笔记的类型：文件夹或笔记
+         * <P>类型: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * 最后的同步 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";
+
+        /**
+         * 标识笔记是否被本地修改过
+         * <P>类型: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * 标识在移动到临时文件夹前的原父 ID
+         * <P>类型: INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * gtask ID，用于与 Google 任务同步
+         * <P>类型: TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * 版本号
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";
+    }
+
+    /**
+     * DataColumns 接口定义了数据表中列的名称。
+     */
+    public interface DataColumns {
+
+        /**
+         * 数据的唯一 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * 数据的 MIME 类型
+         * <P>类型: TEXT </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * 与此数据相关联的笔记 ID
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * 创建日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * 最后修改日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * 数据内容
+         * <P>类型: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+        /**
+         * 通用数据列，具体含义取决于 MIME 类型，通常为整数类型
+         * <P>类型: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * 通用数据列，具体含义取决于 MIME 类型，通常为整数类型
+         * <P>类型: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * 通用数据列，具体含义取决于 MIME 类型，通常为 TEXT 类型
+         * <P>类型: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * 通用数据列，具体含义取决于 MIME 类型，通常为 TEXT 类型
+         * <P>类型: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * 通用数据列，具体含义取决于 MIME 类型，通常为 TEXT 类型
+         * <P>类型: TEXT </P>
+         */
+        public static final String DATA5 = "data5";
+    }
+
+    /**
+     * TextNote 类表示纯文本类型的笔记。
+     */
+    public static final class TextNote implements DataColumns {
+
+        /**
+         * 用于表示笔记是否为待办事项（checklist）模式。
+         * <P>类型: INTEGER, 1: 待办事项模式，0: 普通模式</P>
+         */
+        public static final String MODE = DATA1;
+
+        // 表示文本笔记的 MIME 类型
+        public static final int MODE_CHECK_LIST = 1;
+
+        // 文本笔记的内容类型
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+        // 单个文本笔记的内容项类型
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        // 文本笔记的 URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }
+
+    /**
+     * CallNote 类表示通话记录类型的笔记。
+     */
+    public static final class CallNote implements DataColumns {
+
+        /**
+         * 通话记录的日期
+         * <P>类型: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * 通话记录的电话号码
+         * <P>类型: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3;
+
+        // 通话记录的内容类型
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
+
+        // 单个通话记录的内容项类型
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
+
+        // 通话记录的 URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }
+}
+
diff --git a/src/net/micode/notes/data/NotesDatabaseHelper.java b/src/net/micode/notes/data/NotesDatabaseHelper.java
new file mode 100644
index 0000000..b56745d
--- /dev/null
+++ b/src/net/micode/notes/data/NotesDatabaseHelper.java
@@ -0,0 +1,279 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
+
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+
+
+/**
+ * NotesDatabaseHelper 类用于管理笔记的 SQLite 数据库。
+ * 它继承自 SQLiteOpenHelper，负责数据库的创建、升级和管理。
+ * 包括创建表、触发器以及处理数据库升级。
+ */
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // 数据库名称和版本
+    private static final String DB_NAME = "note.db";
+    private static final int DB_VERSION = 4;
+
+    // 表的名称常量
+    public interface TABLE {
+        public static final String NOTE = "note";   // 笔记表
+        public static final String DATA = "data";   // 数据表
+    }
+
+    // 日志标签
+    private static final String TAG = "NotesDatabaseHelper";
+
+    // NotesDatabaseHelper 的单例实例
+    private static NotesDatabaseHelper mInstance;
+
+    // 创建笔记表的 SQL 语句
+    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" +
+                    ")";
+
+    // 创建数据表的 SQL 语句
+    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 ''" +
+                    ")";
+
+    // 为数据表创建索引
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+            "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+                    TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    // 创建触发器以更新文件夹内笔记的数量（增加和减少）
+    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";
+
+    // 其他触发器省略，具体说明了对笔记和数据的更新、删除时的行为
+
+    /**
+     * NotesDatabaseHelper 的构造函数，接收上下文并初始化数据库。
+     */
+    public NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+    /**
+     * 创建笔记表，并设置相关触发器。
+     */
+    public void createNoteTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_NOTE_TABLE_SQL);  // 创建笔记表
+        reCreateNoteTableTriggers(db);      // 重新创建触发器
+        createSystemFolder(db);             // 创建系统文件夹（如根文件夹、回收站等）
+        Log.d(TAG, "note table has been created");
+    }
+
+    /**
+     * 重新创建笔记表的触发器。
+     */
+    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);
+    }
+
+    /**
+     * 创建系统文件夹，如根文件夹、回收站等。
+     */
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+        // 创建回话记录文件夹
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // 创建根文件夹
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // 创建临时文件夹
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // 创建回收站文件夹
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /**
+     * 创建数据表，并设置相关触发器。
+     */
+    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");
+    }
+
+    /**
+     * 重新创建数据表的触发器。
+     */
+    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);
+    }
+
+    /**
+     * 获取 NotesDatabaseHelper 的单例实例。
+     */
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createNoteTable(db);
+        createDataTable(db);
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // 这次升级包含从v2到v3的升级
+            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");
+        }
+    }
+
+    // 升级数据库到版本2，删除旧表并重新创建
+    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);
+    }
+
+    // 升级数据库到版本3，删除无用的触发器并添加新列
+    private void upgradeToV3(SQLiteDatabase db) {
+        // 删除无用的触发器
+        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");
+
+        // 为笔记表添加 gtask_id 列
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+
+        // 创建回收站文件夹
+        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);
+    }
+
+    // 升级数据库到版本4，添加版本号列
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");
+    }
+}
+
diff --git a/src/net/micode/notes/data/NotesProvider.java b/src/net/micode/notes/data/NotesProvider.java
new file mode 100644
index 0000000..247828a
--- /dev/null
+++ b/src/net/micode/notes/data/NotesProvider.java
@@ -0,0 +1,212 @@
+
+/*
+ * 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;
+
+
+public class NotesProvider extends ContentProvider {
+    // URI Matcher 用于将 URI 映射到相应的操作
+    private static final UriMatcher mMatcher;
+
+    // 数据库帮助类实例
+    private NotesDatabaseHelper mHelper;
+
+    // 日志标签
+    private static final String TAG = "NotesProvider";
+
+    // 定义常量用于 URI 匹配
+    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;
+
+    // 静态代码块，初始化 URI Matcher
+    static {
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE); // 匹配所有笔记
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM); // 匹配单个笔记
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA); // 匹配所有数据
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM); // 匹配单个数据
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH); // 匹配搜索
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST); // 匹配搜索建议
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST); // 匹配搜索建议
+    }
+
+    // 搜索结果的投影（投影是查询中返回的列的集合）
+    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;
+
+    // 搜索的 SQL 查询
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+            + " FROM " + TABLE.NOTE
+            + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+            + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+            + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    public boolean onCreate() {
+        // 初始化 NotesDatabaseHelper 实例
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }
+
+    /**
+     * 查询操作，支持不同 URI 对应不同的查询行为。
+     *
+     * @param uri 查询 URI
+     * @param projection 要查询的列
+     * @param selection 查询条件
+     * @param selectionArgs 查询条件的参数
+     * @param sortOrder 排序方式
+     * @return 查询结果的 Cursor
+     */
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+                        String sortOrder) {
+        Cursor c = null;
+        SQLiteDatabase db = mHelper.getReadableDatabase();
+        String id = null;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_SEARCH:
+            case URI_SEARCH_SUGGEST:
+                // 确保没有传递非法的参数
+                if (sortOrder != null || projection != null) {
+                    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) {
+                        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:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        return c;
+    }
+
+    /**
+     * 插入操作，支持 URI 匹配后将数据插入到相应表中。
+     *
+     * @param uri 插入 URI
+     * @param values 插入的数据
+     * @return 插入后的 URI
+     */
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        long dataId = 0, noteId = 0, insertedId = 0;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+            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);
+        }
+        // 通知 URI 的变化
+        if (noteId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
+        }
+
+        if (dataId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
+        }
+
+        return ContentUris.withAppendedId(uri, insertedId);
+    }
+
+/**
+ * 删除操作，支持 URI 匹配后从相应表中删除数据。
+ *
+ * @param uri 删除的 URI
+ * @param selection 删除条件
+ * @param selectionArgs 删除条件的参数
+ * @return 删除的行数
+ */
+
diff --git a/src/net/micode/notes/gtask/data/MetaData.java b/src/net/micode/notes/gtask/data/MetaData.java
new file mode 100644
index 0000000..a1d07a4
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/MetaData.java
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+
+public class MetaData extends Task {
+    /*
+     * 功能描述：得到类的简写名称存入字符串TAG中
+     * 实现过程：调用getSimpleName ()函数
+     */
+    private final static String TAG = MetaData.class.getSimpleName();
+
+    private String mRelatedGid = null;
+    /*
+     * 功能描述：设置数据，即生成元数据库
+     * 实现过程：调用JSONObject库函数put ()，Task类中的setNotes ()和setName ()函数
+     * 参数注解：
+     */
+    public void setMeta(String gid, JSONObject metaInfo) {
+
+        //对函数块进行注释
+        try {
+            metaInfo.put(GTaskStringUtils.META_HEAD_GTASK_ID, gid);
+            /*
+             * 将这对键值放入metaInfo这个jsonobject对象中
+             */
+        } catch (JSONException e) {
+            Log.e(TAG, "failed to put related gid");
+            /*
+             * 输出错误信息
+             */
+        }
+        setNotes(metaInfo.toString());
+        setName(GTaskStringUtils.META_NOTE_NAME);
+    }
+    /*
+     * 功能描述：获取相关联的Gid
+     */
+    public String getRelatedGid() {
+        return mRelatedGid;
+    }
+    /*
+     * 功能描述：判断当前数据是否为空，若为空则返回真即值得保存
+     * Made By CuiCan
+     */
+    @Override
+    public boolean isWorthSaving() {
+        return getNotes() != null;
+    }
+    /*
+     * 功能描述：使用远程json数据对象设置元数据内容
+     * 实现过程：调用父类Task中的setContentByRemoteJSON ()函数，并
+     * 参数注解：
+     */
+
+    @Override
+    public void setContentByRemoteJSON(JSONObject js) {
+        super.setContentByRemoteJSON(js);
+        if (getNotes() != null) {
+            try {
+                JSONObject metaInfo = new JSONObject(getNotes().trim());
+                mRelatedGid = metaInfo.getString(GTaskStringUtils.META_HEAD_GTASK_ID);
+            } catch (JSONException e) {
+                Log.w(TAG, "failed to get related gid");
+
+                /*
+                 * 输出警告信息
+                 */
+                mRelatedGid = null;
+            }
+        }
+    }
+
+    /*
+     * 功能描述：使用本地json数据对象设置元数据内容，一般不会用到，若用到，则抛出异常
+     * Made By CuiCan
+     */
+    @Override
+    public void setContentByLocalJSON(JSONObject js) {
+        // this function should not be called
+        throw new IllegalAccessError("MetaData:setContentByLocalJSON should not be called");
+        /*
+         * 传递非法参数异常
+         */
+    }
+    /*
+     * 功能描述：从元数据内容中获取本地json对象，一般不会用到，若用到，则抛出异常
+     * Made By CuiCan
+     */
+    @Override
+    public JSONObject getLocalJSONFromContent() {
+        throw new IllegalAccessError("MetaData:getLocalJSONFromContent should not be called");
+        /*
+         * 传递非法参数异常
+         * Made By Cui Can
+         */
+    }
+    /*
+     * 功能描述：获取同步动作状态，一般不会用到，若用到，则抛出异常
+     * Made By CuiCan
+     */
+    @Override
+    public int getSyncAction(Cursor c) {
+        throw new IllegalAccessError("MetaData:getSyncAction should not be called");
+    }
+
+    /*
+     * 传递非法参数异常
+     * Made By Cui Can
+     */
+}
diff --git a/src/net/micode/notes/gtask/data/Node.java b/src/net/micode/notes/gtask/data/Node.java
new file mode 100644
index 0000000..063a1fd
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/Node.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+
+import org.json.JSONObject;
+
+
+public abstract class Node {
+    //定义了各种用于表征同步状态的常量
+    public static final int SYNC_ACTION_NONE = 0;// 本地和云端都无可更新内容（即本地和云端内容一致）
+
+    public static final int SYNC_ACTION_ADD_REMOTE = 1;// 需要在远程云端增加内容
+
+    public static final int SYNC_ACTION_ADD_LOCAL = 2;// 需要在本地增加内容
+
+    public static final int SYNC_ACTION_DEL_REMOTE = 3;// 需要在本地增加内容
+
+    public static final int SYNC_ACTION_DEL_LOCAL = 4;// 需要在远程云端删除内容
+
+    public static final int SYNC_ACTION_UPDATE_REMOTE = 5;// 需要在本地删除内容
+
+    public static final int SYNC_ACTION_UPDATE_LOCAL = 6;// 需要将本地内容更新到远程云端
+
+    public static final int SYNC_ACTION_UPDATE_CONFLICT = 7;// 需要将远程云端内容更新到本地
+
+    public static final int SYNC_ACTION_ERROR = 8;// 同步出现错误
+
+    private String mGid;
+
+    private String mName;
+
+    private long mLastModified;//记录最后一次修改时间
+
+    private boolean mDeleted;//记录最后一次修改时间
+
+    public Node() {
+        mGid = null;
+        mName = "";
+        mLastModified = 0;
+        mDeleted = false;
+    }
+
+    public abstract JSONObject getCreateAction(int actionId);
+
+    public abstract JSONObject getUpdateAction(int actionId);
+
+    public abstract void setContentByRemoteJSON(JSONObject js);
+
+    public abstract void setContentByLocalJSON(JSONObject js);
+
+    public abstract JSONObject getLocalJSONFromContent();
+
+    public abstract int getSyncAction(Cursor c);
+
+    public void setGid(String gid) {
+        this.mGid = gid;
+    }
+
+    public void setName(String name) {
+        this.mName = name;
+    }
+
+    public void setLastModified(long lastModified) {
+        this.mLastModified = lastModified;
+    }
+
+    public void setDeleted(boolean deleted) {
+        this.mDeleted = deleted;
+    }
+
+    public String getGid() {
+        return this.mGid;
+    }
+
+    public String getName() {
+        return this.mName;
+    }
+
+    public long getLastModified() {
+        return this.mLastModified;
+    }
+
+    public boolean getDeleted() {
+        return this.mDeleted;
+    }
+
+}
diff --git a/src/net/micode/notes/gtask/data/SqlData.java b/src/net/micode/notes/gtask/data/SqlData.java
new file mode 100644
index 0000000..d760528
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/SqlData.java
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Description：用于支持小米便签最底层的数据库相关操作，和sqlnote的关系上是子集关系，即data是note的子集（节点）。
+ * SqlData其实就是也就是所谓数据中的数据
+ */
+package net.micode.notes.gtask.data;
+
+
+/*
+ * Description：用于支持小米便签最底层的数据库相关操作，和sqlnote的关系上是子集关系，即data是note的子集（节点）。
+ * SqlData其实就是也就是所谓数据中的数据
+ */
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+import net.micode.notes.gtask.exception.ActionFailureException;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+public class SqlData {
+
+    /*
+     * 功能描述：得到类的简写名称存入字符串TAG中
+     * 实现过程：调用getSimpleName ()函数
+     * Made By CuiCan
+     */
+    private static final String TAG = SqlData.class.getSimpleName();
+
+    private static final int INVALID_ID = -99999;
+
+    /**
+     * 来自Notes类中定义的DataColumn中的一些常量
+     */
+
+    // 集合了interface DataColumns中所有SF常量
+    public static final String[] PROJECTION_DATA = new String[] {
+            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
+            DataColumns.DATA3
+    };
+
+    /**
+     * 以下五个变量作为sql表中5列的编号
+     */
+    public static final int DATA_ID_COLUMN = 0;
+
+    public static final int DATA_MIME_TYPE_COLUMN = 1;
+
+    public static final int DATA_CONTENT_COLUMN = 2;
+
+    public static final int DATA_CONTENT_DATA_1_COLUMN = 3;
+
+    public static final int DATA_CONTENT_DATA_3_COLUMN = 4;
+
+    private ContentResolver mContentResolver;
+    //判断是否直接用Content生成，是为true，否则为false
+    private boolean mIsCreate;
+
+    private long mDataId;
+
+    private String mDataMimeType;
+
+    private String mDataContent;
+
+    private long mDataContentData1;
+
+    private String mDataContentData3;
+
+    private ContentValues mDiffDataValues;
+    /*
+     * 功能描述：构造函数，用于初始化数据
+     * 参数注解：mContentResolver用于获取ContentProvider提供的数据
+     * 参数注解： mIsCreate表征当前数据是用哪种方式创建（两种构造函数的参数不同）
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public SqlData(Context context) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mDataId = INVALID_ID;//mDataId置初始值-99999
+        mDataMimeType = DataConstants.NOTE;
+        mDataContent = "";
+        mDataContentData1 = 0;
+        mDataContentData3 = "";
+        mDiffDataValues = new ContentValues();
+    }
+
+    /*
+     * 功能描述：构造函数，初始化数据
+     * 参数注解：mContentResolver用于获取ContentProvider提供的数据
+     * 参数注解： mIsCreate表征当前数据是用哪种方式创建（两种构造函数的参数不同）
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public SqlData(Context context, Cursor c) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDiffDataValues = new ContentValues();
+    }
+
+    /*
+     * 功能描述：从光标处加载数据
+     * 从当前的光标处将五列的数据加载到该类的对象
+     * Made By CuiCan
+     */
+    private void loadFromCursor(Cursor c) {
+        mDataId = c.getLong(DATA_ID_COLUMN);
+        mDataMimeType = c.getString(DATA_MIME_TYPE_COLUMN);
+        mDataContent = c.getString(DATA_CONTENT_COLUMN);
+        mDataContentData1 = c.getLong(DATA_CONTENT_DATA_1_COLUMN);
+        mDataContentData3 = c.getString(DATA_CONTENT_DATA_3_COLUMN);
+    }
+
+    /*
+     * 功能描述：设置用于共享的数据，并提供异常抛出与处理机制
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public void setContent(JSONObject js) throws JSONException {
+        //如果传入的JSONObject对象中有DataColumns.ID这一项，则设置，否则设为INVALID_ID
+        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
+        if (mIsCreate || mDataId != dataId) {
+            mDiffDataValues.put(DataColumns.ID, dataId);
+        }
+        mDataId = dataId;
+
+        String dataMimeType = js.has(DataColumns.MIME_TYPE) ? js.getString(DataColumns.MIME_TYPE)
+                : DataConstants.NOTE;
+        if (mIsCreate || !mDataMimeType.equals(dataMimeType)) {
+            mDiffDataValues.put(DataColumns.MIME_TYPE, dataMimeType);
+        }
+        mDataMimeType = dataMimeType;
+
+        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
+        if (mIsCreate || !mDataContent.equals(dataContent)) {
+            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
+        }
+        mDataContent = dataContent;
+
+        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
+        if (mIsCreate || mDataContentData1 != dataContentData1) {
+            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
+        }
+        mDataContentData1 = dataContentData1;
+
+        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
+        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
+            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
+        }
+        mDataContentData3 = dataContentData3;
+    }
+    /*
+     * 功能描述：获取共享的数据内容，并提供异常抛出与处理机制
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public JSONObject getContent() throws JSONException {
+        if (mIsCreate) {
+            Log.e(TAG, "it seems that we haven't created this in database yet");
+            return null;
+        }
+
+        //创建JSONObject对象。并将相关数据放入其中，并返回。
+        JSONObject js = new JSONObject();
+        js.put(DataColumns.ID, mDataId);
+        js.put(DataColumns.MIME_TYPE, mDataMimeType);
+        js.put(DataColumns.CONTENT, mDataContent);
+        js.put(DataColumns.DATA1, mDataContentData1);
+        js.put(DataColumns.DATA3, mDataContentData3);
+        return js;
+    }
+
+    /*
+     * 功能描述：commit函数用于把当前造作所做的修改保存到数据库
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public void commit(long noteId, boolean validateVersion, long version) {
+
+        if (mIsCreate) {
+            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
+                mDiffDataValues.remove(DataColumns.ID);
+            }
+
+            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
+            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
+            try {
+                mDataId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+        } else {
+            if (mDiffDataValues.size() > 0) {
+                int result = 0;
+                if (!validateVersion) {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues, null, null);
+                } else {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                                    Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues,
+                            " ? in (SELECT " + NoteColumns.ID + " FROM " + TABLE.NOTE
+                                    + " WHERE " + NoteColumns.VERSION + "=?)", new String[] {
+                                    String.valueOf(noteId), String.valueOf(version)
+                            });
+                }
+                if (result == 0) {
+                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
+                }
+            }
+        }
+
+        mDiffDataValues.clear();
+        mIsCreate = false;
+    }
+
+    /*
+     * 功能描述：获取当前id
+     * 实现过程：
+     * 参数注解：
+     * Made By CuiCan
+     */
+    public long getId() {
+        return mDataId;
+    }
+}
diff --git a/src/net/micode/notes/gtask/data/SqlNote.java b/src/net/micode/notes/gtask/data/SqlNote.java
new file mode 100644
index 0000000..296eaae
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/SqlNote.java
@@ -0,0 +1,526 @@
+/*
+ * 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.
+ */
+
+/*
+ * Description：用于支持小米便签最底层的数据库相关操作，和sqlnote的关系上是子集关系，即data是note的子集（节点）。
+ * SqlData其实就是也就是所谓数据中的数据
+ */
+package net.micode.notes.gtask.data;
+
+
+/*
+ * 功能描述：
+ * 实现过程：
+ * 参数注解：
+ * Made By CuiCan
+ */
+import android.appwidget.AppWidgetManager;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.tool.ResourceParser;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+
+public class SqlNote {
+    /*
+     * 功能描述：得到类的简写名称存入字符串TAG中
+     * 实现过程：调用getSimpleName ()函数
+     * Made By CuiCan
+     */
+    private static final String TAG = SqlNote.class.getSimpleName();
+
+    private static final int INVALID_ID = -99999;
+
+    /**
+     * 来自Notes类中定义的DataColumn中的一些常量
+     */
+
+    // 集合了interface DataColumns中所有SF常量
+    public static final String[] PROJECTION_NOTE = new String[] {
+            NoteColumns.ID, NoteColumns.ALERTED_DATE, NoteColumns.BG_COLOR_ID,
+            NoteColumns.CREATED_DATE, NoteColumns.HAS_ATTACHMENT, NoteColumns.MODIFIED_DATE,
+            NoteColumns.NOTES_COUNT, NoteColumns.PARENT_ID, NoteColumns.SNIPPET, NoteColumns.TYPE,
+            NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE, NoteColumns.SYNC_ID,
+            NoteColumns.LOCAL_MODIFIED, NoteColumns.ORIGIN_PARENT_ID, NoteColumns.GTASK_ID,
+            NoteColumns.VERSION
+    };
+
+    public static final int ID_COLUMN = 0;
+
+    public static final int ALERTED_DATE_COLUMN = 1;
+
+    public static final int BG_COLOR_ID_COLUMN = 2;
+
+    public static final int CREATED_DATE_COLUMN = 3;
+
+    public static final int HAS_ATTACHMENT_COLUMN = 4;
+
+    public static final int MODIFIED_DATE_COLUMN = 5;
+
+    public static final int NOTES_COUNT_COLUMN = 6;
+
+    public static final int PARENT_ID_COLUMN = 7;
+
+    public static final int SNIPPET_COLUMN = 8;
+
+    public static final int TYPE_COLUMN = 9;
+
+    public static final int WIDGET_ID_COLUMN = 10;
+
+    public static final int WIDGET_TYPE_COLUMN = 11;
+
+    public static final int SYNC_ID_COLUMN = 12;
+
+    public static final int LOCAL_MODIFIED_COLUMN = 13;
+
+    public static final int ORIGIN_PARENT_ID_COLUMN = 14;
+
+    public static final int GTASK_ID_COLUMN = 15;
+
+    public static final int VERSION_COLUMN = 16;
+
+    private Context mContext;
+    //判断是否直接用Content生成，是为true，否则为false
+    private ContentResolver mContentResolver;
+
+    private boolean mIsCreate;
+
+    private long mId;
+
+    private long mAlertDate;
+
+    private int mBgColorId;
+
+    private long mCreatedDate;
+
+    private int mHasAttachment;
+
+    private long mModifiedDate;
+
+    private long mParentId;
+
+    private String mSnippet;
+
+    private int mType;
+
+    private int mWidgetId;
+
+    private int mWidgetType;
+
+    private long mOriginParent;
+
+    private long mVersion;
+
+    private ContentValues mDiffNoteValues;
+
+    private ArrayList<SqlData> mDataList;
+
+    public SqlNote(Context context) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mId = INVALID_ID;//mDataId置初始值-99999
+        mAlertDate = 0;
+        mBgColorId = ResourceParser.getDefaultBgId(context);
+        mCreatedDate = System.currentTimeMillis();
+        mHasAttachment = 0;
+        mModifiedDate = System.currentTimeMillis();
+        mParentId = 0;
+        mSnippet = "";
+        mType = Notes.TYPE_NOTE;
+        mWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+        mOriginParent = 0;
+        mVersion = 0;
+        mDiffNoteValues = new ContentValues();
+        mDataList = new ArrayList<SqlData>();
+    }
+
+    public SqlNote(Context context, Cursor c) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+    }
+
+    public SqlNote(Context context, long id) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(id);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+
+    }
+
+    private void loadFromCursor(long id) {
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, PROJECTION_NOTE, "(_id=?)",
+                    new String[] {
+                            String.valueOf(id)
+                    }, null);
+            if (c != null) {
+                c.moveToNext();
+                loadFromCursor(c);
+            } else {
+                Log.w(TAG, "loadFromCursor: cursor = null");
+            }
+        } finally {
+            if (c != null)
+                c.close();
+        }
+    }
+
+    private void loadFromCursor(Cursor c) {
+        mId = c.getLong(ID_COLUMN);
+        mAlertDate = c.getLong(ALERTED_DATE_COLUMN);
+        mBgColorId = c.getInt(BG_COLOR_ID_COLUMN);
+        mCreatedDate = c.getLong(CREATED_DATE_COLUMN);
+        mHasAttachment = c.getInt(HAS_ATTACHMENT_COLUMN);
+        mModifiedDate = c.getLong(MODIFIED_DATE_COLUMN);
+        mParentId = c.getLong(PARENT_ID_COLUMN);
+        mSnippet = c.getString(SNIPPET_COLUMN);
+        mType = c.getInt(TYPE_COLUMN);
+        mWidgetId = c.getInt(WIDGET_ID_COLUMN);
+        mWidgetType = c.getInt(WIDGET_TYPE_COLUMN);
+        mVersion = c.getLong(VERSION_COLUMN);
+    }
+
+    private void loadDataContent() {
+        Cursor c = null;
+        mDataList.clear();
+        try {
+            c = mContentResolver.query(Notes.CONTENT_DATA_URI, SqlData.PROJECTION_DATA,
+                    "(note_id=?)", new String[] {
+                            String.valueOf(mId)
+                    }, null);
+            if (c != null) {
+                if (c.getCount() == 0) {
+                    Log.w(TAG, "it seems that the note has not data");
+                    return;
+                }
+                while (c.moveToNext()) {
+                    SqlData data = new SqlData(mContext, c);
+                    mDataList.add(data);
+                }
+            } else {
+                Log.w(TAG, "loadDataContent: cursor = null");
+            }
+        } finally {
+            if (c != null)
+                c.close();
+        }
+    }
+
+    public boolean setContent(JSONObject js) {
+        try {
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                Log.w(TAG, "cannot set system folder");
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                // for folder we can only update the snnipet and type
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_NOTE) {
+                JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                long id = note.has(NoteColumns.ID) ? note.getLong(NoteColumns.ID) : INVALID_ID;
+                if (mIsCreate || mId != id) {
+                    mDiffNoteValues.put(NoteColumns.ID, id);
+                }
+                mId = id;
+
+                long alertDate = note.has(NoteColumns.ALERTED_DATE) ? note
+                        .getLong(NoteColumns.ALERTED_DATE) : 0;
+                if (mIsCreate || mAlertDate != alertDate) {
+                    mDiffNoteValues.put(NoteColumns.ALERTED_DATE, alertDate);
+                }
+                mAlertDate = alertDate;
+
+                int bgColorId = note.has(NoteColumns.BG_COLOR_ID) ? note
+                        .getInt(NoteColumns.BG_COLOR_ID) : ResourceParser.getDefaultBgId(mContext);
+                if (mIsCreate || mBgColorId != bgColorId) {
+                    mDiffNoteValues.put(NoteColumns.BG_COLOR_ID, bgColorId);
+                }
+                mBgColorId = bgColorId;
+
+                long createDate = note.has(NoteColumns.CREATED_DATE) ? note
+                        .getLong(NoteColumns.CREATED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mCreatedDate != createDate) {
+                    mDiffNoteValues.put(NoteColumns.CREATED_DATE, createDate);
+                }
+                mCreatedDate = createDate;
+
+                int hasAttachment = note.has(NoteColumns.HAS_ATTACHMENT) ? note
+                        .getInt(NoteColumns.HAS_ATTACHMENT) : 0;
+                if (mIsCreate || mHasAttachment != hasAttachment) {
+                    mDiffNoteValues.put(NoteColumns.HAS_ATTACHMENT, hasAttachment);
+                }
+                mHasAttachment = hasAttachment;
+
+                long modifiedDate = note.has(NoteColumns.MODIFIED_DATE) ? note
+                        .getLong(NoteColumns.MODIFIED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mModifiedDate != modifiedDate) {
+                    mDiffNoteValues.put(NoteColumns.MODIFIED_DATE, modifiedDate);
+                }
+                mModifiedDate = modifiedDate;
+
+                long parentId = note.has(NoteColumns.PARENT_ID) ? note
+                        .getLong(NoteColumns.PARENT_ID) : 0;
+                if (mIsCreate || mParentId != parentId) {
+                    mDiffNoteValues.put(NoteColumns.PARENT_ID, parentId);
+                }
+                mParentId = parentId;
+
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+
+                int widgetId = note.has(NoteColumns.WIDGET_ID) ? note.getInt(NoteColumns.WIDGET_ID)
+                        : AppWidgetManager.INVALID_APPWIDGET_ID;
+                if (mIsCreate || mWidgetId != widgetId) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_ID, widgetId);
+                }
+                mWidgetId = widgetId;
+
+                int widgetType = note.has(NoteColumns.WIDGET_TYPE) ? note
+                        .getInt(NoteColumns.WIDGET_TYPE) : Notes.TYPE_WIDGET_INVALIDE;
+                if (mIsCreate || mWidgetType != widgetType) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_TYPE, widgetType);
+                }
+                mWidgetType = widgetType;
+
+                long originParent = note.has(NoteColumns.ORIGIN_PARENT_ID) ? note
+                        .getLong(NoteColumns.ORIGIN_PARENT_ID) : 0;
+                if (mIsCreate || mOriginParent != originParent) {
+                    mDiffNoteValues.put(NoteColumns.ORIGIN_PARENT_ID, originParent);
+                }
+                mOriginParent = originParent;
+
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    SqlData sqlData = null;
+                    if (data.has(DataColumns.ID)) {
+                        long dataId = data.getLong(DataColumns.ID);
+                        for (SqlData temp : mDataList) {
+                            if (dataId == temp.getId()) {
+                                sqlData = temp;
+                            }
+                        }
+                    }
+
+                    if (sqlData == null) {
+                        sqlData = new SqlData(mContext);
+                        mDataList.add(sqlData);
+                    }
+
+                    sqlData.setContent(data);
+                }
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return false;
+        }
+        return true;
+    }
+
+    public JSONObject getContent() {
+        try {
+            JSONObject js = new JSONObject();
+
+            if (mIsCreate) {
+                Log.e(TAG, "it seems that we haven't created this in database yet");
+                return null;
+            }
+
+            JSONObject note = new JSONObject();
+            if (mType == Notes.TYPE_NOTE) {
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.ALERTED_DATE, mAlertDate);
+                note.put(NoteColumns.BG_COLOR_ID, mBgColorId);
+                note.put(NoteColumns.CREATED_DATE, mCreatedDate);
+                note.put(NoteColumns.HAS_ATTACHMENT, mHasAttachment);
+                note.put(NoteColumns.MODIFIED_DATE, mModifiedDate);
+                note.put(NoteColumns.PARENT_ID, mParentId);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.WIDGET_ID, mWidgetId);
+                note.put(NoteColumns.WIDGET_TYPE, mWidgetType);
+                note.put(NoteColumns.ORIGIN_PARENT_ID, mOriginParent);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+
+                JSONArray dataArray = new JSONArray();
+                for (SqlData sqlData : mDataList) {
+                    JSONObject data = sqlData.getContent();
+                    if (data != null) {
+                        dataArray.put(data);
+                    }
+                }
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+            } else if (mType == Notes.TYPE_FOLDER || mType == Notes.TYPE_SYSTEM) {
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+            }
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    public void setParentId(long id) {
+        mParentId = id;
+        mDiffNoteValues.put(NoteColumns.PARENT_ID, id);
+    }
+
+    public void setGtaskId(String gid) {
+        mDiffNoteValues.put(NoteColumns.GTASK_ID, gid);
+    }
+
+    public void setSyncId(long syncId) {
+        mDiffNoteValues.put(NoteColumns.SYNC_ID, syncId);
+    }
+
+    public void resetLocalModified() {
+        mDiffNoteValues.put(NoteColumns.LOCAL_MODIFIED, 0);
+    }
+
+    public long getId() {
+        return mId;
+    }
+
+    public long getParentId() {
+        return mParentId;
+    }
+
+    public String getSnippet() {
+        return mSnippet;
+    }
+
+    public boolean isNoteType() {
+        return mType == Notes.TYPE_NOTE;
+    }
+
+    public void commit(boolean validateVersion) {
+        if (mIsCreate) {
+            if (mId == INVALID_ID && mDiffNoteValues.containsKey(NoteColumns.ID)) {
+                mDiffNoteValues.remove(NoteColumns.ID);
+            }
+
+            Uri uri = mContentResolver.insert(Notes.CONTENT_NOTE_URI, mDiffNoteValues);
+            try {
+                mId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+            if (mId == 0) {
+                throw new IllegalStateException("Create thread id failed");
+            }
+
+            if (mType == Notes.TYPE_NOTE) {
+                for (SqlData sqlData : mDataList) {
+                    sqlData.commit(mId, false, -1);
+                }
+            }
+        } else {
+            if (mId <= 0 && mId != Notes.ID_ROOT_FOLDER && mId != Notes.ID_CALL_RECORD_FOLDER) {
+                Log.e(TAG, "No such note");
+                throw new IllegalStateException("Try to update note with invalid id");
+            }
+            if (mDiffNoteValues.size() > 0) {
+                mVersion ++;
+                int result = 0;
+                if (!validateVersion) {
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                            + NoteColumns.ID + "=?)", new String[] {
+                            String.valueOf(mId)
+                    });
+                } else {
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                                    + NoteColumns.ID + "=?) AND (" + NoteColumns.VERSION + "<=?)",
+                            new String[] {
+                                    String.valueOf(mId), String.valueOf(mVersion)
+                            });
+                }
+                if (result == 0) {
+                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
+                }
+            }
+
+            if (mType == Notes.TYPE_NOTE) {
+                for (SqlData sqlData : mDataList) {
+                    sqlData.commit(mId, validateVersion, mVersion);
+                }
+            }
+        }
+
+        // refresh local info
+        loadFromCursor(mId);
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+
+        mDiffNoteValues.clear();
+        mIsCreate = false;
+    }
+}
diff --git a/src/net/micode/notes/gtask/data/Task.java b/src/net/micode/notes/gtask/data/Task.java
new file mode 100644
index 0000000..bdb68e0
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/Task.java
@@ -0,0 +1,352 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+public class Task extends Node {
+    private static final String TAG = Task.class.getSimpleName();
+
+    private boolean mCompleted;
+
+    private String mNotes;
+
+    private JSONObject mMetaInfo;
+
+    private Task mPriorSibling;
+
+    private TaskList mParent;
+
+    public Task() {
+        super();
+        mCompleted = false;
+        mNotes = null;
+        mPriorSibling = null;
+        mParent = null;
+        mMetaInfo = null;
+    }
+
+
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mParent.getChildTaskIndex(this));
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_TASK);
+            if (getNotes() != null) {
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+            // parent_id
+            js.put(GTaskStringUtils.GTASK_JSON_PARENT_ID, mParent.getGid());
+
+            // dest_parent_type
+            js.put(GTaskStringUtils.GTASK_JSON_DEST_PARENT_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+
+            // list_id
+            js.put(GTaskStringUtils.GTASK_JSON_LIST_ID, mParent.getGid());
+
+            // prior_sibling_id
+            if (mPriorSibling != null) {
+                js.put(GTaskStringUtils.GTASK_JSON_PRIOR_SIBLING_ID, mPriorSibling.getGid());
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-create jsonobject");
+        }
+
+        return js;
+    }
+
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            if (getNotes() != null) {
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-update jsonobject");
+        }
+
+        return js;
+    }
+
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }
+
+                // notes
+                if (js.has(GTaskStringUtils.GTASK_JSON_NOTES)) {
+                    setNotes(js.getString(GTaskStringUtils.GTASK_JSON_NOTES));
+                }
+
+                // deleted
+                if (js.has(GTaskStringUtils.GTASK_JSON_DELETED)) {
+                    setDeleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_DELETED));
+                }
+
+                // completed
+                if (js.has(GTaskStringUtils.GTASK_JSON_COMPLETED)) {
+                    setCompleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_COMPLETED));
+                }
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get task content from jsonobject");
+            }
+        }
+    }
+
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)
+                || !js.has(GTaskStringUtils.META_HEAD_DATA)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is avaiable");
+        }
+
+        try {
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+            if (note.getInt(NoteColumns.TYPE) != Notes.TYPE_NOTE) {
+                Log.e(TAG, "invalid type");
+                return;
+            }
+
+            for (int i = 0; i < dataArray.length(); i++) {
+                JSONObject data = dataArray.getJSONObject(i);
+                if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                    setName(data.getString(DataColumns.CONTENT));
+                    break;
+                }
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    public JSONObject getLocalJSONFromContent() {
+        String name = getName();
+        try {
+            if (mMetaInfo == null) {
+                // new task created from web
+                if (name == null) {
+                    Log.w(TAG, "the note seems to be an empty one");
+                    return null;
+                }
+
+                JSONObject js = new JSONObject();
+                JSONObject note = new JSONObject();
+                JSONArray dataArray = new JSONArray();
+                JSONObject data = new JSONObject();
+                data.put(DataColumns.CONTENT, name);
+                dataArray.put(data);
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+                return js;
+            } else {
+                // synced task
+                JSONObject note = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+                JSONArray dataArray = mMetaInfo.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                        data.put(DataColumns.CONTENT, getName());
+                        break;
+                    }
+                }
+
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                return mMetaInfo;
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public void setMetaInfo(MetaData metaData) {
+        if (metaData != null && metaData.getNotes() != null) {
+            try {
+                mMetaInfo = new JSONObject(metaData.getNotes());
+            } catch (JSONException e) {
+                Log.w(TAG, e.toString());
+                mMetaInfo = null;
+            }
+        }
+    }
+
+    public int getSyncAction(Cursor c) {
+        try {
+            JSONObject noteInfo = null;
+            if (mMetaInfo != null && mMetaInfo.has(GTaskStringUtils.META_HEAD_NOTE)) {
+                noteInfo = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            }
+
+            if (noteInfo == null) {
+                Log.w(TAG, "it seems that note meta has been deleted");
+                return SYNC_ACTION_UPDATE_REMOTE;
+            }
+
+            if (!noteInfo.has(NoteColumns.ID)) {
+                Log.w(TAG, "remote note id seems to be deleted");
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+
+            // validate the note id now
+            if (c.getLong(SqlNote.ID_COLUMN) != noteInfo.getLong(NoteColumns.ID)) {
+                Log.w(TAG, "note id doesn't match");
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+
+            if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+                // there is no local update
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // no update both side
+                    return SYNC_ACTION_NONE;
+                } else {
+                    // apply remote to local
+                    return SYNC_ACTION_UPDATE_LOCAL;
+                }
+            } else {
+                // validate gtask id
+                if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                    Log.e(TAG, "gtask id doesn't match");
+                    return SYNC_ACTION_ERROR;
+                }
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // local modification only
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                } else {
+                    return SYNC_ACTION_UPDATE_CONFLICT;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+
+        return SYNC_ACTION_ERROR;
+    }
+
+    public boolean isWorthSaving() {
+        return mMetaInfo != null || (getName() != null && getName().trim().length() > 0)
+                || (getNotes() != null && getNotes().trim().length() > 0);
+    }
+
+    public void setCompleted(boolean completed) {
+        this.mCompleted = completed;
+    }
+
+    public void setNotes(String notes) {
+        this.mNotes = notes;
+    }
+
+    public void setPriorSibling(Task priorSibling) {
+        this.mPriorSibling = priorSibling;
+    }
+
+    public void setParent(TaskList parent) {
+        this.mParent = parent;
+    }
+
+    public boolean getCompleted() {
+        return this.mCompleted;
+    }
+
+    public String getNotes() {
+        return this.mNotes;
+    }
+
+    public Task getPriorSibling() {
+        return this.mPriorSibling;
+    }
+
+    public TaskList getParent() {
+        return this.mParent;
+    }
+
+}
diff --git a/src/net/micode/notes/gtask/data/TaskList.java b/src/net/micode/notes/gtask/data/TaskList.java
new file mode 100644
index 0000000..9dc2041
--- /dev/null
+++ b/src/net/micode/notes/gtask/data/TaskList.java
@@ -0,0 +1,398 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.data;
+
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+
+public class TaskList extends Node {
+    private static final String TAG = TaskList.class.getSimpleName();//tag标记
+
+    private int mIndex;//当前TaskList的指针
+
+    private ArrayList<Task> mChildren;//类中主要的保存数据的单元，用来实现一个以Task为元素的ArrayList
+
+    public TaskList() {
+        super();
+        mChildren = new ArrayList<Task>();
+        mIndex = 1;
+    }
+
+    /* (non-Javadoc)
+     * @see net.micode.notes.gtask.data.Node#getCreateAction(int)
+     * 生成并返回一个包含了一定数据的JSONObject实体
+     */
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mIndex);
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-create jsonobject");
+        }
+
+        return js;
+    }
+
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-update jsonobject");
+        }
+
+        return js;
+    }
+
+    /* (non-Javadoc)
+     * @see net.micode.notes.gtask.data.Node#getUpdateAction(int)
+     * 生成并返回一个包含了一定数据的JSONObject实体
+     */
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }
+
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get tasklist content from jsonobject");
+            }
+        }
+    }
+
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is avaiable");
+        }
+
+        try {
+            JSONObject folder = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+
+            if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                String name = folder.getString(NoteColumns.SNIPPET);
+                setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + name);
+            } else if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                if (folder.getLong(NoteColumns.ID) == Notes.ID_ROOT_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT);
+                else if (folder.getLong(NoteColumns.ID) == Notes.ID_CALL_RECORD_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                            + GTaskStringUtils.FOLDER_CALL_NOTE);
+                else
+                    Log.e(TAG, "invalid system folder");
+            } else {
+                Log.e(TAG, "error type");
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    public JSONObject getLocalJSONFromContent() {
+        try {
+            JSONObject js = new JSONObject();
+            JSONObject folder = new JSONObject();
+
+            String folderName = getName();
+            if (getName().startsWith(GTaskStringUtils.MIUI_FOLDER_PREFFIX))
+                folderName = folderName.substring(GTaskStringUtils.MIUI_FOLDER_PREFFIX.length(),
+                        folderName.length());
+            folder.put(NoteColumns.SNIPPET, folderName);
+            if (folderName.equals(GTaskStringUtils.FOLDER_DEFAULT)
+                    || folderName.equals(GTaskStringUtils.FOLDER_CALL_NOTE))
+                folder.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+            else
+                folder.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+
+            js.put(GTaskStringUtils.META_HEAD_NOTE, folder);
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public int getSyncAction(Cursor c) {
+        try {
+            if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+                // there is no local update
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // no update both side
+                    return SYNC_ACTION_NONE;
+                } else {
+                    // apply remote to local
+                    return SYNC_ACTION_UPDATE_LOCAL;
+                }
+            } else {
+                // validate gtask id
+                if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                    Log.e(TAG, "gtask id doesn't match");
+                    return SYNC_ACTION_ERROR;
+                }
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // local modification only
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                } else {
+                    // for folder conflicts, just apply local modification
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+
+        return SYNC_ACTION_ERROR;
+    }
+
+    /**
+     * @return
+     * 功能：获得TaskList的大小，即mChildren的大小
+     */
+    public int getChildTaskCount() {
+        return mChildren.size();
+    }
+
+    /**
+     * @param task
+     * @return 返回值为是否成功添加任务。
+     * 功能：在当前任务表末尾添加新的任务。
+     */
+    public boolean addChildTask(Task task) {
+        boolean ret = false;
+        if (task != null && !mChildren.contains(task)) {
+            ret = mChildren.add(task);
+            if (ret) {
+                // need to set prior sibling and parent
+                task.setPriorSibling(mChildren.isEmpty() ? null : mChildren
+                        .get(mChildren.size() - 1));
+                task.setParent(this);
+                //注意：每一次ArrayList的变化都要紧跟相关Task中PriorSibling的更改
+                //，接下来几个函数都有相关操作
+            }
+        }
+        return ret;
+    }
+    /**
+     * @param task
+     * @param index
+     * @return
+     * 功能：在当前任务表的指定位置添加新的任务。
+     */
+    public boolean addChildTask(Task task, int index) {
+        if (index < 0 || index > mChildren.size()) {
+            Log.e(TAG, "add child task: invalid index");
+            return false;
+        }
+
+        int pos = mChildren.indexOf(task);
+        if (task != null && pos == -1) {
+            mChildren.add(index, task);
+
+            // update the task list
+            Task preTask = null;
+            Task afterTask = null;
+            if (index != 0)
+                preTask = mChildren.get(index - 1);
+            if (index != mChildren.size() - 1)
+                afterTask = mChildren.get(index + 1);
+
+            task.setPriorSibling(preTask);
+            if (afterTask != null)
+                afterTask.setPriorSibling(task);
+        }
+
+        return true;
+    }
+
+    /**
+     * @param task
+     * @return 返回删除是否成功
+     * 功能：删除TaskList中的一个Task
+     */
+    public boolean removeChildTask(Task task) {
+        boolean ret = false;
+        int index = mChildren.indexOf(task);
+        if (index != -1) {
+            ret = mChildren.remove(task);
+
+            if (ret) {
+                // reset prior sibling and parent
+                task.setPriorSibling(null);
+                task.setParent(null);
+
+                // update the task list
+                if (index != mChildren.size()) {
+                    mChildren.get(index).setPriorSibling(
+                            index == 0 ? null : mChildren.get(index - 1));
+                }
+            }
+        }
+        return ret;
+    }
+
+    /**
+     * @param task
+     * @param index
+     * @return
+     * 功能：将当前TaskList中含有的某个Task移到index位置
+     */
+    public boolean moveChildTask(Task task, int index) {
+
+        if (index < 0 || index >= mChildren.size()) {
+            Log.e(TAG, "move child task: invalid index");
+            return false;
+        }
+
+        int pos = mChildren.indexOf(task);
+        if (pos == -1) {
+            Log.e(TAG, "move child task: the task should in the list");
+            return false;
+        }
+
+        if (pos == index)
+            return true;
+        return (removeChildTask(task) && addChildTask(task, index));
+        //利用已实现好的功能完成当下功能；
+    }
+
+    /**
+     * @param gid
+     * @return返回寻找结果
+     * 功能：按gid寻找Task
+     */
+    public Task findChildTaskByGid(String gid) {
+        for (int i = 0; i < mChildren.size(); i++) {
+            Task t = mChildren.get(i);
+            if (t.getGid().equals(gid)) {
+                return t;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * @param task
+     * @return
+     * 功能：返回指定Task的index
+     */
+    public int getChildTaskIndex(Task task) {
+        return mChildren.indexOf(task);
+    }
+    /**
+     * @param index
+     * @return
+     * 功能：返回指定index的Task
+     */
+    public Task getChildTaskByIndex(int index) {
+        if (index < 0 || index >= mChildren.size()) {
+            Log.e(TAG, "getTaskByIndex: invalid index");
+            return null;
+        }
+        return mChildren.get(index);
+    }
+    /**
+     * @param gid
+     * @return
+     * 功能：返回指定gid的Task
+     */
+    public Task getChilTaskByGid(String gid) {
+        for (Task task : mChildren) {//一种常见的ArrayList的遍历方法（四种，见精读笔记）
+            if (task.getGid().equals(gid))
+                return task;
+        }
+        return null;
+    }
+
+    public ArrayList<Task> getChildTaskList() {
+        return this.mChildren;
+    }
+
+    public void setIndex(int index) {
+        this.mIndex = index;
+    }
+
+    public int getIndex() {
+        return this.mIndex;
+    }
+}
diff --git a/src/net/micode/notes/gtask/exception/ActionFailureException.java b/src/net/micode/notes/gtask/exception/ActionFailureException.java
new file mode 100644
index 0000000..438f283
--- /dev/null
+++ b/src/net/micode/notes/gtask/exception/ActionFailureException.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Description：支持小米便签运行过程中的运行异常处理。
+ */
+package net.micode.notes.gtask.exception;
+
+
+public class ActionFailureException extends RuntimeException {
+    private static final long serialVersionUID = 4425249765923293627L;
+
+    /*
+     * serialVersionUID相当于java类的身份证。主要用于版本控制。
+     * serialVersionUID作用是序列化时保持版本的兼容性，即在版本升级时反序列化仍保持对象的唯一性。
+     * Made By Cuican
+     */
+    public ActionFailureException() {
+        super();
+    }
+
+    /*
+     * 在JAVA类中使用super来引用父类的成分，用this来引用当前对象.
+     * 如果一个类从另外一个类继承，我们new这个子类的实例对象的时候，这个子类对象里面会有一个父类对象。
+     * 怎么去引用里面的父类对象呢？使用super来引用
+     * 也就是说，此处super()以及super (paramString)可认为是Exception ()和Exception (paramString)
+     * Made By Cuican
+     */
+    public ActionFailureException(String paramString) {
+        super(paramString);
+    }
+
+    public ActionFailureException(String paramString, Throwable paramThrowable) {
+        super(paramString, paramThrowable);
+    }
+}
diff --git a/src/net/micode/notes/gtask/exception/NetworkFailureException.java b/src/net/micode/notes/gtask/exception/NetworkFailureException.java
new file mode 100644
index 0000000..3cd38a6
--- /dev/null
+++ b/src/net/micode/notes/gtask/exception/NetworkFailureException.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Description：支持小米便签运行过程中的网络异常处理。
+ */
+package net.micode.notes.gtask.exception;
+
+
+public class NetworkFailureException extends Exception {
+    private static final long serialVersionUID = 2107610287180234136L;
+
+    /*
+     * serialVersionUID相当于java类的身份证。主要用于版本控制。
+     * serialVersionUID作用是序列化时保持版本的兼容性，即在版本升级时反序列化仍保持对象的唯一性。
+     * Made By Cuican
+     */
+    public NetworkFailureException() {
+        super();
+    }
+
+    /*
+     * 在JAVA类中使用super来引用父类的成分，用this来引用当前对象.
+     * 如果一个类从另外一个类继承，我们new这个子类的实例对象的时候，这个子类对象里面会有一个父类对象。
+     * 怎么去引用里面的父类对象呢？使用super来引用
+     * 也就是说，此处super()以及super (paramString)可认为是Exception ()和Exception (paramString)
+     * Made By Cuican
+     */
+    public NetworkFailureException(String paramString) {
+        super(paramString);
+    }
+
+    public NetworkFailureException(String paramString, Throwable paramThrowable) {
+        super(paramString, paramThrowable);
+    }
+}
diff --git a/src/net/micode/notes/gtask/remote/GTaskASyncTask.java b/src/net/micode/notes/gtask/remote/GTaskASyncTask.java
new file mode 100644
index 0000000..b49b382
--- /dev/null
+++ b/src/net/micode/notes/gtask/remote/GTaskASyncTask.java
@@ -0,0 +1,131 @@
+
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package net.micode.notes.gtask.remote;
+/*异步操作类，实现GTask的异步操作过程
+ * 主要方法：
+ * private void showNotification(int tickerId, String content) 向用户提示当前同步的状态，是一个用于交互的方法
+ * protected Integer doInBackground(Void... unused) 此方法在后台线程执行，完成任务的主要工作，通常需要较长的时间
+ * protected void onProgressUpdate(String... progress)  可以使用进度条增加用户体验度。 此方法在主线程执行，用于显示任务执行的进度。
+ * protected void onPostExecute(Integer result)  相当于Handler 处理UI的方式，在这里面可以使用在doInBackground 得到的结果处理操作UI
+ */
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.os.AsyncTask;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesListActivity;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+
+public class GTaskASyncTask extends AsyncTask<Void, String, Integer> {
+
+    private static int GTASK_SYNC_NOTIFICATION_ID = 5234235;
+
+    public interface OnCompleteListener {
+        void onComplete();
+    }
+
+    private Context mContext;
+
+    private NotificationManager mNotifiManager;
+
+    private GTaskManager mTaskManager;
+
+    private OnCompleteListener mOnCompleteListener;
+
+    public GTaskASyncTask(Context context, OnCompleteListener listener) {
+        mContext = context;
+        mOnCompleteListener = listener;
+        mNotifiManager = (NotificationManager) mContext
+                .getSystemService(Context.NOTIFICATION_SERVICE);
+        mTaskManager = GTaskManager.getInstance();
+    }
+
+    public void cancelSync() {
+        mTaskManager.cancelSync();
+    }
+
+    public void publishProgess(String message) {// 发布进度单位，系统将会调用onProgressUpdate()方法更新这些值
+        publishProgress(new String[] {
+                message
+        });
+    }
+
+    private void showNotification(int tickerId, String content) {
+        Notification notification = new Notification(R.drawable.notification, mContext
+                .getString(tickerId), System.currentTimeMillis());
+        notification.defaults = Notification.DEFAULT_LIGHTS;// 调用系统自带灯光
+        notification.flags = Notification.FLAG_AUTO_CANCEL;// 点击清除按钮或点击通知后会自动消失
+        PendingIntent pendingIntent;//一个描述了想要启动一个Activity、Broadcast或是Service的意图
+        if (tickerId != R.string.ticker_success) {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, new Intent(mContext,
+                    NotesPreferenceActivity.class), 0);//一个描述了想要启动一个Activity、Broadcast或是Service的意图
+
+        } else {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, new Intent(mContext,
+                    NotesListActivity.class), 0);
+            //如果同步成功，那么从系统取得一个用于启动一个NotesListActivity的PendingIntent对象
+        }
+        notification.setLatestEventInfo(mContext, mContext.getString(R.string.app_name), content,
+                pendingIntent);
+        mNotifiManager.notify(GTASK_SYNC_NOTIFICATION_ID, notification);//通过NotificationManager对象的notify（）方法来执行一个notification的消息
+    }
+
+    @Override
+    protected Integer doInBackground(Void... unused) {
+        publishProgess(mContext.getString(R.string.sync_progress_login, NotesPreferenceActivity
+                .getSyncAccountName(mContext)));//利用getString,将把 NotesPreferenceActivity.getSyncAccountName(mContext))的字符串内容传进sync_progress_login中
+        return mTaskManager.sync(mContext, this);//进行后台同步具体操作
+    }
+
+    @Override
+    protected void onProgressUpdate(String... progress) {
+        showNotification(R.string.ticker_syncing, progress[0]);
+        if (mContext instanceof GTaskSyncService) {//instanceof 判断mContext是否是GTaskSyncService的实例
+            ((GTaskSyncService) mContext).sendBroadcast(progress[0]);
+        }
+    }
+
+    @Override
+    protected void onPostExecute(Integer result) {//用于在执行完后台任务后更新UI,显示结果
+        if (result == GTaskManager.STATE_SUCCESS) {
+            showNotification(R.string.ticker_success, mContext.getString(
+                    R.string.success_sync_account, mTaskManager.getSyncAccount()));
+            NotesPreferenceActivity.setLastSyncTime(mContext, System.currentTimeMillis());
+        } else if (result == GTaskManager.STATE_NETWORK_ERROR) {
+            showNotification(R.string.ticker_fail, mContext.getString(R.string.error_sync_network));
+        } else if (result == GTaskManager.STATE_INTERNAL_ERROR) {
+            showNotification(R.string.ticker_fail, mContext.getString(R.string.error_sync_internal));
+        } else if (result == GTaskManager.STATE_SYNC_CANCELLED) {
+            showNotification(R.string.ticker_cancel, mContext
+                    .getString(R.string.error_sync_cancelled));
+        }//几种不同情况下的结果显示
+        if (mOnCompleteListener != null) {
+            new Thread(new Runnable() {
+                public void run() {
+                    mOnCompleteListener.onComplete();
+                }
+//完成后的操作，使用onComplete()将所有值都重新初始化，相当于完成一次操作
+            }).start();
+        }
+    }
+}
diff --git a/src/net/micode/notes/gtask/remote/GTaskClient.java b/src/net/micode/notes/gtask/remote/GTaskClient.java
new file mode 100644
index 0000000..8a9191b
--- /dev/null
+++ b/src/net/micode/notes/gtask/remote/GTaskClient.java
@@ -0,0 +1,670 @@
+/*
+ * 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;
+
+
+/*
+ * 主要功能：实现GTASK的登录操作，进行GTASK任务的创建，创建任务列表，从网络上获取任务和任务列表的内容
+ * 主要使用类或技术：accountManager JSONObject HttpParams authToken Gid
+ */
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.accounts.AccountManagerFuture;
+import android.app.Activity;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.gtask.data.Node;
+import net.micode.notes.gtask.data.Task;
+import net.micode.notes.gtask.data.TaskList;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.gtask.exception.NetworkFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.ClientProtocolException;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.cookie.Cookie;
+import org.apache.http.impl.client.BasicCookieStore;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.params.BasicHttpParams;
+import org.apache.http.params.HttpConnectionParams;
+import org.apache.http.params.HttpParams;
+import org.apache.http.params.HttpProtocolParams;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.Inflater;
+import java.util.zip.InflaterInputStream;
+
+
+public class GTaskClient {
+    private static final String TAG = GTaskClient.class.getSimpleName();
+
+    private static final String GTASK_URL = "https://mail.google.com/tasks/";
+    //这个是指定的URL
+    private static final String GTASK_GET_URL = "https://mail.google.com/tasks/ig";
+
+    private static final String GTASK_POST_URL = "https://mail.google.com/tasks/r/ig";
+
+    private static GTaskClient mInstance = null;
+
+    private DefaultHttpClient mHttpClient;
+
+    private String mGetUrl;
+
+    private String mPostUrl;
+
+    private long mClientVersion;
+
+    private boolean mLoggedin;
+
+    private long mLastLoginTime;
+
+    private int mActionId;
+
+    private Account mAccount;
+
+    private JSONArray mUpdateArray;
+
+    private GTaskClient() {
+        mHttpClient = null;
+        mGetUrl = GTASK_GET_URL;
+        mPostUrl = GTASK_POST_URL;
+        mClientVersion = -1;
+        mLoggedin = false;
+        mLastLoginTime = 0;
+        mActionId = 1;
+        mAccount = null;
+        mUpdateArray = null;
+    }
+
+    /*用来获取的实例化对象
+     * 使用 getInstance()
+     * 返回mInstance这个实例化对象
+     */
+    public static synchronized GTaskClient getInstance() {
+        if (mInstance == null) {
+            mInstance = new GTaskClient();
+        }
+        return mInstance;
+    }
+
+    /*用来实现登录操作的函数，传入的参数是一个Activity
+     * 设置登录操作限制时间，如果超时则需要重新登录
+     * 有两种登录方式，使用用户自己的URL登录或者使用谷歌官方的URL登录
+     * 返回true或者false，即最后是否登陆成功
+     */
+    public boolean login(Activity activity) {
+
+        //判断距离最后一次登录操作是否超过5分钟
+        // we suppose that the cookie would expire after 5 minutes
+        // then we need to re-login
+        final long interval = 1000 * 60 * 5;
+        if (mLastLoginTime + interval < System.currentTimeMillis()) {
+            mLoggedin = false;
+        }
+
+        // need to re-login after account switch
+        if (mLoggedin
+                && !TextUtils.equals(getSyncAccount().name, NotesPreferenceActivity
+                .getSyncAccountName(activity))) {
+            mLoggedin = false;
+        }
+        //如果没超过时间，则不需要重新登录
+        if (mLoggedin) {
+            Log.d(TAG, "already logged in");
+            return true;
+        }
+
+//更新最后登录时间，改为系统当前的时间
+        mLastLoginTime = System.currentTimeMillis();
+        String authToken = loginGoogleAccount(activity, false);
+//判断是否登录到谷歌账户
+        if (authToken == null) {
+            Log.e(TAG, "login google account failed");
+            return false;
+        }
+
+        // login with custom domain if necessary
+        //尝试使用用户自己的域名登录
+        if (!(mAccount.name.toLowerCase().endsWith("gmail.com") || mAccount.name.toLowerCase()
+//将用户账号名改为统一格式（小写）后判断是否为一个谷歌账号地址
+                .endsWith("googlemail.com"))) {
+            StringBuilder url = new StringBuilder(GTASK_URL).append("a/");
+            int index = mAccount.name.indexOf('@') + 1;
+            String suffix = mAccount.name.substring(index);
+            url.append(suffix + "/");
+            mGetUrl = url.toString() + "ig";//设置用户对应的getUrl
+            mPostUrl = url.toString() + "r/ig";//设置用户对应的postUrl
+
+            if (tryToLoginGtask(activity, authToken)) {
+                mLoggedin = true;
+            }
+        }
+        // try to login with google official url
+        //如果用户账户无法登录，则使用谷歌官方的URI进行登录
+        if (!mLoggedin) {
+            mGetUrl = GTASK_GET_URL;
+            mPostUrl = GTASK_POST_URL;
+            if (!tryToLoginGtask(activity, authToken)) {
+                return false;
+            }
+        }
+
+        mLoggedin = true;
+        return true;
+    }
+    /*具体实现登录谷歌账户的方法
+     * 使用令牌机制
+     * 使用AccountManager来管理注册账号
+     * 返回值是账号的令牌
+     */
+    private String loginGoogleAccount(Activity activity, boolean invalidateToken) {
+        String authToken;
+        //令牌，是登录操作保证安全性的一个方法
+        AccountManager accountManager = AccountManager.get(activity);
+//AccountManager这个类给用户提供了集中注册账号的接口
+        Account[] accounts = accountManager.getAccountsByType("com.google");
+//获取全部以com.google结尾的account
+        if (accounts.length == 0) {
+            Log.e(TAG, "there is no available google account");
+            return null;
+        }
+
+        String accountName = NotesPreferenceActivity.getSyncAccountName(activity);
+        Account account = null;
+        //遍历获得的accounts信息，寻找已经记录过的账户信息
+        for (Account a : accounts) {
+            if (a.name.equals(accountName)) {
+                account = a;
+                break;
+            }
+        }
+        if (account != null) {
+            mAccount = account;
+        } else {
+            Log.e(TAG, "unable to get an account with the same name in the settings");
+            return null;
+        }
+        //获取选中账号的令牌
+        // get the token now
+        AccountManagerFuture<Bundle> accountManagerFuture = accountManager.getAuthToken(account,
+                "goanna_mobile", null, activity, null, null);
+        try {
+            Bundle authTokenBundle = accountManagerFuture.getResult();
+            authToken = authTokenBundle.getString(AccountManager.KEY_AUTHTOKEN);
+            //如果是invalidateToken，那么需要调用invalidateAuthToken(String, String)方法废除这个无效token
+            if (invalidateToken) {
+                accountManager.invalidateAuthToken("com.google", authToken);
+                loginGoogleAccount(activity, false);
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "get auth token failed");
+            authToken = null;
+        }
+
+        return authToken;
+    }
+    //尝试登陆Gtask，这只是一个预先判断令牌是否是有效以及是否能登上GTask的方法,而不是具体实现登陆的方法
+    private boolean tryToLoginGtask(Activity activity, String authToken) {
+        if (!loginGtask(authToken)) {
+            // maybe the auth token is out of authTokedate, now let's invalidate the
+            // token and try again
+            //删除过一个无效的authToken，申请一个新的后再次尝试登陆
+            authToken = loginGoogleAccount(activity, true);
+            if (authToken == null) {
+                Log.e(TAG, "login google account failed");
+                return false;
+            }
+
+            if (!loginGtask(authToken)) {
+                Log.e(TAG, "login gtask failed");
+                return false;
+            }
+        }
+        return true;
+    }
+
+    //实现登录GTask的具体操作
+    private boolean loginGtask(String authToken) {
+        int timeoutConnection = 10000;
+        int timeoutSocket = 15000;
+        //socket是一种通信连接实现数据的交换的端口
+        HttpParams httpParameters = new BasicHttpParams();
+//实例化一个新的HTTP参数类
+        HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
+//设置连接超时时间
+        HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
+//设置设置端口超时时间
+        mHttpClient = new DefaultHttpClient(httpParameters);
+        BasicCookieStore localBasicCookieStore = new BasicCookieStore();
+//设置本地cookie
+        mHttpClient.setCookieStore(localBasicCookieStore);
+        HttpProtocolParams.setUseExpectContinue(mHttpClient.getParams(), false);
+
+        // login gtask
+        try {
+            String loginUrl = mGetUrl + "?auth=" + authToken;
+//设置登录的url
+            HttpGet httpGet = new HttpGet(loginUrl);
+            //通过登录的uri实例化网页上资源的查找
+            HttpResponse response = null;
+            response = mHttpClient.execute(httpGet);
+            // get the cookie now
+            //获取CookieStore里存放的cookie,看如果存有“GTL(不知道什么意思)”，则说明有验证成功的有效的cookie
+            List<Cookie> cookies = mHttpClient.getCookieStore().getCookies();
+            boolean hasAuthCookie = false;
+            for (Cookie cookie : cookies) {
+                if (cookie.getName().contains("GTL")) {
+                    hasAuthCookie = true;
+                }
+            }
+            if (!hasAuthCookie) {
+                Log.w(TAG, "it seems that there is no auth cookie");
+            }
+//获取client的内容，具体操作是在返回的Content中截取从_setup(开始到)}</script>中间的字符串内容，也就是gtask_url的内容
+            String resString = getResponseContent(response.getEntity());
+            String jsBegin = "_setup(";
+            String jsEnd = ")}</script>";
+            int begin = resString.indexOf(jsBegin);
+            int end = resString.lastIndexOf(jsEnd);
+            String jsString = null;
+            if (begin != -1 && end != -1 && begin < end) {
+                jsString = resString.substring(begin + jsBegin.length(), end);
+            }
+            JSONObject js = new JSONObject(jsString);
+            mClientVersion = js.getLong("v");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return false;
+        } catch (Exception e) {
+            // simply catch all exceptions
+            Log.e(TAG, "httpget gtask_url failed");
+            return false;
+        }
+
+        return true;
+    }
+
+    private int getActionId() {
+        return mActionId++;
+    }
+
+    /*实例化创建一个用于向网络传输数据的对象
+     * 使用HttpPost类
+     * 返回一个httpPost实例化对象，但里面还没有内容
+     */
+    private HttpPost createHttpPost() {
+        HttpPost httpPost = new HttpPost(mPostUrl);
+        httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
+        httpPost.setHeader("AT", "1");
+        return httpPost;
+    }
+
+    /*通过URL获取响应后返回的数据，也就是网络上的数据和资源
+     * 使用getContentEncoding()获取网络上的资源和数据
+     * 返回值就是获取到的资源
+     */
+    private String getResponseContent(HttpEntity entity) throws IOException {
+        String contentEncoding = null;
+        if (entity.getContentEncoding() != null) {
+//通过URL得到HttpEntity对象，如果不为空则使用getContent（）方法创建一个流将数据从网络都过来
+            contentEncoding = entity.getContentEncoding().getValue();
+            Log.d(TAG, "encoding: " + contentEncoding);
+        }
+
+        InputStream input = entity.getContent();
+        if (contentEncoding != null && contentEncoding.equalsIgnoreCase("gzip")) {
+//GZIP是使用DEFLATE进行压缩数据的另一个压缩库
+            input = new GZIPInputStream(entity.getContent());
+        } else if (contentEncoding != null && contentEncoding.equalsIgnoreCase("deflate")) {
+//DEFLATE是一个无专利的压缩算法，它可以实现无损数据压缩
+            Inflater inflater = new Inflater(true);
+            input = new InflaterInputStream(entity.getContent(), inflater);
+        }
+
+        try {
+            InputStreamReader isr = new InputStreamReader(input);
+            BufferedReader br = new BufferedReader(isr);
+//是一个包装类，它可以包装字符流，将字符流放入缓存里，先把字符读到缓存里，到缓存满了时候，再读入内存，是为了提供读的效率而设计的
+            StringBuilder sb = new StringBuilder();
+
+            while (true) {
+                String buff = br.readLine();
+                if (buff == null) {
+                    return sb.toString();
+                }
+                sb = sb.append(buff);
+            }
+        } finally {
+            input.close();
+        }
+    }
+    /*通过JSON发送请求
+     * 请求的具体内容在json的实例化对象js中然后传入
+     * 利用UrlEncodedFormEntity entity和httpPost.setEntity(entity)方法把js中的内容放置到httpPost中
+     * 执行请求后使用getResponseContent方法得到返回的数据和资源
+     * 将资源再次放入json后返回
+     */
+    private JSONObject postRequest(JSONObject js) throws NetworkFailureException {
+        if (!mLoggedin) {//未登录
+            Log.e(TAG, "please login first");
+            throw new ActionFailureException("not logged in");
+        }
+        //实例化一个httpPost的对象用来向服务器传输数据，在这里就是发送请求，而请求的内容在js里
+        HttpPost httpPost = createHttpPost();
+        try {
+            LinkedList<BasicNameValuePair> list = new LinkedList<BasicNameValuePair>();
+            list.add(new BasicNameValuePair("r", js.toString()));
+            UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, "UTF-8");//UrlEncodedFormEntity()的形式比较单一，是普通的键值对
+            httpPost.setEntity(entity);
+            //执行这个请求
+            // execute the post
+            HttpResponse response = mHttpClient.execute(httpPost);
+            String jsString = getResponseContent(response.getEntity());
+            return new JSONObject(jsString);
+
+        } catch (ClientProtocolException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("postRequest failed");
+        } catch (IOException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("postRequest failed");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("unable to convert response content to jsonobject");
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("error occurs when posting request");
+        }
+    }
+    /*创建单个任务
+     * 传入参数是一个.gtask.data.Task包里Task类的对象
+     * 利用json获取Task里的内容,并且创建相应的jsPost
+     * 利用postRequest得到任务的返回信息
+     * 使用task.setGid设置task的new_ID
+     */
+    public void createTask(Task task) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            actionList.put(task.getCreateAction(getActionId()));
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            // post
+            JSONObject jsResponse = postRequest(jsPost);
+            JSONObject jsResult = (JSONObject) jsResponse.getJSONArray(
+                    GTaskStringUtils.GTASK_JSON_RESULTS).get(0);
+            task.setGid(jsResult.getString(GTaskStringUtils.GTASK_JSON_NEW_ID));
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("create task: handing jsonobject failed");
+        }
+    }
+    /*
+     * 创建一个任务列表，与createTask几乎一样，区别就是最后设置的是tasklist的gid
+     */
+    public void createTaskList(TaskList tasklist) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            actionList.put(tasklist.getCreateAction(getActionId()));
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            // post
+            JSONObject jsResponse = postRequest(jsPost);
+            JSONObject jsResult = (JSONObject) jsResponse.getJSONArray(
+                    GTaskStringUtils.GTASK_JSON_RESULTS).get(0);
+            tasklist.setGid(jsResult.getString(GTaskStringUtils.GTASK_JSON_NEW_ID));
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("create tasklist: handing jsonobject failed");
+        }
+    }
+    /*
+     * 同步更新操作
+     * 使用JSONObject进行数据存储，使用jsPost.put，Put的信息包括UpdateArray和ClientVersion
+     * 使用postRequest发送这个jspost,进行处理
+     */
+    public void commitUpdate() throws NetworkFailureException {
+        if (mUpdateArray != null) {
+            try {
+                JSONObject jsPost = new JSONObject();
+
+                // action_list
+                jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, mUpdateArray);
+
+                // client_version
+                jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+                postRequest(jsPost);
+                mUpdateArray = null;
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("commit update: handing jsonobject failed");
+            }
+        }
+    }
+    /*
+     * 添加更新的事项
+     * 调用commitUpdate()实现
+     */
+    public void addUpdateNode(Node node) throws NetworkFailureException {
+        if (node != null) {
+            // too many update items may result in an error
+            // set max to 10 items
+            if (mUpdateArray != null && mUpdateArray.length() > 10) {
+                commitUpdate();
+            }
+
+            if (mUpdateArray == null)
+                mUpdateArray = new JSONArray();
+            mUpdateArray.put(node.getUpdateAction(getActionId()));
+        }
+    }
+    /*
+     * 移动task,比如讲task移动到不同的task列表中去
+     * 通过getGid获取task所属列表的gid
+     * 通过JSONObject.put(String name, Object value)函数设置移动后的task的相关属性值，从而达到移动的目的
+     * 最后还是通过postRequest进行更新后的发送
+     */
+    public void moveTask(Task task, TaskList preParent, TaskList curParent)
+            throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+            JSONObject action = new JSONObject();
+
+            // action_list
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_MOVE);
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, getActionId());
+            action.put(GTaskStringUtils.GTASK_JSON_ID, task.getGid());
+            if (preParent == curParent && task.getPriorSibling() != null) {
+                // put prioring_sibing_id only if moving within the tasklist and
+                //设置优先级ID，只有当移动是发生在文件中
+                action.put(GTaskStringUtils.GTASK_JSON_PRIOR_SIBLING_ID, task.getPriorSibling());
+            }
+            action.put(GTaskStringUtils.GTASK_JSON_SOURCE_LIST, preParent.getGid());//设置移动前所属列表
+            action.put(GTaskStringUtils.GTASK_JSON_DEST_PARENT, curParent.getGid());//设置当前所属列表
+            if (preParent != curParent) {
+                // put the dest_list only if moving between tasklists
+                action.put(GTaskStringUtils.GTASK_JSON_DEST_LIST, curParent.getGid());
+            }
+            actionList.put(action);
+            //最后将ACTION_LIST加入到jsPost中
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            postRequest(jsPost);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("move task: handing jsonobject failed");
+        }
+    }
+    /*
+     * 删除操作节点
+     * 还是利用JSON
+     * 删除过后使用postRequest发送删除后的结果
+     */
+    public void deleteNode(Node node) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+
+            // action_list
+            node.setDeleted(true);
+            actionList.put(node.getUpdateAction(getActionId()));
+//这里会获取到删除操作的ID，加入到actionLiast中
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            postRequest(jsPost);
+            mUpdateArray = null;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("delete node: handing jsonobject failed");
+        }
+    }
+    /*
+     * 获取任务列表
+     * 首先通过GetURI使用getResponseContent从网上获取数据
+     * 然后筛选出"_setup("到)}</script>的部分，并且从中获取GTASK_JSON_LISTS的内容返回
+     */
+    public JSONArray getTaskLists() throws NetworkFailureException {
+        if (!mLoggedin) {
+            Log.e(TAG, "please login first");
+            throw new ActionFailureException("not logged in");
+        }
+
+        try {
+            HttpGet httpGet = new HttpGet(mGetUrl);
+            HttpResponse response = null;
+            response = mHttpClient.execute(httpGet);
+            //筛选工作，把筛选出的字符串放入jsString
+            // get the task list
+            String resString = getResponseContent(response.getEntity());
+            String jsBegin = "_setup(";
+            String jsEnd = ")}</script>";
+            int begin = resString.indexOf(jsBegin);
+            int end = resString.lastIndexOf(jsEnd);
+            String jsString = null;
+            if (begin != -1 && end != -1 && begin < end) {
+                jsString = resString.substring(begin + jsBegin.length(), end);
+            }
+            JSONObject js = new JSONObject(jsString);
+            return js.getJSONObject("t").getJSONArray(GTaskStringUtils.GTASK_JSON_LISTS);
+        } catch (ClientProtocolException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("gettasklists: httpget failed");
+        } catch (IOException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new NetworkFailureException("gettasklists: httpget failed");
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("get task lists: handing jasonobject failed");
+        }
+    }
+    /*
+     * 通过传入的TASKList的gid,从网络上获取相应属于这个任务列表的任务
+     */
+    public JSONArray getTaskList(String listGid) throws NetworkFailureException {
+        commitUpdate();
+        try {
+            JSONObject jsPost = new JSONObject();
+            JSONArray actionList = new JSONArray();
+            JSONObject action = new JSONObject();
+
+            // action_list
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_GETALL);
+            action.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, getActionId());
+            action.put(GTaskStringUtils.GTASK_JSON_LIST_ID, listGid);
+//这里设置为传入的listGid
+            action.put(GTaskStringUtils.GTASK_JSON_GET_DELETED, false);
+            actionList.put(action);
+            jsPost.put(GTaskStringUtils.GTASK_JSON_ACTION_LIST, actionList);
+
+            // client_version
+            jsPost.put(GTaskStringUtils.GTASK_JSON_CLIENT_VERSION, mClientVersion);
+
+            JSONObject jsResponse = postRequest(jsPost);
+            return jsResponse.getJSONArray(GTaskStringUtils.GTASK_JSON_TASKS);
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("get task list: handing jsonobject failed");
+        }
+    }
+
+    public Account getSyncAccount() {
+        return mAccount;
+    }
+    //重置更新的内容
+    public void resetUpdateArray() {
+        mUpdateArray = null;
+    }
+}
diff --git a/src/net/micode/notes/gtask/remote/GTaskManager.java b/src/net/micode/notes/gtask/remote/GTaskManager.java
new file mode 100644
index 0000000..e0d68fe
--- /dev/null
+++ b/src/net/micode/notes/gtask/remote/GTaskManager.java
@@ -0,0 +1,908 @@
+/*
+ * 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();
+
+            // init meta list first
+            mMetaList = null;
+            for (int i = 0; i < jsTaskLists.length(); i++) {
+                JSONObject object = jsTaskLists.getJSONObject(i);//JSONObject与JSONArray一个为对象，一个为数组。此处取出单个JASONObject
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                String name = object.getString(GTaskStringUtils.GTASK_JSON_NAME);
+
+                if (name
+                        .equals(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_META)) {
+                    mMetaList = new TaskList(); //MetaList意为元表,Tasklist类型，此处为初始化
+                    mMetaList.setContentByRemoteJSON(object);
+                    //将JSON中部分数据复制到自己定义的对象中相对应的数据：name->mname...
+                    // load meta data
+                    JSONArray jsMetas = client.getTaskList(gid);
+                    for (int j = 0; j < jsMetas.length(); j++) {
+                        object = (JSONObject) jsMetas.getJSONObject(j);
+                        MetaData metaData = new MetaData();
+                        metaData.setContentByRemoteJSON(object);
+                        //if not worth to save，metadata将不加入mMetaList
+                        if (metaData.isWorthSaving()) {
+                            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);
+                    //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();
+        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);
+//通过HashMap找到对应Gid的TaskList
+        if (preParentList != curParentList) {
+            preParentList.removeChildTask(task);
+            curParentList.addChildTask(task);
+            GTaskClient.getInstance().moveTask(task, preParentList, curParentList);
+        }
+    }
+
+    // clear local modified flag
+        sqlNote.resetLocalModified();
+    //commit到本地数据库
+        sqlNote.commit(true);
+}
+/**
+ * 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/net/micode/notes/gtask/remote/GTaskSyncService.java b/src/net/micode/notes/gtask/remote/GTaskSyncService.java
new file mode 100644
index 0000000..991c07b
--- /dev/null
+++ b/src/net/micode/notes/gtask/remote/GTaskSyncService.java
@@ -0,0 +1,145 @@
+/*
+ * 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;
+/*
+ * 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
+ */
+import android.app.Activity;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.IBinder;
+
+public class GTaskSyncService extends Service {
+    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/net/micode/notes/model/Note.java b/src/net/micode/notes/model/Note.java
index 6493cfd..cc9f74b 100644
--- a/src/net/micode/notes/model/Note.java
+++ b/src/net/micode/notes/model/Note.java
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+
 package net.micode.notes.model;
 
 import android.content.ContentProviderOperation;
diff --git a/src/net/micode/notes/model/WorkingNote.java b/src/net/micode/notes/model/WorkingNote.java
index 20daea0..10b87c0 100644
--- a/src/net/micode/notes/model/WorkingNote.java
+++ b/src/net/micode/notes/model/WorkingNote.java
@@ -32,6 +32,7 @@ import net.micode.notes.data.Notes.TextNote;
 import net.micode.notes.tool.ResourceParser.NoteBgResources;
 
 
+
 /**
  * WorkingNote类用于表示“工作中的笔记”，它包含笔记的基本信息、内容、模式等，并负责与数据库中的数据进行交互。
  */
diff --git a/src/net/micode/notes/tool/BackupUtils.java b/src/net/micode/notes/tool/BackupUtils.java
index b98aa44..f17a8a7 100644
--- a/src/net/micode/notes/tool/BackupUtils.java
+++ b/src/net/micode/notes/tool/BackupUtils.java
@@ -35,6 +35,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
 
+
 public class BackupUtils {
     private static final String TAG = "BackupUtils";  // 定义日志标签
     private static BackupUtils sInstance;  // 单例模式实例
diff --git a/src/net/micode/notes/tool/DataUtils.java b/src/net/micode/notes/tool/DataUtils.java
index a672ed5..58d581a 100644
--- a/src/net/micode/notes/tool/DataUtils.java
+++ b/src/net/micode/notes/tool/DataUtils.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.HashSet;
 
 
+
 public class DataUtils {
     public static final String TAG = "DataUtils";  // 日志标签
 
diff --git a/src/net/micode/notes/tool/GTaskStringUtils.java b/src/net/micode/notes/tool/GTaskStringUtils.java
index 2154f81..8dcd9e8 100644
--- a/src/net/micode/notes/tool/GTaskStringUtils.java
+++ b/src/net/micode/notes/tool/GTaskStringUtils.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.tool;
 
+
 public class GTaskStringUtils {
 
     // GTASK 相关的 JSON 字段名常量
diff --git a/src/net/micode/notes/tool/ResourceParser.java b/src/net/micode/notes/tool/ResourceParser.java
index b47d650..b86c5cc 100644
--- a/src/net/micode/notes/tool/ResourceParser.java
+++ b/src/net/micode/notes/tool/ResourceParser.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.tool;
 
+
 import android.content.Context;
 import android.preference.PreferenceManager;
 
diff --git a/src/net/micode/notes/ui/AlarmAlertActivity.java b/src/net/micode/notes/ui/AlarmAlertActivity.java
index 4e1e85d..a8c3b65 100644
--- a/src/net/micode/notes/ui/AlarmAlertActivity.java
+++ b/src/net/micode/notes/ui/AlarmAlertActivity.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.app.Activity;
 import android.app.AlertDialog;
 import android.content.Context;
@@ -40,10 +41,10 @@ import net.micode.notes.tool.DataUtils;
 import java.io.IOException;
 
 public class AlarmAlertActivity extends Activity implements OnClickListener, OnDismissListener {
-    private long mNoteId;               // 当前提醒相关的笔记 ID
-    private String mSnippet;            // 笔记的片段内容（用于提醒内容）
+    private long mNoteId;                // 当前提醒相关的笔记 ID
+    private String mSnippet;             // 笔记的片段内容（用于提醒内容）
     private static final int SNIPPET_PREW_MAX_LEN = 60;  // 片段内容的最大长度
-    MediaPlayer mPlayer;               // 媒体播放器，用于播放提醒声音
+    MediaPlayer mPlayer;                // 媒体播放器，用于播放提醒声音
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
diff --git a/src/net/micode/notes/ui/AlarmInitReceiver.java b/src/net/micode/notes/ui/AlarmInitReceiver.java
index 5478dbe..a8e31ef 100644
--- a/src/net/micode/notes/ui/AlarmInitReceiver.java
+++ b/src/net/micode/notes/ui/AlarmInitReceiver.java
@@ -28,6 +28,7 @@ import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 
 
+
 public class AlarmInitReceiver extends BroadcastReceiver {
 
     // 定义查询笔记的列，只查询 ID 和 ALERTED_DATE
diff --git a/src/net/micode/notes/ui/AlarmReceiver.java b/src/net/micode/notes/ui/AlarmReceiver.java
index 0fbf01d..fe66716 100644
--- a/src/net/micode/notes/ui/AlarmReceiver.java
+++ b/src/net/micode/notes/ui/AlarmReceiver.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
diff --git a/src/net/micode/notes/ui/DateTimePicker.java b/src/net/micode/notes/ui/DateTimePicker.java
index 2b825ab..8e0525a 100644
--- a/src/net/micode/notes/ui/DateTimePicker.java
+++ b/src/net/micode/notes/ui/DateTimePicker.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import java.text.DateFormatSymbols;
 import java.util.Calendar;
 
diff --git a/src/net/micode/notes/ui/DateTimePickerDialog.java b/src/net/micode/notes/ui/DateTimePickerDialog.java
index f0600ab..a2edde1 100644
--- a/src/net/micode/notes/ui/DateTimePickerDialog.java
+++ b/src/net/micode/notes/ui/DateTimePickerDialog.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import java.util.Calendar;
 
 import net.micode.notes.R;
diff --git a/src/net/micode/notes/ui/DropdownMenu.java b/src/net/micode/notes/ui/DropdownMenu.java
index a3d2688..1c0befc 100644
--- a/src/net/micode/notes/ui/DropdownMenu.java
+++ b/src/net/micode/notes/ui/DropdownMenu.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.content.Context;
 import android.view.Menu;
 import android.view.MenuItem;
diff --git a/src/net/micode/notes/ui/FoldersListAdapter.java b/src/net/micode/notes/ui/FoldersListAdapter.java
index 766b520..b228a90 100644
--- a/src/net/micode/notes/ui/FoldersListAdapter.java
+++ b/src/net/micode/notes/ui/FoldersListAdapter.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.content.Context;
 import android.database.Cursor;
 import android.view.View;
diff --git a/src/net/micode/notes/ui/NoteEditActivity.java b/src/net/micode/notes/ui/NoteEditActivity.java
index 6844460..60518d3 100644
--- a/src/net/micode/notes/ui/NoteEditActivity.java
+++ b/src/net/micode/notes/ui/NoteEditActivity.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.app.Activity;
 import android.app.AlarmManager;
 import android.app.AlertDialog;
diff --git a/src/net/micode/notes/ui/NoteEditText.java b/src/net/micode/notes/ui/NoteEditText.java
index cbb2a97..91d72f8 100644
--- a/src/net/micode/notes/ui/NoteEditText.java
+++ b/src/net/micode/notes/ui/NoteEditText.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.content.Context;
 import android.graphics.Rect;
 import android.text.Layout;
diff --git a/src/net/micode/notes/ui/NoteItemData.java b/src/net/micode/notes/ui/NoteItemData.java
index 5f78303..58cfe64 100644
--- a/src/net/micode/notes/ui/NoteItemData.java
+++ b/src/net/micode/notes/ui/NoteItemData.java
@@ -25,6 +25,7 @@ import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.tool.DataUtils;
 
+
 /**
  * NoteItemData 类用于封装数据库查询返回的笔记数据，将其转换为可操作的对象模型。
  * 此类提供了关于笔记的各种信息，如笔记的 ID、提醒日期、创建日期、附件、类型等。
diff --git a/src/net/micode/notes/ui/NotesListActivity.java b/src/net/micode/notes/ui/NotesListActivity.java
index 91e0878..c724929 100644
--- a/src/net/micode/notes/ui/NotesListActivity.java
+++ b/src/net/micode/notes/ui/NotesListActivity.java
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+
 package net.micode.notes.ui;
 
 import android.app.Activity;
diff --git a/src/net/micode/notes/ui/NotesListAdapter.java b/src/net/micode/notes/ui/NotesListAdapter.java
index e555c4e..46764bb 100644
--- a/src/net/micode/notes/ui/NotesListAdapter.java
+++ b/src/net/micode/notes/ui/NotesListAdapter.java
@@ -31,6 +31,7 @@ import java.util.HashSet;
 import java.util.Iterator;
 
 
+
 /**
  * 适配器类，用于在列表中展示笔记数据。
  * 继承自CursorAdapter，适配从数据库中查询的Cursor数据。
diff --git a/src/net/micode/notes/ui/NotesListItem.java b/src/net/micode/notes/ui/NotesListItem.java
index 59f6b9a..1fb0d32 100644
--- a/src/net/micode/notes/ui/NotesListItem.java
+++ b/src/net/micode/notes/ui/NotesListItem.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.content.Context;
 import android.text.format.DateUtils;
 import android.view.View;
diff --git a/src/net/micode/notes/ui/NotesPreferenceActivity.java b/src/net/micode/notes/ui/NotesPreferenceActivity.java
index fc865e6..678bd42 100644
--- a/src/net/micode/notes/ui/NotesPreferenceActivity.java
+++ b/src/net/micode/notes/ui/NotesPreferenceActivity.java
@@ -16,6 +16,7 @@
 
 package net.micode.notes.ui;
 
+
 import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.app.ActionBar;
diff --git a/src/net/micode/notes/widget/NoteWidgetProvider.java b/src/net/micode/notes/widget/NoteWidgetProvider.java
index 0f770dc..a76191f 100644
--- a/src/net/micode/notes/widget/NoteWidgetProvider.java
+++ b/src/net/micode/notes/widget/NoteWidgetProvider.java
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+
 package net.micode.notes.widget;
 
 import android.app.PendingIntent;
diff --git a/src/net/micode/notes/widget/NoteWidgetProvider_2x.java b/src/net/micode/notes/widget/NoteWidgetProvider_2x.java
index 820b334..27cf320 100644
--- a/src/net/micode/notes/widget/NoteWidgetProvider_2x.java
+++ b/src/net/micode/notes/widget/NoteWidgetProvider_2x.java
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+
 package net.micode.notes.widget;
 
 import android.appwidget.AppWidgetManager;
diff --git a/src/net/micode/notes/widget/NoteWidgetProvider_4x.java b/src/net/micode/notes/widget/NoteWidgetProvider_4x.java
index e451350..10d594d 100644
--- a/src/net/micode/notes/widget/NoteWidgetProvider_4x.java
+++ b/src/net/micode/notes/widget/NoteWidgetProvider_4x.java
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+
 package net.micode.notes.widget;
 
 import android.appwidget.AppWidgetManager;