diff --git a/data/Notes.java b/data/Notes.java
new file mode 100644
index 0000000..eb6d354
--- /dev/null
+++ b/data/Notes.java
@@ -0,0 +1,322 @@
+/*
+ * 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，定义了与笔记应用相关的常量和数据结构。
+ */
+public class Notes {
+
+    // 内容提供者（Content Provider）的权威名称
+    public static final String AUTHORITY = "micode_notes";
+
+    // 日志标签，用于在日志输出中标识来自此类的消息
+    public static final String TAG = "Notes";
+
+    // 定义笔记类型的常量
+    public static final int TYPE_NOTE = 0; // 普通笔记类型
+    public static final int TYPE_FOLDER = 1; // 文件夹类型
+    public static final int TYPE_SYSTEM = 2; // 系统类型（可能用于特殊的系统笔记或文件夹）
+
+    /**
+     * 以下ID是系统文件夹的标识符。
+     * 这些常量用于在数据库中唯一标识特定的系统文件夹。
+     */
+    public static final int ID_ROOT_FOLDER = 0; // 根文件夹的ID，通常是默认的文件夹
+    public static final int ID_TEMPARAY_FOLDER = -1; // 临时文件夹的ID，用于存放不属于任何文件夹的笔记
+    public static final int ID_CALL_RECORD_FOLDER = -2; // 通话记录文件夹的ID，用于存储通话记录相关的笔记
+    public static final int ID_TRASH_FOLER = -3; // 垃圾文件夹的ID，可能用于存放被删除的笔记
+
+    // 注意：此类可能还需要其他方法和属性来支持笔记应用的功能，
+    // 例如，可能包含用于构建URI、查询数据库等的方法。
+    // 但根据当前提供的代码，以上是对现有代码的详细注释。
+}
+// 定义一系列用于Intent传递的额外数据的键名
+public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date"; // 用于传递提醒日期的键名
+public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id"; // 用于传递背景颜色ID的键名
+public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id"; // 用于传递小部件ID的键名
+public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type"; // 用于传递小部件类型的键名
+public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id"; // 用于传递文件夹ID的键名
+public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date"; // 用于传递通话日期的键名
+
+// 定义小部件类型的常量
+public static final int TYPE_WIDGET_INVALIDE = -1; // 无效的小部件类型
+public static final int TYPE_WIDGET_2X = 0; // 2x2大小的小部件类型
+public static final int TYPE_WIDGET_4X = 1; // 4x4大小的小部件类型
+
+// 定义一个内部类来组织数据相关的常量
+public static class DataConstants {
+    // 笔记和通话记录的内容类型（MIME类型）
+    public static final String NOTE = TextNote.CONTENT_ITEM_TYPE; // 普通笔记的内容类型
+    public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE; // 通话记录笔记的内容类型
+    
+    // 注意：TextNote和CallNote应该是定义了CONTENT_ITEM_TYPE常量的类，
+    // 这些常量通常用于内容提供者（Content Provider）中，以标识不同的数据类型。
+}
+
+// 此处应定义一个Uri类型的常量，但由于原始代码未给出具体Uri，所以此处仅为说明性注释。
+// public static final Uri CONTENT_URI_ALL_NOTES_AND_FOLDERS = Uri.parse("content://micode_notes/notes_and_folders");
+
+    /**
+     * Uri to query all notes and folders
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * Uri to query data
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id";
+
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";
+    }
+
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA5 = "data5";
+    }
+// 定义一个静态内部类TextNote，它实现了DataColumns接口（假设DataColumns接口定义了一些与数据列相关的常量或方法）
+public static final class TextNote implements DataColumns {
+    
+    /**
+     * 用于指示文本是否处于检查列表模式的字段名。
+     * <P>类型：整数。1表示检查列表模式，0表示普通模式。</P>
+     * 这个字段在数据库中用于存储笔记的显示模式，
+     * 检查列表模式可能意味着笔记以带有复选框的列表形式显示，
+     * 而普通模式则是普通的文本笔记。
+     */
+    public static final String MODE = DATA1; // 假设DATA1是在DataColumns接口中定义的某个常量，表示数据库中的一列
+
+    // 检查列表模式的常量值
+    public static final int MODE_CHECK_LIST = 1; // 表示检查列表模式
+    // （可以隐含地，MODE_NORMAL = 0，表示普通模式，虽然没有显式定义）
+
+    /**
+     * 文本笔记的内容类型（MIME类型），用于表示一组文本笔记的集合。
+     * 这个类型通常用于内容提供者（Content Provider）中，
+     * 以标识可以返回多个文本笔记的查询结果。
+     */
+    public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+    /**
+     * 文本笔记的单个项的内容类型（MIME类型），用于表示一个具体的文本笔记。
+     * 这个类型也用于内容提供者中，但它是用来标识单个文本笔记的。
+     */
+    public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+    /**
+     * 文本笔记的内容URI，用于通过内容提供者访问文本笔记数据。
+     * 这个URI是构建在应用的内容提供者权威名称（AUTHORITY）之上的，
+     * 并且指向文本笔记的数据表（或集合）。
+     */
+    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    // 注意：AUTHORITY应该是一个在应用的某个地方定义的常量，表示内容提供者的权威名称。
+}
+
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3;
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }
+}
diff --git a/data/NotesDatabaseHelper.java b/data/NotesDatabaseHelper.java
new file mode 100644
index 0000000..6ecc224
--- /dev/null
+++ b/data/NotesDatabaseHelper.java
@@ -0,0 +1,336 @@
+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;
+
+// 继承自SQLiteOpenHelper，用于管理笔记数据库的创建和升级
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // 数据库名称
+    private static final String DB_NAME = "note.db";
+    // 数据库版本号
+    private static final int DB_VERSION = 4;
+
+    // 定义表名接口
+    public interface TABLE {
+        public static final String NOTE = "note";
+        public static final String DATA = "data";
+    }
+
+    private static final String TAG = "NotesDatabaseHelper";
+    // 单例模式，确保只有一个实例
+    private static NotesDatabaseHelper mInstance;
+
+    // 创建note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data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 ''" +
+                    ")";
+
+    // 创建note_id索引的SQL语句
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+            "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+                    TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    // 当将笔记移动到文件夹时增加文件夹的笔记数量的触发器
+    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";
+
+    // 当从文件夹中移动笔记时减少文件夹的笔记数量的触发器
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+            "CREATE TRIGGER decrease_folder_count_on_update " +
+                    " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+                    "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+                    "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+                    " END";
+
+    // 当向文件夹中插入新笔记时增加文件夹的笔记数量的触发器
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+            "CREATE TRIGGER increase_folder_count_on_insert " +
+                    " AFTER INSERT ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+                    "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+                    " END";
+
+    // 当从文件夹中删除笔记时减少文件夹的笔记数量的触发器
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER decrease_folder_count_on_delete " +
+                    " AFTER DELETE ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+                    "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+                    "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+                    " END";
+
+    // 当插入类型为{@link DataConstants#NOTE}的数据时更新笔记内容的触发器
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_insert " +
+                    " AFTER INSERT ON " + TABLE.DATA +
+                    " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+                    "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+                    " END";
+
+    // 当类型为{@link DataConstants#NOTE}的数据更新时更新笔记内容的触发器
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_update " +
+                    " AFTER UPDATE ON " + TABLE.DATA +
+                    " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+                    "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+                    " END";
+
+    // 当类型为{@link DataConstants#NOTE}的数据删除时更新笔记内容的触发器
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_delete " +
+                    " AFTER delete ON " + TABLE.DATA +
+                    " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.SNIPPET + "=''" +
+                    "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+                    " END";
+
+    // 当笔记被删除时删除属于该笔记的数据的触发器
+    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER delete_data_on_delete " +
+                    " AFTER DELETE ON " + TABLE.NOTE +
+                    " BEGIN" +
+                    "  DELETE FROM " + TABLE.DATA +
+                    "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
+                    " END";
+
+    // 当文件夹被删除时删除属于该文件夹的笔记的触发器
+    private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER folder_delete_notes_on_delete " +
+                    " AFTER DELETE ON " + TABLE.NOTE +
+                    " BEGIN" +
+                    "  DELETE FROM " + TABLE.NOTE +
+                    "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+                    " END";
+
+    // 当文件夹被移动到回收站文件夹时移动属于该文件夹的笔记的触发器
+    private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
+            "CREATE TRIGGER folder_move_notes_on_trash " +
+                    " AFTER UPDATE ON " + TABLE.NOTE +
+                    " WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+                    "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+                    " END";
+
+    // 私有构造函数，防止外部实例化
+    private NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+    // 创建note表
+    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note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（通话记录文件夹、根文件夹、临时文件夹、回收站文件夹）
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+        // 通话记录文件夹
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // 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);
+
+        // 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);
+
+        // 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data表
+    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data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);
+    }
+
+    // 获取单例实例
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }
+
+    // 数据库首次创建时调用
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createNoteTable(db);
+        createDataTable(db);
+    }
+
+    // 数据库升级时调用
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        // 从版本1升级到版本2
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // 此次升级包括从v2到v3的升级
+            oldVersion++;
+        }
+
+        // 从版本2升级到版本3（如果未跳过）
+        if (oldVersion == 2 &&!skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+
+        // 从版本3升级到版本4
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+
+        // 如果需要重新创建触发器
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+
+        // 如果版本升级失败
+        if (oldVersion!= newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }
+
+    // 从版本1升级到版本2的具体操作（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);
+    }
+
+    // 从版本2升级到版本3的具体操作（删除未使用的触发器，添加gtask_id列，添加回收站文件夹）
+    private void upgradeToV3(SQLiteDatabase db) {
+        // 删除未使用的触发器
+        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");
+
+        // 添加gtask_id列
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+
+        // 添加回收站系统文件夹
+        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);
+    }
+
+    // 从版本3升级到版本4的具体操作（添加version列）
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + Note
\ No newline at end of file
diff --git a/data/NotesProvider.java b/data/NotesProvider.java
new file mode 100644
index 0000000..9f2400b
--- /dev/null
+++ b/data/NotesProvider.java
@@ -0,0 +1,319 @@
+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;
+
+// 继承自ContentProvider，用于提供对笔记数据的访问接口
+public class NotesProvider extends ContentProvider {
+    // UriMatcher用于匹配传入的Uri，确定操作类型
+    private static final UriMatcher mMatcher;
+    // 数据库帮助类实例
+    private NotesDatabaseHelper mHelper;
+    private static final String TAG = "NotesProvider";
+
+    // 定义不同Uri的匹配码
+    private static final int URI_NOTE = 1;
+    private static final int URI_NOTE_ITEM = 2;
+    private static final int URI_DATA = 3;
+    private static final int URI_DATA_ITEM = 4;
+    private static final int URI_SEARCH = 5;
+    private static final int URI_SEARCH_SUGGEST = 6;
+
+    static {
+        // 初始化UriMatcher
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        // 添加note表的Uri匹配规则
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
+        // 添加data表的Uri匹配规则
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
+        // 添加搜索相关的Uri匹配规则
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
+    }
+
+    // 用于搜索结果的投影，包括笔记的ID、标题、内容等信息
+    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;
+
+    // 用于搜索笔记片段的查询语句
+    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;
+
+    // 初始化方法，获取数据库帮助类实例
+    @Override
+    public boolean onCreate() {
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }
+
+    // 查询数据的方法，根据Uri执行相应的查询操作并返回Cursor
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+                        String sortOrder) {
+        Cursor c = null;
+        // 获取可读数据库实例
+        SQLiteDatabase db = mHelper.getReadableDatabase();
+        String id = null;
+
+        // 根据Uri匹配码执行不同的查询操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 查询note表
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                // 查询单个note项
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                // 查询data表
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                // 查询单个data项
+                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:
+                // 搜索相关操作
+                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);
+        }
+
+        // 设置通知Uri，以便数据变化时通知观察者
+        if (c!= null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        return c;
+    }
+
+    // 插入数据的方法，根据Uri将数据插入到相应的表中
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        // 获取可写数据库实例
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        long dataId = 0, noteId = 0, insertedId = 0;
+
+        // 根据Uri匹配码执行不同的插入操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 插入note表
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+            case URI_DATA:
+                // 插入data表
+                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note表的Uri数据变化
+        if (noteId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
+        }
+        // 通知data表的Uri数据变化
+        if (dataId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
+        }
+        return ContentUris.withAppendedId(uri, insertedId);
+    }
+
+    // 删除数据的方法，根据Uri从相应的表中删除数据
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        int count = 0;
+        String id = null;
+        // 获取可写数据库实例
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean deleteData = false;
+
+        // 根据Uri匹配码执行不同的删除操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 删除note表中的数据
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                // 删除单个note项
+                id = uri.getPathSegments().get(1);
+                long noteId = Long.valueOf(id);
+                if (noteId <= 0) {
+                    break;
+                }
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                // 删除data表中的数据
+                count = db.delete(TABLE.DATA, selection, selectionArgs);
+                deleteData = true;
+                break;
+            case URI_DATA_ITEM:
+                // 删除单个data项
+                id = uri.getPathSegments().get(1);
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                deleteData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+
+        // 如果删除了数据，通知相关Uri的数据变化
+        if (count > 0) {
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+
+    // 更新数据的方法，根据Uri更新相应表中的数据
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        int count = 0;
+        String id = null;
+        // 获取可写数据库实例
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean updateData = false;
+
+        // 根据Uri匹配码执行不同的更新操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 更新note表中的数据
+                increaseNoteVersion(-1, selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                // 更新单个note项
+                id = uri.getPathSegments().get(1);
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                // 更新data表中的数据
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);
+                updateData = true;
+                break;
+            case URI_DATA_ITEM:
+                // 更新单个data项
+                id = uri.getPathSegments().get(1);
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                updateData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+
+        // 如果更新了数据，通知相关Uri的数据变化
+        if (count > 0) {
+            if (updateData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+
+    // 辅助方法，用于解析查询条件
+    private String parseSelection(String selection) {
+        return (!TextUtils.isEmpty(selection)? " AND (" + selection + ')' : "");
+    }
+
+    // 增加笔记版本号的方法
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+        StringBuilder sql = new StringBuilder(120);
+        sql.append("UPDATE ");
+        sql.append(TABLE.NOTE);
+        sql.append(" SET ");
+        sql.append(NoteColumns.VERSION);
+        sql.append("=" + NoteColumns.VERSION + "+1 ");
+        if (id > 0 ||!TextUtils.isEmpty(selection)) {
+            sql.append(" WHERE ");
+        }
+        if (id > 0) {
+            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
+        }
+        if (!TextUtils.isEmpty(selection)) {
+            String selectString = id > 0? parseSelection(selection) : selection;
+            for (String args : selectionArgs) {
+                selectString = selectString.replaceFirst("\\?", args);
+            }
+            sql.append(selectString);
+        }
+        mHelper.getWritableDatabase().execSQL(sql.toString());
+    }
+
+    // 获取数据类型的方法（未实现）
+    @Override
+    public String getType(Uri uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+}
\ No newline at end of file