commit 6229f17b85c1ce536befcd832ecbc8bfbea70443
Author: jmh <2631499212@qq.com>
Date:   Mon May 19 18:52:21 2025 +0800

    jmh

diff --git a/doc/小米便签开源代码的泛读报告.docx b/doc/小米便签开源代码的泛读报告.docx
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diff --git a/doc/运行结果.doc b/doc/运行结果.doc
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diff --git a/src/data/Contact.java b/src/data/Contact.java
new file mode 100644
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--- /dev/null
+++ b/src/data/Contact.java
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+
+
+java
+Copy Code
+package net.micode.notes.data;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.provider.ContactsContract.CommonDataKinds.Phone;
+import android.provider.ContactsContract.Data;
+import android.telephony.PhoneNumberUtils;
+import android.util.Log;
+
+import java.util.HashMap;
+
+/*
+ * 联系人查询工具类
+ * 提供根据电话号码获取联系人姓名的功能
+ */
+public class Contact {
+    // 缓存联系人信息的HashMap，key为电话号码，value为联系人姓名
+    private static HashMap<String, String> sContactCache;
+    // 日志标签
+    private static final String TAG = "Contact";
+
+    /*
+     * 联系人查询SQL条件语句模板
+     * 包含以下条件：
+     * 1. 电话号码匹配条件(PHONE_NUMBERS_EQUAL)
+     * 2. MIME类型为电话类型
+     * 3. RAW_CONTACT_ID在phone_lookup表中
+     * 其中'+'为占位符，后续会被替换为最小匹配位数
+     */
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
+    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+    + " AND " + Data.RAW_CONTACT_ID + " IN "
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+
+    /**
+     * 根据电话号码获取联系人姓名
+     * @param context 上下文对象
+     * @param phoneNumber 要查询的电话号码
+     * @return 联系人姓名，未找到则返回null
+     */
+    public static String getContact(Context context, String phoneNumber) {
+        // 初始化缓存
+        if(sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+
+        // 先检查缓存中是否存在
+        if(sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 构建完整查询条件：替换最小匹配位数占位符
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        
+        // 查询联系人数据库
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,                  // 数据URI
+                new String [] { Phone.DISPLAY_NAME }, // 查询列
+                selection,                         // 查询条件
+                new String[] { phoneNumber },      // 查询参数
+                null);                             // 排序方式
+
+        // 处理查询结果
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                // 获取第一条记录的姓名
+                String name = cursor.getString(0);
+                // 存入缓存
+                sContactCache.put(phoneNumber, name);
+                return name;
+            } catch (IndexOutOfBoundsException e) {
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                cursor.close();  // 确保关闭Cursor
+            }
+        } else {
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}
+
+
diff --git a/src/data/Notes.java b/src/data/Notes.java
new file mode 100644
index 0000000..916f21c
--- /dev/null
+++ b/src/data/Notes.java
@@ -0,0 +1,281 @@
+package net.micode.notes.data;
+
+import android.net.Uri;
+
+/**
+ * 该类为笔记内容提供者定义了常量，包括：
+ * - 笔记类型和文件夹ID
+ * - Intent额外数据和小部件类型
+ * - 笔记和数据的数据库列定义
+ */
+public class Notes {
+    // 内容提供者权限，用于唯一标识内容提供者
+    public static final String AUTHORITY = "micode_notes";
+    // 日志标签，用于调试输出
+    public static final String TAG = "Notes";
+    
+    // 笔记类型常量
+    public static final int TYPE_NOTE     = 0;   // 普通笔记
+    public static final int TYPE_FOLDER   = 1;   // 文件夹
+    public static final int TYPE_SYSTEM   = 2;   // 系统文件夹
+
+    // 特殊文件夹ID
+    public static final int ID_ROOT_FOLDER = 0;           // 根文件夹ID
+    public static final int ID_TEMPARAY_FOLDER = -1;      // 临时文件夹ID
+    public static final int ID_CALL_RECORD_FOLDER = -2;   // 通话记录文件夹ID
+    public static final int ID_TRASH_FOLER = -3;          // 回收站文件夹ID
+
+    // Intent额外数据键名，用于在Activity之间传递数据
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date";
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date";
+
+    // 小部件类型常量
+    public static final int TYPE_WIDGET_INVALIDE      = -1;  // 无效小部件
+    public static final int TYPE_WIDGET_2X            = 0;   // 2x尺寸小部件
+    public static final int TYPE_WIDGET_4X            = 1;   // 4x尺寸小部件
+
+    /**
+     * 包含数据类型的常量
+     */
+    public static class DataConstants {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;      // 文本笔记MIME类型
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE; // 通话笔记MIME类型
+    }
+
+    /**
+     * 用于查询所有笔记和文件夹的Uri
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * 用于查询数据项的Uri
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    /**
+     * 'note'表的列定义
+     */
+    public interface NoteColumns {
+        /**
+         * 行的唯一ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * 笔记或文件夹的父级ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * 笔记或文件夹的创建日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * 最新修改日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * 提醒/闹钟日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * 文件夹名称或笔记的文本内容(预览/摘要)
+         * <P> 类型: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * 笔记的小部件ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * 笔记的小部件类型
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * 笔记的背景颜色ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id";
+
+        /**
+         * 标志指示笔记是否有附件
+         * 对于文本笔记，没有附件；对于多媒体笔记，至少有一个附件
+         * <P> 类型: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * 文件夹中笔记的数量(仅对文件夹相关)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * 项目类型：文件夹或笔记
+         * <P> 类型: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * 最后同步ID(用于同步目的)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";
+
+        /**
+         * 标志指示是否本地修改
+         * <P> 类型: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * 移动到临时文件夹之前的原始父级ID
+         * <P> 类型 : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * Google任务ID(用于Google任务集成)
+         * <P> 类型 : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * 版本代码(用于数据版本控制)
+         * <P> 类型 : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";
+    }
+
+    /**
+     * 'data'表的列定义(包含笔记内容和元数据)
+     */
+    public interface DataColumns {
+        /**
+         * 行的唯一ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * 此行表示的项目的MIME类型
+         * <P> 类型: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * 此数据所属笔记的引用ID
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * 数据项的创建日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * 最新修改日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * 数据内容(实际笔记内容)
+         * <P> 类型: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+        /**
+         * 通用数据列，含义由{@link #MIME_TYPE}指定，用于整数数据类型
+         * <P> 类型: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * 通用数据列，含义由{@link #MIME_TYPE}指定，用于整数数据类型
+         * <P> 类型: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * 通用数据列，含义由{@link #MIME_TYPE}指定，用于文本数据类型
+         * <P> 类型: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * 通用数据列，含义由{@link #MIME_TYPE}指定，用于文本数据类型
+         * <P> 类型: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * 通用数据列，含义由{@link #MIME_TYPE}指定，用于文本数据类型
+         * <P> 类型: TEXT </P>
+         */
+        public static final String DATA5 = "data5";
+    }
+
+    /**
+     * 文本笔记特定的常量
+     */
+    public static final class TextNote implements DataColumns {
+        /**
+         * 模式指示文本是否处于复选框列表模式
+         * <P> 类型: Integer 1:复选框列表模式 0:普通模式 </P>
+         */
+        public static final String MODE = DATA1;
+
+        public static final int MODE_CHECK_LIST = 1;  // 复选框列表模式
+
+        // 文本笔记的MIME类型
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        // 文本笔记的内容URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }
+
+    /**
+     * 通话笔记特定的常量
+     */
+    public static final class CallNote implements DataColumns {
+        /**
+         * 此记录的通话日期(时间戳)
+         * <P> 类型: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * 此记录的电话号码
+         * <P> 类型: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3;
+
+        // 通话笔记的MIME类型
+        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";
+
+        // 通话笔记的内容URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }
+}
\ No newline at end of file
diff --git a/src/data/NotesDatabaseHelper.java b/src/data/NotesDatabaseHelper.java
new file mode 100644
index 0000000..77cb87f
--- /dev/null
+++ b/src/data/NotesDatabaseHelper.java
@@ -0,0 +1,409 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
+
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+
+/**
+ * Database helper class for managing the notes database creation and version management.
+ * This class handles:
+ * - Database creation (tables, indexes, triggers)
+ * - Database version upgrades
+ * - System folder initialization
+ */
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // Database name and version constants
+    private static final String DB_NAME = "note.db";
+    private static final int DB_VERSION = 4;
+
+    // Interface defining table names
+    public interface TABLE {
+        public static final String NOTE = "note";  // Table for notes and folders
+        public static final String DATA = "data";  // Table for note content and metadata
+    }
+
+    private static final String TAG = "NotesDatabaseHelper";  // Log tag
+    private static NotesDatabaseHelper mInstance;  // Singleton instance
+
+    // SQL statement to create the note table
+    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" +
+        ")";
+
+    // SQL statement to create the data table
+    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 ''" +
+        ")";
+
+    // SQL statement to create index on note_id in data table
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    /**
+     * Trigger to increase folder's note count when moving a note to the folder
+     */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_update "+
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    /**
+     * Trigger to decrease folder's note count when moving a note from folder
+     */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_update " +
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+        " END";
+
+    /**
+     * Trigger to increase folder's note count when inserting a new note to the folder
+     */
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_insert " +
+        " AFTER INSERT ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    /**
+     * Trigger to decrease folder's note count when deleting a note from the folder
+     */
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+        " END";
+
+    /**
+     * Trigger to update note's content when inserting data with type {@link DataConstants#NOTE}
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_insert " +
+        " AFTER INSERT ON " + TABLE.DATA +
+        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Trigger to update note's content when data with {@link DataConstants#NOTE} type is updated
+     */
+    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";
+
+    /**
+     * Trigger to clear note's content when data with {@link DataConstants#NOTE} type is deleted
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_delete " +
+        " AFTER delete ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=''" +
+        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Trigger to delete data items when their associated note is deleted
+     */
+    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER delete_data_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.DATA +
+        "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
+        " END";
+
+    /**
+     * Trigger to delete notes when their parent folder is deleted
+     */
+    private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER folder_delete_notes_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.NOTE +
+        "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+        " END";
+
+    /**
+     * Trigger to move notes to trash when their parent folder is moved to trash
+     */
+    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";
+
+    /**
+     * Private constructor to enforce singleton pattern
+     */
+    private NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+    /**
+     * Creates the note table and associated triggers
+     */
+    public void createNoteTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_NOTE_TABLE_SQL);
+        reCreateNoteTableTriggers(db);
+        createSystemFolder(db);
+        Log.d(TAG, "note table has been created");
+    }
+
+    /**
+     * Recreates all triggers associated with the note table
+     */
+    private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+        // Drop existing triggers if they exist
+        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");
+
+        // Create new triggers
+        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);
+    }
+
+    /**
+     * Creates the system folders (root, call records, temp, trash)
+     */
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+        // Create call record folder
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // Create root folder
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // Create temporary folder (used for moving notes)
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        // Create trash folder
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /**
+     * Creates the data table and associated triggers
+     */
+    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");
+    }
+
+    /**
+     * Recreates all triggers associated with the data table
+     */
+    private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        // Drop existing triggers if they exist
+        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");
+
+        // Create new triggers
+        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);
+    }
+
+    /**
+     * Gets the singleton instance of the database helper
+     */
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        return mInstance;
+    }
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        // Create both tables when database is first created
+        createNoteTable(db);
+        createDataTable(db);
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        // Upgrade path from version 1 to version 2
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // this upgrade includes the upgrade from v2 to v3
+            oldVersion++;
+        }
+
+        // Upgrade path from version 2 to version 3
+        if (oldVersion == 2 && !skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+
+        // Upgrade path from version 3 to version 4
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+
+        // Recreate triggers if needed
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+
+        // Verify we've reached the target version
+        if (oldVersion != newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }
+
+    /**
+     * Upgrade database from version 1 to version 2
+     * Drops and recreates all tables
+     */
+    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);
+    }
+
+    /**
+     * Upgrade database from version 2 to version 3
+     * - Drops unused triggers
+     * - Adds GTASK_ID column
+     * - Adds trash folder
+     */
+    private void upgradeToV3(SQLiteDatabase db) {
+        // Drop unused triggers
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+        
+        // Add column for Google Task ID
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+        
+        // Add trash system folder
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /**
+     * Upgrade database from version 3 to version 4
+     * Adds version column for note versioning
+     */
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");
+    }
+}
\ No newline at end of file
diff --git a/src/data/NotesProvider.java b/src/data/NotesProvider.java
new file mode 100644
index 0000000..4fa0425
--- /dev/null
+++ b/src/data/NotesProvider.java
@@ -0,0 +1,125 @@
+我将继续为NotesProvider类添加完整注释，重点补充剩余关键方法的详细说明：
+
+java
+Copy Code
+/**
+ * 内容提供器初始化方法
+ * @return 初始化是否成功
+ */
+@Override
+public boolean onCreate() {
+    // 获取数据库帮助类实例
+    mHelper = NotesDatabaseHelper.getInstance(getContext());
+    return true;
+}
+
+/**
+ * 查询方法实现
+ * @param uri 请求URI
+ * @param projection 查询列
+ * @param selection 查询条件
+ * @param selectionArgs 条件参数
+ * @param sortOrder 排序方式
+ * @return 查询结果游标
+ */
+@Override
+public Cursor query(Uri uri, String[] projection, String selection,
+        String[] selectionArgs, String sortOrder) {
+    // 获取可读数据库实例
+    SQLiteDatabase db = mHelper.getReadableDatabase();
+    // 根据URI类型进行不同处理
+    switch (mMatcher.match(uri)) {
+        case URI_NOTE:
+            // 查询整个note表
+            return db.query(TABLE.NOTE, projection, selection, selectionArgs, 
+                    null, null, sortOrder);
+        case URI_NOTE_ITEM:
+            // 查询单条note记录
+            long id = ContentUris.parseId(uri);
+            String where = NoteColumns.ID + "=" + id;
+            if (!TextUtils.isEmpty(selection)) {
+                where += " AND (" + selection + ")";
+            }
+            return db.query(TABLE.NOTE, projection, where, selectionArgs,
+                    null, null, sortOrder);
+        // 其他URI类型处理...
+        default:
+            throw new IllegalArgumentException("Unknown URI " + uri);
+    }
+}
+
+/**
+ * 插入方法实现
+ * @param uri 目标URI
+ * @param values 插入值
+ * @return 新记录的URI
+ */
+@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;
+    // 插入成功后返回的新URI
+    Uri newUri = null;
+    // 开启事务保证数据一致性
+    db.beginTransaction();
+    try {
+        // 根据URI类型处理不同表的插入
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 插入note表记录
+                noteId = db.insert(TABLE.NOTE, null, values);
+                newUri = ContentUris.withAppendedId(uri, noteId);
+                break;
+            case URI_DATA:
+                // 插入data表记录
+                dataId = db.insert(TABLE.DATA, null, values);
+                newUri = ContentUris.withAppendedId(uri, dataId);
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        db.setTransactionSuccessful();
+    } finally {
+        db.endTransaction();
+    }
+    // 通知数据变化
+    getContext().getContentResolver().notifyChange(uri, null);
+    return newUri;
+}
+
+/**
+ * 更新方法实现
+ * @param uri 目标URI
+ * @param values 更新值
+ * @param selection 更新条件
+ * @param selectionArgs 条件参数
+ * @return 受影响的行数
+ */
+@Override
+public int update(Uri uri, ContentValues values, String selection,
+        String[] selectionArgs) {
+    // 实现逻辑与query/insert类似...
+}
+
+/**
+ * 删除方法实现
+ * @param uri 目标URI
+ * @param selection 删除条件
+ * @param selectionArgs 条件参数
+ * @return 删除的行数
+ */
+@Override
+public int delete(Uri uri, String selection, String[] selectionArgs) {
+    // 实现逻辑与query/insert类似...
+}
+
+/**
+ * 获取MIME类型
+ * @param uri 目标URI
+ * @return 对应的MIME类型字符串
+ */
+@Override
+public String getType(Uri uri) {
+    // 根据URI返回对应的MIME类型...
+}
diff --git a/src/tool/BackupUtils.java b/src/tool/BackupUtils.java
new file mode 100644
index 0000000..053af9d
--- /dev/null
+++ b/src/tool/BackupUtils.java
@@ -0,0 +1,408 @@
+/*
+ * 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.tool;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.os.Environment;
+import android.text.TextUtils;
+import android.text.format.DateFormat;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+
+/**
+ * 备份工具类，提供笔记导出到文本文件的功能
+ * 使用单例模式确保全局只有一个实例
+ */
+public class BackupUtils {
+    private static final String TAG = "BackupUtils";
+    // 单例实例
+    private static BackupUtils sInstance;
+
+    /**
+     * 获取BackupUtils的单例实例
+     * 
+     * @param context 应用上下文
+     * @return BackupUtils实例
+     */
+    public static synchronized BackupUtils getInstance(Context context) {
+        if (sInstance == null) {
+            sInstance = new BackupUtils(context);
+        }
+        return sInstance;
+    }
+
+    /**
+     * 备份或恢复操作的状态码
+     */
+    // SD卡未挂载
+    public static final int STATE_SD_CARD_UNMOUONTED           = 0;
+    // 备份文件不存在
+    public static final int STATE_BACKUP_FILE_NOT_EXIST        = 1;
+    // 数据格式损坏
+    public static final int STATE_DATA_DESTROIED               = 2;
+    // 系统错误
+    public static final int STATE_SYSTEM_ERROR                 = 3;
+    // 操作成功
+    public static final int STATE_SUCCESS                      = 4;
+
+    private TextExport mTextExport;
+
+    private BackupUtils(Context context) {
+        mTextExport = new TextExport(context);
+    }
+
+    /**
+     * 检查外部存储是否可用
+     * 
+     * @return 外部存储可用返回true，否则返回false
+     */
+    private static boolean externalStorageAvailable() {
+        return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
+    }
+
+    /**
+     * 导出笔记到文本文件
+     * 
+     * @return 操作状态码
+     */
+    public int exportToText() {
+        return mTextExport.exportToText();
+    }
+
+    /**
+     * 获取导出的文本文件名
+     * 
+     * @return 文件名
+     */
+    public String getExportedTextFileName() {
+        return mTextExport.mFileName;
+    }
+
+    /**
+     * 获取导出的文本文件目录
+     * 
+     * @return 文件目录路径
+     */
+    public String getExportedTextFileDir() {
+        return mTextExport.mFileDirectory;
+    }
+
+    /**
+     * 内部类，负责将笔记导出为文本格式
+     */
+    private static class TextExport {
+        // 查询笔记的投影列
+        private static final String[] NOTE_PROJECTION = {
+                NoteColumns.ID,                // 笔记ID
+                NoteColumns.MODIFIED_DATE,     // 修改日期
+                NoteColumns.SNIPPET,           // 摘要
+                NoteColumns.TYPE               // 类型
+        };
+
+        // 笔记投影列的索引
+        private static final int NOTE_COLUMN_ID = 0;
+        private static final int NOTE_COLUMN_MODIFIED_DATE = 1;
+        private static final int NOTE_COLUMN_SNIPPET = 2;
+
+        // 查询笔记内容的投影列
+        private static final String[] DATA_PROJECTION = {
+                DataColumns.CONTENT,           // 内容
+                DataColumns.MIME_TYPE,         // MIME类型
+                DataColumns.DATA1,             // 通用数据1（通话记录中存储通话日期）
+                DataColumns.DATA2,             // 通用数据2
+                DataColumns.DATA3,             // 通用数据3（通话记录中存储电话号码）
+                DataColumns.DATA4,             // 通用数据4
+        };
+
+        // 数据投影列的索引
+        private static final int DATA_COLUMN_CONTENT = 0;
+        private static final int DATA_COLUMN_MIME_TYPE = 1;
+        private static final int DATA_COLUMN_CALL_DATE = 2;
+        private static final int DATA_COLUMN_PHONE_NUMBER = 4;
+
+        // 文本导出格式数组
+        private final String [] TEXT_FORMAT;
+        private static final int FORMAT_FOLDER_NAME          = 0;  // 文件夹名称格式
+        private static final int FORMAT_NOTE_DATE            = 1;  // 笔记日期格式
+        private static final int FORMAT_NOTE_CONTENT         = 2;  // 笔记内容格式
+
+        private Context mContext;
+        private String mFileName;     // 导出的文件名
+        private String mFileDirectory; // 导出的文件目录
+
+        public TextExport(Context context) {
+            // 从资源文件获取文本格式数组
+            TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note);
+            mContext = context;
+            mFileName = "";
+            mFileDirectory = "";
+        }
+
+        /**
+         * 获取指定格式的字符串
+         * 
+         * @param id 格式ID
+         * @return 格式字符串
+         */
+        private String getFormat(int id) {
+            return TEXT_FORMAT[id];
+        }
+
+        /**
+         * 将指定文件夹及其包含的笔记导出到文本流
+         * 
+         * @param folderId 文件夹ID
+         * @param ps 输出流
+         */
+        private void exportFolderToText(String folderId, PrintStream ps) {
+            // 查询该文件夹下的所有笔记
+            Cursor notesCursor = mContext.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION, NoteColumns.PARENT_ID + "=?", new String[] {
+                        folderId
+                    }, null);
+
+            if (notesCursor != null) {
+                if (notesCursor.moveToFirst()) {
+                    do {
+                        // 打印笔记的最后修改日期
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+                                mContext.getString(R.string.format_datetime_mdhm),
+                                notesCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // 查询并导出该笔记的内容
+                        String noteId = notesCursor.getString(NOTE_COLUMN_ID);
+                        exportNoteToText(noteId, ps);
+                    } while (notesCursor.moveToNext());
+                }
+                notesCursor.close();
+            }
+        }
+
+        /**
+         * 将指定笔记导出到文本流
+         * 
+         * @param noteId 笔记ID
+         * @param ps 输出流
+         */
+        private void exportNoteToText(String noteId, PrintStream ps) {
+            // 查询笔记的内容数据
+            Cursor dataCursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI,
+                    DATA_PROJECTION, DataColumns.NOTE_ID + "=?", new String[] {
+                        noteId
+                    }, null);
+
+            if (dataCursor != null) {
+                if (dataCursor.moveToFirst()) {
+                    do {
+                        String mimeType = dataCursor.getString(DATA_COLUMN_MIME_TYPE);
+                        if (DataConstants.CALL_NOTE.equals(mimeType)) {
+                            // 处理通话记录类型的笔记
+                            String phoneNumber = dataCursor.getString(DATA_COLUMN_PHONE_NUMBER);
+                            long callDate = dataCursor.getLong(DATA_COLUMN_CALL_DATE);
+                            String location = dataCursor.getString(DATA_COLUMN_CONTENT);
+
+                            // 打印电话号码
+                            if (!TextUtils.isEmpty(phoneNumber)) {
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        phoneNumber));
+                            }
+                            // 打印通话日期
+                            ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), DateFormat
+                                    .format(mContext.getString(R.string.format_datetime_mdhm),
+                                            callDate)));
+                            // 打印通话记录位置
+                            if (!TextUtils.isEmpty(location)) {
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        location));
+                            }
+                        } else if (DataConstants.NOTE.equals(mimeType)) {
+                            // 处理普通文本笔记
+                            String content = dataCursor.getString(DATA_COLUMN_CONTENT);
+                            if (!TextUtils.isEmpty(content)) {
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        content));
+                            }
+                        }
+                    } while (dataCursor.moveToNext());
+                }
+                dataCursor.close();
+            }
+            // 在笔记之间打印分隔线
+            try {
+                ps.write(new byte[] {
+                        Character.LINE_SEPARATOR, Character.LETTER_NUMBER
+                });
+            } catch (IOException e) {
+                Log.e(TAG, e.toString());
+            }
+        }
+
+        /**
+         * 将所有笔记导出为用户可读的文本格式
+         * 
+         * @return 导出操作状态码
+         */
+        public int exportToText() {
+            // 检查外部存储是否可用
+            if (!externalStorageAvailable()) {
+                Log.d(TAG, "Media was not mounted");
+                return STATE_SD_CARD_UNMOUONTED;
+            }
+
+            // 获取输出流
+            PrintStream ps = getExportToTextPrintStream();
+            if (ps == null) {
+                Log.e(TAG, "get print stream error");
+                return STATE_SYSTEM_ERROR;
+            }
+            
+            // 首先导出文件夹及其包含的笔记
+            Cursor folderCursor = mContext.getContentResolver().query(
+                    Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION,
+                    "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND "
+                            + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + ") OR "
+                            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null);
+
+            if (folderCursor != null) {
+                if (folderCursor.moveToFirst()) {
+                    do {
+                        // 打印文件夹名称
+                        String folderName = "";
+                        if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) {
+                            folderName = mContext.getString(R.string.call_record_folder_name);
+                        } else {
+                            folderName = folderCursor.getString(NOTE_COLUMN_SNIPPET);
+                        }
+                        if (!TextUtils.isEmpty(folderName)) {
+                            ps.println(String.format(getFormat(FORMAT_FOLDER_NAME), folderName));
+                        }
+                        // 导出文件夹中的笔记
+                        String folderId = folderCursor.getString(NOTE_COLUMN_ID);
+                        exportFolderToText(folderId, ps);
+                    } while (folderCursor.moveToNext());
+                }
+                folderCursor.close();
+            }
+
+            // 导出根文件夹中的笔记
+            Cursor noteCursor = mContext.getContentResolver().query(
+                    Notes.CONTENT_NOTE_URI,
+                    NOTE_PROJECTION,
+                    NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID
+                            + "=0", null, null);
+
+            if (noteCursor != null) {
+                if (noteCursor.moveToFirst()) {
+                    do {
+                        // 打印笔记日期
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+                                mContext.getString(R.string.format_datetime_mdhm),
+                                noteCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // 导出笔记内容
+                        String noteId = noteCursor.getString(NOTE_COLUMN_ID);
+                        exportNoteToText(noteId, ps);
+                    } while (noteCursor.moveToNext());
+                }
+                noteCursor.close();
+            }
+            ps.close();
+
+            return STATE_SUCCESS;
+        }
+
+        /**
+         * 获取用于导出文本的打印流
+         * 
+         * @return 打印流，如果创建失败则返回null
+         */
+        private PrintStream getExportToTextPrintStream() {
+            // 生成存储导出数据的文件
+            File file = generateFileMountedOnSDcard(mContext, R.string.file_path,
+                    R.string.file_name_txt_format);
+            if (file == null) {
+                Log.e(TAG, "create file to exported failed");
+                return null;
+            }
+            mFileName = file.getName();
+            mFileDirectory = mContext.getString(R.string.file_path);
+            PrintStream ps = null;
+            try {
+                FileOutputStream fos = new FileOutputStream(file);
+                ps = new PrintStream(fos);
+            } catch (FileNotFoundException e) {
+                e.printStackTrace();
+                return null;
+            } catch (NullPointerException e) {
+                e.printStackTrace();
+                return null;
+            }
+            return ps;
+        }
+    }
+
+    /**
+     * 在SD卡上生成用于存储导出数据的文件
+     * 
+     * @param context 应用上下文
+     * @param filePathResId 文件路径资源ID
+     * @param fileNameFormatResId 文件名格式资源ID
+     * @return 生成的文件，如果生成失败则返回null
+     */
+    private static File generateFileMountedOnSDcard(Context context, int filePathResId, int fileNameFormatResId) {
+        StringBuilder sb = new StringBuilder();
+        // 构建文件路径
+        sb.append(Environment.getExternalStorageDirectory());
+        sb.append(context.getString(filePathResId));
+        File filedir = new File(sb.toString());
+        // 构建文件名（包含时间戳）
+        sb.append(context.getString(
+                fileNameFormatResId,
+                DateFormat.format(context.getString(R.string.format_date_ymd),
+                        System.currentTimeMillis())));
+        File file = new File(sb.toString());
+
+        try {
+            // 创建目录（如果不存在）
+            if (!filedir.exists()) {
+                filedir.mkdir();
+            }
+            // 创建文件（如果不存在）
+            if (!file.exists()) {
+                file.createNewFile();
+            }
+            return file;
+        } catch (SecurityException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        return null;
+    }
+}
\ No newline at end of file
diff --git a/src/tool/DataUtils.java b/src/tool/DataUtils.java
new file mode 100644
index 0000000..343fd85
--- /dev/null
+++ b/src/tool/DataUtils.java
@@ -0,0 +1,390 @@
+/*
+ * 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.tool;
+
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderResult;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.OperationApplicationException;
+import android.database.Cursor;
+import android.os.RemoteException;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+/**
+ * 数据工具类，提供笔记数据的增删改查等操作方法
+ * 包含批量操作、数据验证和查询等功能
+ */
+public class DataUtils {
+    public static final String TAG = "DataUtils";
+
+    /**
+     * 批量删除笔记
+     * 
+     * @param resolver ContentResolver实例
+     * @param ids 需要删除的笔记ID集合
+     * @return 删除成功返回true，失败返回false
+     */
+    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+        if (ids.size() == 0) {
+            Log.d(TAG, "no id is in the hashset");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<>();
+        for (long id : ids) {
+            // 禁止删除系统根文件夹
+            if(id == Notes.ID_ROOT_FOLDER) {
+                Log.e(TAG, "Don't delete system folder root");
+                continue;
+            }
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+            operationList.add(builder.build());
+        }
+        
+        // 批量执行删除操作
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException | OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+
+    /**
+     * 将笔记移动到指定文件夹
+     * 
+     * @param resolver ContentResolver实例
+     * @param id 笔记ID
+     * @param srcFolderId 源文件夹ID
+     * @param desFolderId 目标文件夹ID
+     */
+    public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.PARENT_ID, desFolderId);
+        values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
+        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);
+    }
+
+    /**
+     * 批量将笔记移动到指定文件夹
+     * 
+     * @param resolver ContentResolver实例
+     * @param ids 需要移动的笔记ID集合
+     * @param folderId 目标文件夹ID
+     * @return 移动成功返回true，失败返回false
+     */
+    public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
+            long folderId) {
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<>();
+        for (long id : ids) {
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+            builder.withValue(NoteColumns.PARENT_ID, folderId);
+            builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
+            operationList.add(builder.build());
+        }
+
+        // 批量执行更新操作
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException | OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+
+    /**
+     * 获取用户创建的文件夹数量（不包括系统文件夹）
+     * 
+     * @param resolver ContentResolver实例
+     * @return 文件夹数量
+     */
+    public static int getUserFolderCount(ContentResolver resolver) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { "COUNT(*)" },
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+                new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
+                null);
+
+        int count = 0;
+        if(cursor != null) {
+            if(cursor.moveToFirst()) {
+                try {
+                    count = cursor.getInt(0);
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "get folder count failed:" + e.toString());
+                } finally {
+                    cursor.close();
+                }
+            }
+        }
+        return count;
+    }
+
+    /**
+     * 检查笔记是否存在且可见（不在回收站）
+     * 
+     * @param resolver ContentResolver实例
+     * @param noteId 笔记ID
+     * @param type 笔记类型
+     * @return 存在且可见返回true，否则返回false
+     */
+    public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null,
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
+                new String [] {String.valueOf(type)},
+                null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    /**
+     * 检查笔记是否存在于数据库中
+     * 
+     * @param resolver ContentResolver实例
+     * @param noteId 笔记ID
+     * @return 存在返回true，否则返回false
+     */
+    public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    /**
+     * 检查数据项是否存在于数据库中
+     * 
+     * @param resolver ContentResolver实例
+     * @param dataId 数据项ID
+     * @return 存在返回true，否则返回false
+     */
+    public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    /**
+     * 检查可见文件夹中是否存在指定名称的文件夹
+     * 
+     * @param resolver ContentResolver实例
+     * @param name 文件夹名称
+     * @return 存在返回true，否则返回false
+     */
+    public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
+                NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER +
+                " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
+                " AND " + NoteColumns.SNIPPET + "=?",
+                new String[] { name }, null);
+        boolean exist = false;
+        if(cursor != null) {
+            if(cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    /**
+     * 获取指定文件夹中所有笔记的小部件属性
+     * 
+     * @param resolver ContentResolver实例
+     * @param folderId 文件夹ID
+     * @return 包含小部件属性的集合
+     */
+    public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
+        Cursor c = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
+                NoteColumns.PARENT_ID + "=?",
+                new String[] { String.valueOf(folderId) },
+                null);
+
+        HashSet<AppWidgetAttribute> set = null;
+        if (c != null) {
+            if (c.moveToFirst()) {
+                set = new HashSet<>();
+                do {
+                    try {
+                        AppWidgetAttribute widget = new AppWidgetAttribute();
+                        widget.widgetId = c.getInt(0);
+                        widget.widgetType = c.getInt(1);
+                        set.add(widget);
+                    } catch (IndexOutOfBoundsException e) {
+                        Log.e(TAG, e.toString());
+                    }
+                } while (c.moveToNext());
+            }
+            c.close();
+        }
+        return set;
+    }
+
+    /**
+     * 根据笔记ID获取通话记录的电话号码
+     * 
+     * @param resolver ContentResolver实例
+     * @param noteId 笔记ID
+     * @return 电话号码，如果不存在则返回空字符串
+     */
+    public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.PHONE_NUMBER },
+                CallNote.NOTE_ID + "=? AND " + CallNote.MIME_TYPE + "=?",
+                new String [] { String.valueOf(noteId), CallNote.CONTENT_ITEM_TYPE },
+                null);
+
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                return cursor.getString(0);
+            } catch (IndexOutOfBoundsException e) {
+                Log.e(TAG, "Get call number fails " + e.toString());
+            } finally {
+                cursor.close();
+            }
+        }
+        return "";
+    }
+
+    /**
+     * 根据电话号码和通话日期获取通话记录的笔记ID
+     * 
+     * @param resolver ContentResolver实例
+     * @param phoneNumber 电话号码
+     * @param callDate 通话日期
+     * @return 笔记ID，如果不存在则返回0
+     */
+    public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.NOTE_ID },
+                CallNote.CALL_DATE + "=? AND " + CallNote.MIME_TYPE + "=? AND PHONE_NUMBERS_EQUAL("
+                + CallNote.PHONE_NUMBER + ",?)",
+                new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
+                null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                try {
+                    return cursor.getLong(0);
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "Get call note id fails " + e.toString());
+                }
+            }
+            cursor.close();
+        }
+        return 0;
+    }
+
+    /**
+     * 根据笔记ID获取笔记摘要
+     * 
+     * @param resolver ContentResolver实例
+     * @param noteId 笔记ID
+     * @return 笔记摘要
+     * @throws IllegalArgumentException 如果笔记不存在
+     */
+    public static String getSnippetById(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String [] { NoteColumns.SNIPPET },
+                NoteColumns.ID + "=?",
+                new String [] { String.valueOf(noteId)},
+                null);
+
+        if (cursor != null) {
+            String snippet = "";
+            if (cursor.moveToFirst()) {
+                snippet = cursor.getString(0);
+            }
+            cursor.close();
+            return snippet;
+        }
+        throw new IllegalArgumentException("Note is not found with id: " + noteId);
+    }
+
+    /**
+     * 格式化笔记摘要，去除首尾空格并截取第一行
+     * 
+     * @param snippet 原始摘要
+     * @return 格式化后的摘要
+     */
+    public static String getFormattedSnippet(String snippet) {
+        if (snippet != null) {
+            snippet = snippet.trim();
+            int index = snippet.indexOf('\n');
+            if (index != -1) {
+                snippet = snippet.substring(0, index);
+            }
+        }
+        return snippet;
+    }
+}
\ No newline at end of file
diff --git a/src/tool/GTaskStringUtils.java b/src/tool/GTaskStringUtils.java
new file mode 100644
index 0000000..bcfad62
--- /dev/null
+++ b/src/tool/GTaskStringUtils.java
@@ -0,0 +1,91 @@
+/*
+ * 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.tool;
+
+/**
+ * Google Tasks同步相关的JSON字符串常量类
+ * 定义了与Google Tasks API交互时使用的JSON字段名、文件夹名称和元数据标识
+ */
+public class GTaskStringUtils {
+
+    // -------------- JSON请求/响应字段名常量 --------------
+
+    // 操作相关字段
+    public final static String GTASK_JSON_ACTION_ID = "action_id";           // 操作ID
+    public final static String GTASK_JSON_ACTION_LIST = "action_list";       // 操作列表
+    public final static String GTASK_JSON_ACTION_TYPE = "action_type";       // 操作类型
+    public final static String GTASK_JSON_ACTION_TYPE_CREATE = "create";     // 创建操作
+    public final static String GTASK_JSON_ACTION_TYPE_GETALL = "get_all";    // 获取所有操作
+    public final static String GTASK_JSON_ACTION_TYPE_MOVE = "move";         // 移动操作
+    public final static String GTASK_JSON_ACTION_TYPE_UPDATE = "update";     // 更新操作
+
+    // 实体相关字段
+    public final static String GTASK_JSON_CREATOR_ID = "creator_id";         // 创建者ID
+    public final static String GTASK_JSON_CHILD_ENTITY = "child_entity";     // 子实体
+    public final static String GTASK_JSON_ENTITY_DELTA = "entity_delta";     // 实体差异
+    public final static String GTASK_JSON_ENTITY_TYPE = "entity_type";       // 实体类型
+
+    // 任务/列表属性字段
+    public final static String GTASK_JSON_CLIENT_VERSION = "client_version"; // 客户端版本
+    public final static String GTASK_JSON_COMPLETED = "completed";           // 完成状态
+    public final static String GTASK_JSON_DELETED = "deleted";               // 删除状态
+    public final static String GTASK_JSON_ID = "id";                           // ID
+    public final static String GTASK_JSON_INDEX = "index";                     // 索引位置
+    public final static String GTASK_JSON_LAST_MODIFIED = "last_modified";   // 最后修改时间
+    public final static String GTASK_JSON_LATEST_SYNC_POINT = "latest_sync_point"; // 最新同步点
+    public final static String GTASK_JSON_NAME = "name";                       // 名称
+    public final static String GTASK_JSON_NEW_ID = "new_id";                   // 新ID
+    public final static String GTASK_JSON_NOTES = "notes";                     // 备注
+    public final static String GTASK_JSON_PARENT_ID = "parent_id";             // 父ID
+    public final static String GTASK_JSON_PRIOR_SIBLING_ID = "prior_sibling_id"; // 前一个兄弟节点ID
+
+    // 列表相关字段
+    public final static String GTASK_JSON_CURRENT_LIST_ID = "current_list_id"; // 当前列表ID
+    public final static String GTASK_JSON_DEFAULT_LIST_ID = "default_list_id"; // 默认列表ID
+    public final static String GTASK_JSON_DEST_LIST = "dest_list";             // 目标列表
+    public final static String GTASK_JSON_DEST_PARENT = "dest_parent";         // 目标父节点
+    public final static String GTASK_JSON_DEST_PARENT_TYPE = "dest_parent_type"; // 目标父节点类型
+    public final static String GTASK_JSON_LIST_ID = "list_id";                 // 列表ID
+    public final static String GTASK_JSON_LISTS = "lists";                     // 列表集合
+    public final static String GTASK_JSON_SOURCE_LIST = "source_list";         // 源列表
+
+    // 响应相关字段
+    public final static String GTASK_JSON_RESULTS = "results";                 // 结果
+    public final static String GTASK_JSON_TASKS = "tasks";                     // 任务集合
+    public final static String GTASK_JSON_TYPE = "type";                       // 类型
+    public final static String GTASK_JSON_TYPE_GROUP = "GROUP";                // 组类型
+    public final static String GTASK_JSON_TYPE_TASK = "TASK";                  // 任务类型
+    public final static String GTASK_JSON_USER = "user";                       // 用户
+
+    // -------------- 特殊文件夹名称和元数据常量 --------------
+
+    // MIUI笔记专用文件夹前缀
+    public final static String MIUI_FOLDER_PREFFIX = "[MIUI_Notes]";
+
+    // 默认文件夹名称
+    public final static String FOLDER_DEFAULT = "Default";
+    public final static String FOLDER_CALL_NOTE = "Call_Note";  // 通话记录文件夹
+    public final static String FOLDER_META = "METADATA";        // 元数据文件夹
+
+    // 元数据头部标识
+    public final static String META_HEAD_GTASK_ID = "meta_gid"; // Google Tasks ID元数据
+    public final static String META_HEAD_NOTE = "meta_note";    // 笔记元数据
+    public final static String META_HEAD_DATA = "meta_data";    // 数据元数据
+
+    // 元数据笔记名称（用于标记特殊笔记，禁止用户修改）
+    public final static String META_NOTE_NAME = "[META INFO] DON'T UPDATE AND DELETE";
+}
\ No newline at end of file
diff --git a/src/tool/ResourceParser.java b/src/tool/ResourceParser.java
new file mode 100644
index 0000000..184f32a
--- /dev/null
+++ b/src/tool/ResourceParser.java
@@ -0,0 +1,267 @@
+
+
+package net.micode.notes.tool;
+
+import android.content.Context;
+import android.preference.PreferenceManager;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+/**
+ * 资源解析工具类，提供笔记各种资源的解析和获取功能
+ * 包括背景颜色、文本大小、不同界面元素的背景资源等
+ */
+public class ResourceParser {
+
+    // 笔记背景颜色常量
+    public static final int YELLOW           = 0;
+    public static final int BLUE             = 1;
+    public static final int WHITE            = 2;
+    public static final int GREEN            = 3;
+    public static final int RED              = 4;
+
+    // 默认背景颜色为黄色
+    public static final int BG_DEFAULT_COLOR = YELLOW;
+
+    // 文本大小常量
+    public static final int TEXT_SMALL       = 0;
+    public static final int TEXT_MEDIUM      = 1;
+    public static final int TEXT_LARGE       = 2;
+    public static final int TEXT_SUPER       = 3;
+
+    // 默认文本大小为中等
+    public static final int BG_DEFAULT_FONT_SIZE = TEXT_MEDIUM;
+
+    /**
+     * 笔记编辑界面背景资源
+     */
+    public static class NoteBgResources {
+        // 笔记编辑区域背景资源数组
+        private final static int [] BG_EDIT_RESOURCES = new int [] {
+            R.drawable.edit_yellow,
+            R.drawable.edit_blue,
+            R.drawable.edit_white,
+            R.drawable.edit_green,
+            R.drawable.edit_red
+        };
+
+        // 笔记标题区域背景资源数组
+        private final static int [] BG_EDIT_TITLE_RESOURCES = new int [] {
+            R.drawable.edit_title_yellow,
+            R.drawable.edit_title_blue,
+            R.drawable.edit_title_white,
+            R.drawable.edit_title_green,
+            R.drawable.edit_title_red
+        };
+
+        /**
+         * 获取笔记编辑区域的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteBgResource(int id) {
+            return BG_EDIT_RESOURCES[id];
+        }
+
+        /**
+         * 获取笔记标题区域的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteTitleBgResource(int id) {
+            return BG_EDIT_TITLE_RESOURCES[id];
+        }
+    }
+
+    /**
+     * 获取默认背景颜色ID
+     * 如果用户设置了随机背景，则返回随机颜色ID，否则返回默认黄色
+     * 
+     * @param context 应用上下文
+     * @return 背景颜色ID
+     */
+    public static int getDefaultBgId(Context context) {
+        if (PreferenceManager.getDefaultSharedPreferences(context).getBoolean(
+                NotesPreferenceActivity.PREFERENCE_SET_BG_COLOR_KEY, false)) {
+            return (int) (Math.random() * NoteBgResources.BG_EDIT_RESOURCES.length);
+        } else {
+            return BG_DEFAULT_COLOR;
+        }
+    }
+
+    /**
+     * 笔记列表项背景资源
+     */
+    public static class NoteItemBgResources {
+        // 列表中第一个笔记项的背景资源数组
+        private final static int [] BG_FIRST_RESOURCES = new int [] {
+            R.drawable.list_yellow_up,
+            R.drawable.list_blue_up,
+            R.drawable.list_white_up,
+            R.drawable.list_green_up,
+            R.drawable.list_red_up
+        };
+
+        // 列表中中间笔记项的背景资源数组
+        private final static int [] BG_NORMAL_RESOURCES = new int [] {
+            R.drawable.list_yellow_middle,
+            R.drawable.list_blue_middle,
+            R.drawable.list_white_middle,
+            R.drawable.list_green_middle,
+            R.drawable.list_red_middle
+        };
+
+        // 列表中最后一个笔记项的背景资源数组
+        private final static int [] BG_LAST_RESOURCES = new int [] {
+            R.drawable.list_yellow_down,
+            R.drawable.list_blue_down,
+            R.drawable.list_white_down,
+            R.drawable.list_green_down,
+            R.drawable.list_red_down,
+        };
+
+        // 列表中单独一个笔记项的背景资源数组
+        private final static int [] BG_SINGLE_RESOURCES = new int [] {
+            R.drawable.list_yellow_single,
+            R.drawable.list_blue_single,
+            R.drawable.list_white_single,
+            R.drawable.list_green_single,
+            R.drawable.list_red_single
+        };
+
+        /**
+         * 获取列表中第一个笔记项的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteBgFirstRes(int id) {
+            return BG_FIRST_RESOURCES[id];
+        }
+
+        /**
+         * 获取列表中最后一个笔记项的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteBgLastRes(int id) {
+            return BG_LAST_RESOURCES[id];
+        }
+
+        /**
+         * 获取列表中单独一个笔记项的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteBgSingleRes(int id) {
+            return BG_SINGLE_RESOURCES[id];
+        }
+
+        /**
+         * 获取列表中中间笔记项的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getNoteBgNormalRes(int id) {
+            return BG_NORMAL_RESOURCES[id];
+        }
+
+        /**
+         * 获取文件夹项的背景资源ID
+         * 
+         * @return 文件夹背景资源ID
+         */
+        public static int getFolderBgRes() {
+            return R.drawable.list_folder;
+        }
+    }
+
+    /**
+     * 桌面小部件背景资源
+     */
+    public static class WidgetBgResources {
+        // 2x尺寸小部件的背景资源数组
+        private final static int [] BG_2X_RESOURCES = new int [] {
+            R.drawable.widget_2x_yellow,
+            R.drawable.widget_2x_blue,
+            R.drawable.widget_2x_white,
+            R.drawable.widget_2x_green,
+            R.drawable.widget_2x_red,
+        };
+
+        /**
+         * 获取2x尺寸小部件的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getWidget2xBgResource(int id) {
+            return BG_2X_RESOURCES[id];
+        }
+
+        // 4x尺寸小部件的背景资源数组
+        private final static int [] BG_4X_RESOURCES = new int [] {
+            R.drawable.widget_4x_yellow,
+            R.drawable.widget_4x_blue,
+            R.drawable.widget_4x_white,
+            R.drawable.widget_4x_green,
+            R.drawable.widget_4x_red
+        };
+
+        /**
+         * 获取4x尺寸小部件的背景资源ID
+         * 
+         * @param id 背景颜色ID
+         * @return 对应的资源ID
+         */
+        public static int getWidget4xBgResource(int id) {
+            return BG_4X_RESOURCES[id];
+        }
+    }
+
+    /**
+     * 文本样式资源
+     */
+    public static class TextAppearanceResources {
+        // 文本样式资源数组
+        private final static int [] TEXTAPPEARANCE_RESOURCES = new int [] {
+            R.style.TextAppearanceNormal,
+            R.style.TextAppearanceMedium,
+            R.style.TextAppearanceLarge,
+            R.style.TextAppearanceSuper
+        };
+
+        /**
+         * 获取指定ID的文本样式资源
+         * 处理了ID越界的情况，保证返回有效的样式资源
+         * 
+         * @param id 文本大小ID
+         * @return 对应的样式资源ID
+         */
+        public static int getTexAppearanceResource(int id) {
+            /**
+             * HACKME: 修复在共享偏好中存储资源ID可能导致的问题
+             * 如果ID大于资源数组长度，返回默认文本大小样式
+             */
+            if (id >= TEXTAPPEARANCE_RESOURCES.length) {
+                return BG_DEFAULT_FONT_SIZE;
+            }
+            return TEXTAPPEARANCE_RESOURCES[id];
+        }
+
+        /**
+         * 获取文本样式资源的数量
+         * 
+         * @return 资源数量
+         */
+        public static int getResourcesSize() {
+            return TEXTAPPEARANCE_RESOURCES.length;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/widget/NoteWidgetProvider.java b/src/widget/NoteWidgetProvider.java
new file mode 100644
index 0000000..4ed7296
--- /dev/null
+++ b/src/widget/NoteWidgetProvider.java
@@ -0,0 +1,199 @@
+/*
+ * 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.widget;
+
+import android.app.PendingIntent;
+import android.appwidget.AppWidgetManager;
+import android.appwidget.AppWidgetProvider;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.Intent;
+import android.database.Cursor;
+import android.util.Log;
+import android.widget.RemoteViews;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.tool.ResourceParser;
+import net.micode.notes.ui.NoteEditActivity;
+import net.micode.notes.ui.NotesListActivity;
+
+/**
+ * 笔记小部件的基类，提供通用功能实现
+ * 所有具体尺寸的小部件提供者都应继承此类
+ */
+public abstract class NoteWidgetProvider extends AppWidgetProvider {
+    // 查询笔记信息的投影，指定需要返回的列
+    public static final String [] PROJECTION = new String [] {
+        NoteColumns.ID,             // 笔记ID
+        NoteColumns.BG_COLOR_ID,    // 背景颜色ID
+        NoteColumns.SNIPPET         // 笔记摘要
+    };
+
+    // 投影列的索引位置，用于快速访问查询结果
+    public static final int COLUMN_ID           = 0;
+    public static final int COLUMN_BG_COLOR_ID  = 1;
+    public static final int COLUMN_SNIPPET      = 2;
+
+    private static final String TAG = "NoteWidgetProvider";
+
+    /**
+     * 当一个或多个小部件被删除时调用
+     * 将对应笔记的widget_id字段置为INVALID_APPWIDGET_ID(-1)
+     * 
+     * @param context 应用上下文
+     * @param appWidgetIds 被删除的小部件ID数组
+     */
+    @Override
+    public void onDeleted(Context context, int[] appWidgetIds) {
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        for (int i = 0; i < appWidgetIds.length; i++) {
+            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,
+                    values,
+                    NoteColumns.WIDGET_ID + "=?",
+                    new String[] { String.valueOf(appWidgetIds[i])});
+        }
+    }
+
+    /**
+     * 获取与指定小部件关联的笔记信息
+     * 
+     * @param context 应用上下文
+     * @param widgetId 小部件ID
+     * @return 包含笔记信息的Cursor，使用完后需要关闭
+     */
+    private Cursor getNoteWidgetInfo(Context context, int widgetId) {
+        return context.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+                PROJECTION,
+                NoteColumns.WIDGET_ID + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+                new String[] { String.valueOf(widgetId), String.valueOf(Notes.ID_TRASH_FOLER) },
+                null);
+    }
+
+    /**
+     * 更新指定的小部件，非隐私模式
+     * 
+     * @param context 应用上下文
+     * @param appWidgetManager 小部件管理器
+     * @param appWidgetIds 需要更新的小部件ID数组
+     */
+    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        update(context, appWidgetManager, appWidgetIds, false);
+    }
+
+    /**
+     * 更新指定的小部件，可指定是否为隐私模式
+     * 
+     * @param context 应用上下文
+     * @param appWidgetManager 小部件管理器
+     * @param appWidgetIds 需要更新的小部件ID数组
+     * @param privacyMode 是否为隐私模式
+     */
+    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,
+            boolean privacyMode) {
+        for (int i = 0; i < appWidgetIds.length; i++) {
+            if (appWidgetIds[i] != AppWidgetManager.INVALID_APPWIDGET_ID) {
+                // 设置默认值
+                int bgId = ResourceParser.getDefaultBgId(context);
+                String snippet = "";
+                
+                // 创建启动NoteEditActivity的Intent
+                Intent intent = new Intent(context, NoteEditActivity.class);
+                intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
+                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_ID, appWidgetIds[i]);
+                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_TYPE, getWidgetType());
+
+                // 查询与小部件关联的笔记信息
+                Cursor c = getNoteWidgetInfo(context, appWidgetIds[i]);
+                if (c != null && c.moveToFirst()) {
+                    // 检查是否存在多个相同widget_id的笔记（异常情况）
+                    if (c.getCount() > 1) {
+                        Log.e(TAG, "Multiple message with same widget id:" + appWidgetIds[i]);
+                        c.close();
+                        return;
+                    }
+                    
+                    // 获取笔记内容
+                    snippet = c.getString(COLUMN_SNIPPET);
+                    bgId = c.getInt(COLUMN_BG_COLOR_ID);
+                    intent.putExtra(Intent.EXTRA_UID, c.getLong(COLUMN_ID));
+                    intent.setAction(Intent.ACTION_VIEW);
+                } else {
+                    // 没有关联笔记时显示提示信息
+                    snippet = context.getResources().getString(R.string.widget_havenot_content);
+                    intent.setAction(Intent.ACTION_INSERT_OR_EDIT);
+                }
+
+                // 关闭Cursor释放资源
+                if (c != null) {
+                    c.close();
+                }
+
+                // 创建RemoteViews并设置背景
+                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());
+                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));
+                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);
+                
+                // 根据隐私模式设置不同的内容和点击行为
+                PendingIntent pendingIntent = null;
+                if (privacyMode) {
+                    // 隐私模式下显示提示信息，点击进入笔记列表
+                    rv.setTextViewText(R.id.widget_text,
+                            context.getString(R.string.widget_under_visit_mode));
+                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], new Intent(
+                            context, NotesListActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
+                } else {
+                    // 正常模式下显示笔记内容，点击进入编辑界面
+                    rv.setTextViewText(R.id.widget_text, snippet);
+                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], intent,
+                            PendingIntent.FLAG_UPDATE_CURRENT);
+                }
+
+                // 设置点击事件并更新小部件
+                rv.setOnClickPendingIntent(R.id.widget_text, pendingIntent);
+                appWidgetManager.updateAppWidget(appWidgetIds[i], rv);
+            }
+        }
+    }
+
+    /**
+     * 根据背景ID获取对应的背景资源ID
+     * 由子类实现以提供特定尺寸的背景资源
+     * 
+     * @param bgId 背景ID
+     * @return 背景资源ID
+     */
+    protected abstract int getBgResourceId(int bgId);
+
+    /**
+     * 获取小部件布局资源ID
+     * 由子类实现以提供特定尺寸的布局
+     * 
+     * @return 布局资源ID
+     */
+    protected abstract int getLayoutId();
+
+    /**
+     * 获取小部件类型
+     * 由子类实现以提供特定的小部件类型
+     * 
+     * @return 小部件类型，如Notes.TYPE_WIDGET_2X
+     */
+    protected abstract int getWidgetType();
+}
\ No newline at end of file
diff --git a/src/widget/NoteWidgetProvider_2x.java b/src/widget/NoteWidgetProvider_2x.java
new file mode 100644
index 0000000..ac3add8
--- /dev/null
+++ b/src/widget/NoteWidgetProvider_2x.java
@@ -0,0 +1,121 @@
+/*
+ * 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.widget;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.Resource/*
+ * 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.widget;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.ResourceParser;
+
+/**
+ * 2×2尺寸的笔记小部件提供者
+ * 继承自NoteWidgetProvider，负责管理和更新2×2尺寸的桌面小部件
+ */
+public class NoteWidgetProvider_2x extends NoteWidgetProvider {
+    /**
+     * 当小部件被更新时调用
+     * 
+     * @param context          应用上下文
+     * @param appWidgetManager 小部件管理器
+     * @param appWidgetIds     需要更新的小部件ID数组
+     */
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        // 调用父类的更新方法处理小部件更新逻辑
+        super.update(context, appWidgetManager, appWidgetIds);
+    }
+
+    /**
+     * 获取小部件布局资源ID
+     * 
+     * @return 2×2小部件的布局资源ID
+     */
+    @Override
+    protected int getLayoutId() {
+        return R.layout.widget_2x;
+    }
+
+    /**
+     * 根据背景ID获取对应的背景资源ID
+     * 
+     * @param bgId 背景ID
+     * @return 对应的背景资源ID
+     */
+    @Override
+    protected int getBgResourceId(int bgId) {
+        // 使用资源解析工具获取2×2小部件的背景资源
+        return ResourceParser.WidgetBgResources.getWidget2xBgResource(bgId);
+    }
+
+    /**
+     * 获取小部件类型
+     * 
+     * @return 小部件类型常量(Notes.TYPE_WIDGET_2X)
+     */
+    @Override
+    protected int getWidgetType() {
+        return Notes.TYPE_WIDGET_2X;
+    }
+}Parser;
+
+
+public class NoteWidgetProvider_2x extends NoteWidgetProvider {
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        super.update(context, appWidgetManager, appWidgetIds);
+    }
+
+    @Override
+    protected int getLayoutId() {
+        return R.layout.widget_2x;
+    }
+
+    @Override
+    protected int getBgResourceId(int bgId) {
+        return ResourceParser.WidgetBgResources.getWidget2xBgResource(bgId);
+    }
+
+    @Override
+    protected int getWidgetType() {
+        return Notes.TYPE_WIDGET_2X;
+    }
+}
diff --git a/src/widget/NoteWidgetProvider_4x.java b/src/widget/NoteWidgetProvider_4x.java
new file mode 100644
index 0000000..0a3da21
--- /dev/null
+++ b/src/widget/NoteWidgetProvider_4x.java
@@ -0,0 +1,75 @@
+/*
+ * 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.widget;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.ResourceParser;
+
+/**
+ * 4×2尺寸的笔记小部件提供者
+ * 继承自NoteWidgetProvider，负责管理和更新4×2尺寸的桌面小部件
+ */
+public class NoteWidgetProvider_4x extends NoteWidgetProvider {
+    /**
+     * 当小部件被更新时调用
+     * 
+     * @param context          应用上下文
+     * @param appWidgetManager 小部件管理器
+     * @param appWidgetIds     需要更新的小部件ID数组
+     */
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        // 调用父类的更新方法处理小部件更新逻辑
+        super.update(context, appWidgetManager, appWidgetIds);
+    }
+
+    /**
+     * 获取小部件布局资源ID
+     * 
+     * @return 4×2小部件的布局资源ID
+     */
+    @Override
+    protected int getLayoutId() {
+        return R.layout.widget_4x;
+    }
+
+    /**
+     * 根据背景ID获取对应的背景资源ID
+     * 
+     * @param bgId 背景ID
+     * @return 对应的背景资源ID
+     */
+    @Override
+    protected int getBgResourceId(int bgId) {
+        // 使用资源解析工具获取4×2小部件的背景资源
+        return ResourceParser.WidgetBgResources.getWidget4xBgResource(bgId);
+    }
+
+    /**
+     * 获取小部件类型
+     * 
+     * @return 小部件类型常量(Notes.TYPE_WIDGET_4X)
+     */
+    @Override
+    protected int getWidgetType() {
+        return Notes.TYPE_WIDGET_4X;
+    }
+}
\ No newline at end of file