diff --git a/ActionFailureException.java b/ActionFailureException.java
new file mode 100644
index 0000000..e69de29
diff --git a/GTaskASyncTask.java b/GTaskASyncTask.java
new file mode 100644
index 0000000..e69de29
diff --git a/MetaData.java b/MetaData.java
new file mode 100644
index 0000000..7b64f80
--- /dev/null
+++ b/MetaData.java
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// MetaData 类继承自 Task，用于处理任务的元数据信息
+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 {
+    // 日志标签，用于日志记录
+    private final static String TAG = MetaData.class.getSimpleName();
+
+    // 存储相关的 Google 任务 ID
+    private String mRelatedGid = null;
+
+    /**
+     * 设置元数据信息
+     * 
+     * @param gid 相关的 Google 任务 ID
+     * @param metaInfo 元数据信息，以 JSON 格式表示
+     */
+    public void setMeta(String gid, JSONObject metaInfo) {
+        try {
+            // 将 Google 任务 ID 添加到元数据中
+            metaInfo.put(GTaskStringUtils.META_HEAD_GTASK_ID, gid);
+        } catch (JSONException e) {
+            // 如果添加失败，记录错误日志
+            Log.e(TAG, "failed to put related gid");
+        }
+        // 将元数据转换为字符串并设置为笔记
+        setNotes(metaInfo.toString());
+        // 设置元数据的名称
+        setName(GTaskStringUtils.META_NOTE_NAME);
+    }
+
+    /**
+     * 获取相关的 Google 任务 ID
+     * 
+     * @return 返回 Google 任务 ID
+     */
+    public String getRelatedGid() {
+        return mRelatedGid;
+    }
+
+    /**
+     * 判断元数据是否值得保存
+     * 
+     * @return 如果笔记不为空，则返回 true，否则返回 false
+     */
+    @Override
+    public boolean isWorthSaving() {
+        return getNotes() != null;
+    }
+
+    /**
+     * 从远程 JSON 设置内容
+     * 
+     * @param js 远程 JSON 对象
+     */
+    @Override
+    public void setContentByRemoteJSON(JSONObject js) {
+        super.setContentByRemoteJSON(js);
+        if (getNotes() != null) {
+            try {
+                // 解析笔记以获取 Google 任务 ID
+                JSONObject metaInfo = new JSONObject(getNotes().trim());
+                mRelatedGid = metaInfo.getString(GTaskStringUtils.META_HEAD_GTASK_ID);
+            } catch (JSONException e) {
+                // 如果解析失败，记录警告日志
+                Log.w(TAG, "failed to get related gid");
+                mRelatedGid = null;
+            }
+        }
+    }
+
+    /**
+     * 从本地 JSON 设置内容
+     * 此方法不应被调用
+     * 
+     * @param js 本地 JSON 对象
+     */
+    @Override
+    public void setContentByLocalJSON(JSONObject js) {
+        // 此方法不应被调用
+        throw new IllegalAccessError("MetaData:setContentByLocalJSON should not be called");
+    }
+
+    /**
+     * 从内容中获取本地 JSON
+     * 此方法不应被调用
+     * 
+     * @return 永远不会返回，将抛出异常
+     */
+    @Override
+    public JSONObject getLocalJSONFromContent() {
+        throw new IllegalAccessError("MetaData:getLocalJSONFromContent should not be called");
+    }
+
+    /**
+     * 基于游标获取同步操作
+     * 此方法不应被调用
+     * 
+     * @param c 游标
+     * @return 永远不会返回，将抛出异常
+     */
+    @Override
+    public int getSyncAction(Cursor c) {
+        throw new IllegalAccessError("MetaData:getSyncAction should not be called");
+    }
+}
diff --git a/NetworkFailureException.java b/NetworkFailureException.java
new file mode 100644
index 0000000..e69de29
diff --git a/Node.java b/Node.java
new file mode 100644
index 0000000..79259a3
--- /dev/null
+++ b/Node.java
@@ -0,0 +1,126 @@
+/*
+ * 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.
+ */
+
+/**
+ * 抽象类Node代表一个基本的节点对象，提供了基本的属性和方法用于操作和同步节点数据
+ * 主要用于笔记或任务的同步处理
+ */
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import org.json.JSONObject;
+
+public abstract class Node {
+    // 定义同步操作类型常量
+    public static final int SYNC_ACTION_NONE = 0;
+    public static final int SYNC_ACTION_ADD_REMOTE = 1;
+    public static final int SYNC_ACTION_ADD_LOCAL = 2;
+    public static final int SYNC_ACTION_DEL_REMOTE = 3;
+    public static final int SYNC_ACTION_DEL_LOCAL = 4;
+    public static final int SYNC_ACTION_UPDATE_REMOTE = 5;
+    public static final int SYNC_ACTION_UPDATE_LOCAL = 6;
+    public static final int SYNC_ACTION_UPDATE_CONFLICT = 7;
+    public static final int SYNC_ACTION_ERROR = 8;
+
+    // 节点的基本属性
+    private String mGid;
+    private String mName;
+    private long mLastModified;
+    private boolean mDeleted;
+
+    /**
+     * 默认构造方法，初始化节点的基本属性
+     */
+    public Node() {
+        mGid = null;
+        mName = "";
+        mLastModified = 0;
+        mDeleted = false;
+    }
+
+    /**
+     * 根据操作ID生成创建操作的JSON对象
+     * @param actionId 操作ID，表示需要执行的同步操作类型
+     * @return 返回一个包含创建操作信息的JSON对象
+     */
+    public abstract JSONObject getCreateAction(int actionId);
+
+    /**
+     * 根据操作ID生成更新操作的JSON对象
+     * @param actionId 操作ID，表示需要执行的同步操作类型
+     * @return 返回一个包含更新操作信息的JSON对象
+     */
+    public abstract JSONObject getUpdateAction(int actionId);
+
+    /**
+     * 通过远程JSON对象设置节点内容
+     * @param js 远程JSON对象，包含节点的最新数据
+     */
+    public abstract void setContentByRemoteJSON(JSONObject js);
+
+    /**
+     * 通过本地JSON对象设置节点内容
+     * @param js 本地JSON对象，包含节点的现有数据
+     */
+    public abstract void setContentByLocalJSON(JSONObject js);
+
+    /**
+     * 从节点内容生成本地JSON对象
+     * @return 返回一个包含节点当前状态的JSON对象
+     */
+    public abstract JSONObject getLocalJSONFromContent();
+
+    /**
+     * 根据数据库游标确定同步操作类型
+     * @param c 数据库游标，指向查询到的节点数据
+     * @return 返回一个整数，表示需要执行的同步操作类型
+     */
+    public abstract int getSyncAction(Cursor c);
+
+    // 以下为节点属性的getter和setter方法
+    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/NotesDatabaseHelper.java b/NotesDatabaseHelper.java
new file mode 100644
index 0000000..dc77b6b
--- /dev/null
+++ b/NotesDatabaseHelper.java
@@ -0,0 +1,273 @@
+
+// 创建笔记表的SQL语句
+private static final String CREATE_NOTE_TABLE_SQL = "CREATE TABLE " + TABLE.NOTE + " ("
+        + NoteColumns.ID + " TEXT PRIMARY KEY, "
+        + NoteColumns.TITLE + " TEXT NOT NULL, "
+        + NoteColumns.CONTENT + " TEXT NOT NULL, "
+        + NoteColumns.CREATED_DATE + " INTEGER NOT NULL, "
+        + NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL, "
+        + NoteColumns.TYPE + " INTEGER NOT NULL, "
+        + NoteColumns.PARENT_ID + " TEXT NOT NULL, "
+        + NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT '', "
+        + NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0"
+        + ");";
+
+// 创建与笔记表相关的触发器的SQL语句
+private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER = "CREATE TRIGGER increase_folder_count_on_update AFTER UPDATE ON " + TABLE.NOTE
+        + " BEGIN"
+        + " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.COUNT + " = " + NoteColumns.COUNT + " + 1"
+        + " WHERE " + NoteColumns.ID + " = new." + NoteColumns.PARENT_ID + ";"
+        + " END;";
+// 类似的触发器SQL语句省略...
+
+// 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 AUTOINCREMENT, "
+        + DataColumns.Note_ID + " TEXT NOT NULL, "
+        + DataColumns.TYPE + " INTEGER NOT NULL, "
+        + DataColumns.CONTENT + " TEXT NOT NULL, "
+        + DataColumns.CREATED_DATE + " INTEGER NOT NULL"
+        + ");";
+
+// 创建与数据表相关的触发器的SQL语句
+private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER = "CREATE TRIGGER update_note_content_on_insert AFTER INSERT ON " + TABLE.DATA
+        + " BEGIN"
+        + " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.CONTENT + " = new." + DataColumns.CONTENT
+        + " WHERE " + NoteColumns.ID + " = new." + DataColumns.Note_ID + ";"
+        + " END;";
+// 类似的触发器SQL语句省略...
+
+// 在数据表上创建索引的SQL语句
+private static final String CREATE_DATA_NOTE_ID_INDEX_SQL = "CREATE INDEX " + TABLE.DATA + "_note_id_index ON "
+        + TABLE.DATA + " (" + DataColumns.Note_ID + ");";
+
+// 删除触发器的SQL语句
+private static final String DROP_TRIGGER_SQL = "DROP TRIGGER IF EXISTS %s;";
+
+// 插入系统文件夹的SQL语句
+private static final String INSERT_SYSTEM_FOLDER_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.PARENT_ID + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?);";
+
+// 更新笔记表的SQL语句
+private static final String UPDATE_NOTE_TABLE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TITLE + " = ?, "
+        + NoteColumns.CONTENT + " = ?, "
+        + NoteColumns.MODIFIED_DATE + " = ?, "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除笔记的SQL语句
+private static final String DELETE_NOTE_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记的SQL语句
+private static final String QUERY_NOTES_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按ID查询笔记的SQL语句
+private static final String QUERY_NOTE_BY_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记的最大版本的SQL语句
+private static final String QUERY_MAX_VERSION_SQL = "SELECT MAX(" + NoteColumns.VERSION + ") FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记版本的SQL语句
+private static final String UPDATE_NOTE_VERSION_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.VERSION + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除旧笔记的SQL语句
+private static final String DELETE_OLD_NOTES_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.VERSION + " < ?;";
+
+// 创建新版本笔记的SQL语句
+private static final String CREATE_NEW_VERSION_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.PARENT_ID + ", "
+        + NoteColumns.GTASK_ID + ", "
+        + NoteColumns.VERSION + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?);";
+
+// 按类型查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TYPE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TYPE + " = ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按标题查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TITLE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TITLE + " LIKE ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按内容查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_CONTENT_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.CONTENT + " LIKE ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按日期范围查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_DATE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.CREATED_DATE + " BETWEEN ? AND ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按GTASK ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_GTASK_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.GTASK_ID + " = ?;";
+
+// 更新笔记的GTASK ID的SQL语句
+private static final String UPDATE_NOTE_GTASK_ID_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.GTASK_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询回收站中的笔记的SQL语句
+private static final String QUERY_TRASH_NOTES_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = " + Notes.ID_TRASH_FOLER
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 从回收站恢复笔记的SQL语句
+private static final String RESTORE_NOTE_FROM_TRASH_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 永久删除笔记的SQL语句
+private static final String PERMANENTLY_DELETE_NOTE_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询文件夹中笔记数量的SQL语句
+private static final String QUERY_FOLDER_COUNT_SQL = "SELECT COUNT(*) FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 更新文件夹中笔记数量的SQL语句
+private static final String UPDATE_FOLDER_COUNT_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.COUNT + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记表中的最大ID的SQL语句
+private static final String QUERY_MAX_ID_SQL = "SELECT MAX(" + NoteColumns.ID + ") FROM " + TABLE.NOTE;
+
+// 插入新笔记的SQL语句
+private static final String INSERT_NOTE_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.PARENT_ID + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?);";
+
+// 更新笔记标题的SQL语句
+private static final String UPDATE_NOTE_TITLE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TITLE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记内容的SQL语句
+private static final String UPDATE_NOTE_CONTENT_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.CONTENT + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记修改日期的SQL语句
+private static final String UPDATE_NOTE_MODIFIED_DATE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.MODIFIED_DATE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记父ID的SQL语句
+private static final String UPDATE_NOTE_PARENT_ID_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除文件夹中的笔记的SQL语句
+private static final String DELETE_NOTES_IN_FOLDER_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 按父ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_PARENT_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 更新笔记类型的SQL语句
+private static final String UPDATE_NOTE_TYPE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TYPE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 按类型和父ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TYPE_AND_PARENT_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TYPE + " = ? AND "
+        + NoteColumns.PARENT_ID + " = ?;"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+/**
+ * 构造函数，初始化数据库帮助器。
+ *
+ * @param context 上下文对象
+ */
+public NotesDatabaseHelper(Context context) {
+    super(context, DB_NAME, null, DB_VERSION);
+}
+
+/**
+ * 创建笔记表。
+ *
+ * @param db 数据库对象
+ */
+public void createNoteTable(SQLiteDatabase db) {
+    db.execSQL(CREATE_NOTE_TABLE_SQL);
+    reCreateNoteTableTriggers(db);
+    createSystemFolder(db);
+    Log.d(TAG, "note table has been created");
+}
+
+/**
+ * 重新创建笔记表的触发器。
+ *
+ * @param db 数据库对象
+ */
+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。
+ *
+ * @param db 数据库对象
+ */
+private void createSystemFolder(SQLiteDatabase db) {
+    ContentValues values = new ContentValues();
+
+    /**
+     * 通话记录文件夹，用于存储通话笔记
+     */
+    values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+
+    /**
+     * 根文件夹，作为默认文件夹
+     */
+    values.clear();
+    values.put(NoteColumns.ID, Notes.ID
\ No newline at end of file
diff --git a/NotesProvider.java b/NotesProvider.java
new file mode 100644
index 0000000..dc77b6b
--- /dev/null
+++ b/NotesProvider.java
@@ -0,0 +1,273 @@
+
+// 创建笔记表的SQL语句
+private static final String CREATE_NOTE_TABLE_SQL = "CREATE TABLE " + TABLE.NOTE + " ("
+        + NoteColumns.ID + " TEXT PRIMARY KEY, "
+        + NoteColumns.TITLE + " TEXT NOT NULL, "
+        + NoteColumns.CONTENT + " TEXT NOT NULL, "
+        + NoteColumns.CREATED_DATE + " INTEGER NOT NULL, "
+        + NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL, "
+        + NoteColumns.TYPE + " INTEGER NOT NULL, "
+        + NoteColumns.PARENT_ID + " TEXT NOT NULL, "
+        + NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT '', "
+        + NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0"
+        + ");";
+
+// 创建与笔记表相关的触发器的SQL语句
+private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER = "CREATE TRIGGER increase_folder_count_on_update AFTER UPDATE ON " + TABLE.NOTE
+        + " BEGIN"
+        + " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.COUNT + " = " + NoteColumns.COUNT + " + 1"
+        + " WHERE " + NoteColumns.ID + " = new." + NoteColumns.PARENT_ID + ";"
+        + " END;";
+// 类似的触发器SQL语句省略...
+
+// 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 AUTOINCREMENT, "
+        + DataColumns.Note_ID + " TEXT NOT NULL, "
+        + DataColumns.TYPE + " INTEGER NOT NULL, "
+        + DataColumns.CONTENT + " TEXT NOT NULL, "
+        + DataColumns.CREATED_DATE + " INTEGER NOT NULL"
+        + ");";
+
+// 创建与数据表相关的触发器的SQL语句
+private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER = "CREATE TRIGGER update_note_content_on_insert AFTER INSERT ON " + TABLE.DATA
+        + " BEGIN"
+        + " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.CONTENT + " = new." + DataColumns.CONTENT
+        + " WHERE " + NoteColumns.ID + " = new." + DataColumns.Note_ID + ";"
+        + " END;";
+// 类似的触发器SQL语句省略...
+
+// 在数据表上创建索引的SQL语句
+private static final String CREATE_DATA_NOTE_ID_INDEX_SQL = "CREATE INDEX " + TABLE.DATA + "_note_id_index ON "
+        + TABLE.DATA + " (" + DataColumns.Note_ID + ");";
+
+// 删除触发器的SQL语句
+private static final String DROP_TRIGGER_SQL = "DROP TRIGGER IF EXISTS %s;";
+
+// 插入系统文件夹的SQL语句
+private static final String INSERT_SYSTEM_FOLDER_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.PARENT_ID + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?);";
+
+// 更新笔记表的SQL语句
+private static final String UPDATE_NOTE_TABLE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TITLE + " = ?, "
+        + NoteColumns.CONTENT + " = ?, "
+        + NoteColumns.MODIFIED_DATE + " = ?, "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除笔记的SQL语句
+private static final String DELETE_NOTE_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记的SQL语句
+private static final String QUERY_NOTES_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按ID查询笔记的SQL语句
+private static final String QUERY_NOTE_BY_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记的最大版本的SQL语句
+private static final String QUERY_MAX_VERSION_SQL = "SELECT MAX(" + NoteColumns.VERSION + ") FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记版本的SQL语句
+private static final String UPDATE_NOTE_VERSION_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.VERSION + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除旧笔记的SQL语句
+private static final String DELETE_OLD_NOTES_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.VERSION + " < ?;";
+
+// 创建新版本笔记的SQL语句
+private static final String CREATE_NEW_VERSION_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.PARENT_ID + ", "
+        + NoteColumns.GTASK_ID + ", "
+        + NoteColumns.VERSION + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?);";
+
+// 按类型查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TYPE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TYPE + " = ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按标题查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TITLE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TITLE + " LIKE ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按内容查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_CONTENT_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.CONTENT + " LIKE ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按日期范围查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_DATE_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.CREATED_DATE + " BETWEEN ? AND ?"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 按GTASK ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_GTASK_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.GTASK_ID + " = ?;";
+
+// 更新笔记的GTASK ID的SQL语句
+private static final String UPDATE_NOTE_GTASK_ID_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.GTASK_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询回收站中的笔记的SQL语句
+private static final String QUERY_TRASH_NOTES_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = " + Notes.ID_TRASH_FOLER
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+// 从回收站恢复笔记的SQL语句
+private static final String RESTORE_NOTE_FROM_TRASH_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 永久删除笔记的SQL语句
+private static final String PERMANENTLY_DELETE_NOTE_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询文件夹中笔记数量的SQL语句
+private static final String QUERY_FOLDER_COUNT_SQL = "SELECT COUNT(*) FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 更新文件夹中笔记数量的SQL语句
+private static final String UPDATE_FOLDER_COUNT_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.COUNT + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 查询笔记表中的最大ID的SQL语句
+private static final String QUERY_MAX_ID_SQL = "SELECT MAX(" + NoteColumns.ID + ") FROM " + TABLE.NOTE;
+
+// 插入新笔记的SQL语句
+private static final String INSERT_NOTE_SQL = "INSERT INTO " + TABLE.NOTE + " ("
+        + NoteColumns.ID + ", "
+        + NoteColumns.TITLE + ", "
+        + NoteColumns.CONTENT + ", "
+        + NoteColumns.CREATED_DATE + ", "
+        + NoteColumns.MODIFIED_DATE + ", "
+        + NoteColumns.TYPE + ", "
+        + NoteColumns.PARENT_ID + ")"
+        + " VALUES (?, ?, ?, ?, ?, ?, ?);";
+
+// 更新笔记标题的SQL语句
+private static final String UPDATE_NOTE_TITLE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TITLE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记内容的SQL语句
+private static final String UPDATE_NOTE_CONTENT_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.CONTENT + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记修改日期的SQL语句
+private static final String UPDATE_NOTE_MODIFIED_DATE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.MODIFIED_DATE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 更新笔记父ID的SQL语句
+private static final String UPDATE_NOTE_PARENT_ID_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.PARENT_ID + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 删除文件夹中的笔记的SQL语句
+private static final String DELETE_NOTES_IN_FOLDER_SQL = "DELETE FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 按父ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_PARENT_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.PARENT_ID + " = ?;";
+
+// 更新笔记类型的SQL语句
+private static final String UPDATE_NOTE_TYPE_SQL = "UPDATE " + TABLE.NOTE + " SET "
+        + NoteColumns.TYPE + " = ?"
+        + " WHERE " + NoteColumns.ID + " = ?;";
+
+// 按类型和父ID查询笔记的SQL语句
+private static final String QUERY_NOTES_BY_TYPE_AND_PARENT_ID_SQL = "SELECT * FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.TYPE + " = ? AND "
+        + NoteColumns.PARENT_ID + " = ?;"
+        + " ORDER BY " + NoteColumns.MODIFIED_DATE + " DESC;";
+
+/**
+ * 构造函数，初始化数据库帮助器。
+ *
+ * @param context 上下文对象
+ */
+public NotesDatabaseHelper(Context context) {
+    super(context, DB_NAME, null, DB_VERSION);
+}
+
+/**
+ * 创建笔记表。
+ *
+ * @param db 数据库对象
+ */
+public void createNoteTable(SQLiteDatabase db) {
+    db.execSQL(CREATE_NOTE_TABLE_SQL);
+    reCreateNoteTableTriggers(db);
+    createSystemFolder(db);
+    Log.d(TAG, "note table has been created");
+}
+
+/**
+ * 重新创建笔记表的触发器。
+ *
+ * @param db 数据库对象
+ */
+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。
+ *
+ * @param db 数据库对象
+ */
+private void createSystemFolder(SQLiteDatabase db) {
+    ContentValues values = new ContentValues();
+
+    /**
+     * 通话记录文件夹，用于存储通话笔记
+     */
+    values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+
+    /**
+     * 根文件夹，作为默认文件夹
+     */
+    values.clear();
+    values.put(NoteColumns.ID, Notes.ID
\ No newline at end of file
diff --git a/SqlData.java b/SqlData.java
new file mode 100644
index 0000000..150a6f8
--- /dev/null
+++ b/SqlData.java
@@ -0,0 +1,192 @@
+import net.micode.notes.gtask.exception.ActionFailureException;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * SqlData类用于处理与数据库相关的操作，主要负责将JSON数据与数据库记录进行相互转换和更新
+ */
+public class SqlData {
+    // 日志标签，用于标识日志来源
+    private static final String TAG = SqlData.class.getSimpleName();
+    
+    // 无效的ID标识，用于表示未初始化或无效的数据库ID
+    private static final int INVALID_ID = -99999;
+    
+    // 数据库查询投影，定义了需要查询的列
+    public static final String[] PROJECTION_DATA = new String[] {
+            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
+            DataColumns.DATA3
+    };
+    
+    // 下面是数据库查询结果中各列的索引位置
+    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;
+    
+    // ContentResolver用于访问内容提供者
+    private ContentResolver mContentResolver;
+    
+    // 标识当前对象是否是新创建的
+    private boolean mIsCreate;
+    
+    // 下面是数据库记录的各项字段
+    private long mDataId;
+    private String mDataMimeType;
+    private String mDataContent;
+    private long mDataContentData1;
+    private String mDataContentData3;
+    
+    // 用于存储待更新的数据库记录值
+    private ContentValues mDiffDataValues;
+    
+    /**
+     * 构造函数，用于创建新的SqlData对象
+     * @param context 上下文环境，用于获取ContentResolver
+     */
+    public SqlData(Context context) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mDataId = INVALID_ID;
+        mDataMimeType = DataConstants.NOTE;
+        mDataContent = "";
+        mDataContentData1 = 0;
+        mDataContentData3 = "";
+        mDiffDataValues = new ContentValues();
+    }
+    
+    /**
+     * 构造函数，用于从现有的数据库记录创建SqlData对象
+     * @param context 上下文环境，用于获取ContentResolver
+     * @param c 游标对象，指向数据库记录
+     */
+    public SqlData(Context context, Cursor c) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDiffDataValues = new ContentValues();
+    }
+    
+    /**
+     * 从游标中加载数据库记录
+     * @param c 游标对象，指向数据库记录
+     */
+    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);
+    }
+    
+    /**
+     * 设置内容，从JSONObject中提取数据并更新到SqlData对象
+     * @param js 包含数据的JSONObject对象
+     * @throws JSONException 当JSON操作失败时抛出
+     */
+    public void setContent(JSONObject js) throws JSONException {
+        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;
+    }
+    
+    /**
+     * 获取内容，将SqlData对象的数据封装到JSONObject中
+     * @return 包含数据的JSONObject对象
+     * @throws JSONException 当JSON操作失败时抛出
+     */
+    public JSONObject getContent() throws JSONException {
+        if (mIsCreate) {
+            Log.e(TAG, "it seems that we haven't created this in database yet");
+            return null;
+        }
+        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;
+    }
+    
+    /**
+     * 提交更改，将SqlData对象的数据更新到数据库中
+     * @param noteId 笔记的ID
+     * @param validateVersion 是否需要验证版本号
+     * @param version 版本号
+     */
+    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;
+    }
+    
+    /**
+     * 获取数据库记录的ID
+     * @return 数据库记录的ID
+     */
+    public long getId() {
+        return mDataId;
+    }
+}
diff --git a/SqlNote.java b/SqlNote.java
new file mode 100644
index 0000000..e48eea0
--- /dev/null
+++ b/SqlNote.java
@@ -0,0 +1,94 @@
+// The class Note is used to handle note-related data and operations, including the creation, updating, and querying of notes.
+public class Note {
+    // Other member variables and constructors are omitted here.
+
+    /**
+     * Update the content of the note.
+     * @param data The new content of the note.
+     * @return Returns true if the update is successful, otherwise returns false.
+     */
+    public boolean setContent(String data) {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Get the content of the note in the form of a JSONObject.
+     * @return Returns the JSONObject containing the note content, or null if the operation fails.
+     */
+    public JSONObject getContent() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Set the parent ID of the note.
+     * @param id The new parent ID of the note.
+     */
+    public void setParentId(long id) {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Set the GTASK ID of the note.
+     * @param gid The new GTASK ID of the note.
+     */
+    public void setGtaskId(String gid) {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Set the sync ID of the note.
+     * @param syncId The new sync ID of the note.
+     */
+    public void setSyncId(long syncId) {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Reset the local modification flag of the note.
+     */
+    public void resetLocalModified() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Get the ID of the note.
+     * @return Returns the ID of the note.
+     */
+    public long getId() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Get the parent ID of the note.
+     * @return Returns the parent ID of the note.
+     */
+    public long getParentId() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Get the snippet of the note.
+     * @return Returns the snippet of the note.
+     */
+    public String getSnippet() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Check if the note type is a regular note.
+     * @return Returns true if the note type is a regular note, otherwise returns false.
+     */
+    public boolean isNoteType() {
+        // Existing code is omitted here.
+    }
+
+    /**
+     * Commit the changes of the note.
+     * @param validateVersion Whether to validate the version before updating.
+     * @throws ActionFailureException If the note creation fails.
+     * @throws IllegalStateException If the note ID is invalid or the update fails.
+     */
+    public void commit(boolean validateVersion) {
+        // Existing code is omitted here.
+    }
+}
diff --git a/Task.java b/Task.java
new file mode 100644
index 0000000..c66b077
--- /dev/null
+++ b/Task.java
@@ -0,0 +1,392 @@
+```java
+// Task类继承自Node类，用于表示一个任务对象
+public class Task extends Node {
+    // 日志标签，用于标识日志信息来源
+    private static final String TAG = Task.class.getSimpleName();
+
+    // 表示任务是否已完成
+    private boolean mCompleted;
+
+    // 任务的备注信息
+    private String mNotes;
+
+    // 任务的元信息，使用JSONObject存储
+    private JSONObject mMetaInfo;
+
+    // 任务的前一个兄弟任务，用于任务排序
+    private Task mPriorSibling;
+
+    // 任务所属的任务列表
+    private TaskList mParent;
+
+    // Task类的构造方法，初始化任务的默认状态
+    public Task() {
+        super();
+        mCompleted = false;
+        mNotes = null;
+        mPriorSibling = null;
+        mParent = null;
+        mMetaInfo = null;
+    }
+
+    /**
+     * 生成任务创建操作的JSON对象
+     * @param actionId 操作ID
+     * @return 返回表示创建操作的JSONObject
+     * @throws ActionFailureException 如果JSON对象生成失败，则抛出此异常
+     */
+    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;
+    }
+
+    /**
+     * 生成任务更新操作的JSON对象
+     * @param actionId 操作ID
+     * @return 返回表示更新操作的JSONObject
+     * @throws ActionFailureException 如果JSON对象生成失败，则抛出此异常
+     */
+    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;
+    }
+
+    /**
+     * 通过远程JSON对象设置任务内容
+     * @param js 远程JSON对象，包含任务的相关信息
+     * @throws ActionFailureException 如果设置内容失败，则抛出此异常
+     */
+    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");
+            }
+        }
+    }
+
+    /**
+     * 通过本地JSON对象设置任务内容
+     * @param js 本地JSON对象，包含任务的相关信息
+     * @throws ActionFailureException 如果设置内容失败，则抛出此异常
+     */
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)
+                || !js.has(GTaskStringUtils.META_HEAD_DATA)) {
+```
+
+// 当没有可用内容时记录警告信息
+Log.w(TAG, "setContentByLocalJSON: nothing is avaiable");
+}
+
+try {
+    // 从JSON对象中获取笔记和数据数组
+    JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+    JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+    // 检查笔记类型是否无效
+    if (note.getInt(NoteColumns.TYPE) != Notes.TYPE_NOTE) {
+        Log.e(TAG, "invalid type");
+        return;
+    }
+
+    // 遍历数据数组以查找并设置笔记内容
+    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) {
+    // 记录并打印JSONException的堆栈跟踪
+    Log.e(TAG, e.toString());
+    e.printStackTrace();
+}
+```
+```java
+/**
+ * 从内容生成本地使用的JSON对象
+ * 
+ * @return 表示笔记内容的JSONObject，如果内容为空则返回null
+ */
+public JSONObject getLocalJSONFromContent() {
+    String name = getName();
+    try {
+        // 处理从网页创建的新任务
+        if (mMetaInfo == null) {
+            if (name == null) {
+                Log.w(TAG, "the note seems to be an empty one");
+                return null;
+            }
+
+            // 构建新的笔记JSON对象
+            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 {
+            // 处理已同步的任务
+            JSONObject note = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            JSONArray dataArray = mMetaInfo.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+            // 更新数据数组中的笔记内容
+            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) {
+        // 记录并打印JSONException的堆栈跟踪
+        Log.e(TAG, e.toString());
+        e.printStackTrace();
+        return null;
+    }
+}
+```
+```java
+/**
+ * 设置任务的元信息
+ * 
+ * @param metaData 包含笔记信息的MetaData对象
+ */
+public void setMetaInfo(MetaData metaData) {
+    if (metaData != null && metaData.getNotes() != null) {
+        try {
+            // 将笔记信息转换为JSON对象
+            mMetaInfo = new JSONObject(metaData.getNotes());
+        } catch (JSONException e) {
+            // 转换失败时记录错误并将mMetaInfo设置为null
+            Log.w(TAG, e.toString());
+            mMetaInfo = null;
+        }
+    }
+}
+```
+```java
+/**
+ * 根据当前状态和数据库游标确定同步操作
+ * 
+ * @param c 指向数据库中笔记数据的游标
+ * @return 表示要执行的同步操作的整数
+ */
+public int getSyncAction(Cursor c) {
+    try {
+        // 从mMetaInfo中获取笔记信息
+        JSONObject noteInfo = null;
+        if (mMetaInfo != null && mMetaInfo.has(GTaskStringUtils.META_HEAD_NOTE)) {
+            noteInfo = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+        }
+
+        // 根据笔记信息确定同步操作
+        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;
+        }
+
+        // 验证笔记ID
+        if (c.getLong(SqlNote.ID_COLUMN) != noteInfo.getLong(NoteColumns.ID)) {
+            Log.w(TAG, "note id doesn't match");
+            return SYNC_ACTION_UPDATE_LOCAL;
+        }
+
+        // 根据本地修改状态确定同步操作
+        if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+            if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                return SYNC_ACTION_NONE;
+            } else {
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+        } else {
+            // 验证GTasks 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()) {
+                return SYNC_ACTION_UPDATE_REMOTE;
+            } else {
+                return SYNC_ACTION_UPDATE_CONFLICT;
+            }
+        }
+    } catch (Exception e) {
+        // 记录并打印异常的堆栈跟踪
+        Log.e(TAG, e.toString());
+        e.printStackTrace();
+    }
+
+    return SYNC_ACTION_ERROR;
+}
+```
+```java
+/**
+ * 检查任务是否有值得保存的内容
+ * 
+ * @return 布尔值，表示任务是否有值得保存的内容
+ */
+public boolean isWorthSaving() {
+    return mMetaInfo != null || (getName() != null && getName().trim().length() > 0)
+            || (getNotes() != null && getNotes().trim().length() > 0);
+}
+```
+```java
+// 设置任务的完成状态
+public void setCompleted(boolean completed) {
+    this.mCompleted = completed;
+}
+
+// 设置任务的笔记内容
+public void setNotes(String notes) {
+    this.mNotes = notes;
+}
+
+// 设置任务的前一个兄弟任务
+public void setPriorSibling(Task priorSibling) {
+    this.mPriorSibling = priorSibling;
+}
+
+// 设置任务的父任务列表
+public void setParent(TaskList parent) {
+    this.mParent = parent;
+}
+
+// 获取任务的完成状态
+public boolean getCompleted() {
+    return this.mCompleted;
+}
+
+// 获取任务的笔记内容
+public String getNotes() {
+    return this.mNotes;
+}
+
+// 获取任务的前一个兄弟任务
+public Task getPriorSibling() {
+    return this.mPriorSibling;
+}
+
+// 获取任务的父任务列表
+public TaskList getParent() {
+    return this.mParent;
+}
+```
diff --git a/TaskList.java b/TaskList.java
new file mode 100644
index 0000000..bd71738
--- /dev/null
+++ b/TaskList.java
@@ -0,0 +1,449 @@
+```java
+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;
+
+/**
+ * TaskList 类代表一个任务列表，继承自 Node 类
+ * 它包含一个任务列表和相关的操作，如创建和更新任务列表的 JSON 对象
+ */
+public class TaskList extends Node {
+    private static final String TAG = TaskList.class.getSimpleName();
+
+    // 任务列表的索引
+    private int mIndex;
+
+    // 任务列表
+    private ArrayList<Task> mChildren;
+
+    /**
+     * TaskList 构造函数初始化任务列表和索引
+     */
+    public TaskList() {
+        super();
+        mChildren = new ArrayList<Task>();
+        mIndex = 1;
+    }
+
+    /**
+     * 生成创建任务列表的 JSON 对象
+     * 
+     * @param actionId 操作的 ID
+     * @return 创建操作的 JSON 对象
+     * @throws ActionFailureException 如果生成 JSON 对象失败
+     */
+    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;
+    }
+
+    /**
+     * 生成更新任务列表的 JSON 对象
+     * 
+     * @param actionId 操作的 ID
+     * @return 更新操作的 JSON 对象
+     * @throws ActionFailureException 如果生成 JSON 对象失败
+     */
+    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;
+    }
+
+    /**
+     * 通过远程 JSON 对象设置任务列表的内容
+     * 
+     * @param js 远程 JSON 对象
+     * @throws ActionFailureException 如果设置内容失败
+     */
+    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");
+            }
+        }
+    }
+
+    /**
+     * 通过本地 JSON 对象设置任务列表的内容
+     * 
+     * @param js 本地 JSON 对象
+     * @throws ActionFailureException 如果设置内容失败
+     */
+    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();
+}
+}
+
+/**
+ * 获取本地 JSON 内容
+ * 
+ * 该方法构建一个表示本地笔记信息的 JSONObject，包括文件夹名称和类型
+ * @return 包含本地笔记信息的 JSONObject，如果发生异常则返回 null
+ */
+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;
+    }
+}
+
+/**
+ * 根据游标获取同步操作
+ * 
+ * 根据游标信息确定本地和远程笔记之间的同步操作
+ * @param c 指向数据库记录的游标
+ * @return 同步操作常量之一
+ */
+public int getSyncAction(Cursor c) {
+    try {
+        if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+            // 本地没有更新
+            if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                // 双方都没有更新
+                return SYNC_ACTION_NONE;
+            } else {
+                // 将远程应用到本地
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+        } else {
+            // 验证 gtask id
+            if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                Log.e(TAG, "gtask id 不匹配");
+                return SYNC_ACTION_ERROR;
+            }
+            if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                // 仅本地有修改
+                return SYNC_ACTION_UPDATE_REMOTE;
+            } else {
+                // 对于文件夹冲突，仅应用本地修改
+                return SYNC_ACTION_UPDATE_REMOTE;
+            }
+        }
+    } catch (Exception e) {
+        Log.e(TAG, e.toString());
+        e.printStackTrace();
+    }
+
+    return SYNC_ACTION_ERROR;
+}
+
+/**
+ * 获取子任务的数量
+ * 
+ * @return 子任务的数量
+ */
+public int getChildTaskCount() {
+    return mChildren.size();
+}
+
+/**
+ * 添加子任务
+ * 
+ * 如果子任务列表中不存在该任务，则将其添加到子任务列表中
+ * @param task 要添加的任务
+ * @return 如果任务成功添加则返回 true，否则返回 false
+ */
+public boolean addChildTask(Task task) {
+    boolean ret = false;
+    if (task != null && !mChildren.contains(task)) {
+        ret = mChildren.add(task);
+        if (ret) {
+            // 需要设置前一个兄弟任务和父任务
+            task.setPriorSibling(mChildren.isEmpty() ? null : mChildren
+                    .get(mChildren.size() - 1));
+            task.setParent(this);
+        }
+    }
+    return ret;
+}
+
+/**
+ * 在指定索引位置添加子任务
+ * 
+ * 将任务添加到子任务列表的指定索引位置，并更新任务列表
+ * @param task 要添加的任务
+ * @param index 要添加任务的索引位置
+ * @return 如果任务成功添加则返回 true，否则返回 false
+ */
+public boolean addChildTask(Task task, int index) {
+    if (index < 0 || index > mChildren.size()) {
+        Log.e(TAG, "添加子任务: 无效的索引");
+        return false;
+    }
+
+    int pos = mChildren.indexOf(task);
+    if (task != null && pos == -1) {
+        mChildren.add(index, task);
+
+        // 更新任务列表
+        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;
+}
+
+/**
+ * 移除子任务
+ * 
+ * 从子任务列表中移除任务，并更新任务列表
+ * @param task 要移除的任务
+ * @return 如果任务成功移除则返回 true，否则返回 false
+ */
+public boolean removeChildTask(Task task) {
+    boolean ret = false;
+    int index = mChildren.indexOf(task);
+    if (index != -1) {
+        ret = mChildren.remove(task);
+
+        if (ret) {
+            // 重置前一个兄弟任务和父任务
+            task.setPriorSibling(null);
+            task.setParent(null);
+
+            // 更新任务列表
+            if (index != mChildren.size()) {
+                mChildren.get(index).setPriorSibling(
+                        index == 0 ? null : mChildren.get(index - 1));
+            }
+        }
+    }
+    return ret;
+}
+
+/**
+ * 移动子任务到新的索引位置
+ * 
+ * 将任务在子任务列表中移动到新的索引位置
+ * @param task 要移动的任务
+ * @param index 新的索引位置
+ * @return 如果任务成功移动则返回 true，否则返回 false
+ */
+public boolean moveChildTask(Task task, int index) {
+    if (index < 0 || index >= mChildren.size()) {
+        Log.e(TAG, "移动子任务: 无效的索引");
+        return false;
+    }
+
+    int pos = mChildren.indexOf(task);
+    if (pos == -1) {
+        Log.e(TAG, "移动子任务: 任务不在列表中");
+        return false;
+    }
+
+    if (pos == index)
+        return true;
+    return (removeChildTask(task) && addChildTask(task, index));
+}
+
+/**
+ * 通过 GID 查找子任务
+ * 
+ * @param gid 要查找的任务的 GID
+ * @return 找到的任务，如果没有找到则返回 null
+ */
+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;
+}
+
+/**
+ * 获取子任务的索引
+ * 
+ * @param task 子任务
+ * @return 子任务的索引，如果没有找到则返回 -1
+ */
+public int getChildTaskIndex(Task task) {
+    return mChildren.indexOf(task);
+}
+
+/**
+ * 通过索引获取子任务
+ * 
+ * @param index 子任务的索引
+ * @return 指定索引位置的子任务，如果索引无效则返回 null
+ */
+public Task getChildTaskByIndex(int index) {
+    if (index < 0 || index >= mChildren.size()) {
+        Log.e(TAG, "通过索引获取任务: 无效的索引");
+        return null;
+    }
+    return mChildren.get(index);
+}
+
+/**
+ * 通过 GID 查找子任务（替代方法）
+ * 
+ * @param gid 要查找的任务的 GID
+ * @return 找到的任务，如果没有找到则返回 null
+ */
+public Task getChilTaskByGid(String gid) {
+    for (Task task : mChildren) {
+        if (task.getGid().equals(gid))
+            return task;
+    }
+    return null;
+}
+
+/**
+ * 获取子任务列表
+ * 
+ * @return 子任务列表
+ */
+public ArrayList<Task> getChildTaskList() {
+    return this.mChildren;
+}
+
+/**
+ * 设置任务的索引
+ * 
+ * @param index 任务的新索引
+ */
+public void setIndex(int index) {
+    this.mIndex = index;
+}
+
+/**
+ * 获取任务的索引
+ * 
+ * @return 任务的索引
+ */
+public int getIndex() {
+    return this.mIndex;
+}
+}
+```