云同步功能实现

src/Notesmaster/.idea/deploymentTargetSelector.xml

@@ -4,6 +4,14 @@
     <selectionStates>
       <SelectionState runConfigName="app">
         <option name="selectionMode" value="DROPDOWN" />
+        <DropdownSelection timestamp="2026-01-30T10:15:59.196226600Z">
+          <Target type="DEFAULT_BOOT">
+            <handle>
+              <DeviceId pluginId="LocalEmulator" identifier="path=C:\Users\啊？\.android\avd\Pixel_4a_API_31.avd" />
+            </handle>
+          </Target>
+        </DropdownSelection>
+        <DialogSelection />
       </SelectionState>
     </selectionStates>
   </component>

src/Notesmaster/app/.project

@@ -5,6 +5,11 @@
 	<projects>
 	</projects>
 	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
 		<buildCommand>
 			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
 			<arguments>
@@ -12,6 +17,7 @@
 		</buildCommand>
 	</buildSpec>
 	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
 		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
 	</natures>
 	<filteredResources>

src/Notesmaster/app/build.gradle.kts

@@ -1,3 +1,5 @@
+import java.util.Properties
+
 plugins {
     alias(libs.plugins.android.application)
 }
@@ -10,6 +12,7 @@ android {
     // 启用ViewBinding
     buildFeatures {
         viewBinding = true
+        buildConfig = true
     }
 
     defaultConfig {
@@ -20,6 +23,18 @@ android {
         versionName = "1.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        // Load Aliyun config from local.properties
+        val localProperties = Properties()
+        val localFile = rootProject.file("local.properties")
+        if (localFile.exists()) {
+            localFile.inputStream().use { localProperties.load(it) }
+        }
+
+        buildConfigField("String", "ALIYUN_APP_KEY", "\"${localProperties.getProperty("aliyun.app.key", "")}\"")
+        buildConfigField("String", "ALIYUN_APP_SECRET", "\"${localProperties.getProperty("aliyun.app.secret", "")}\"")
+        buildConfigField("String", "ALIYUN_SPACE_ID", "\"${localProperties.getProperty("aliyun.space.id", "")}\"")
+        buildConfigField("String", "ALIYUN_ENDPOINT", "\"${localProperties.getProperty("aliyun.endpoint", "")}\"")
     }
 
     buildTypes {
@@ -64,4 +79,16 @@ dependencies {
     testImplementation("org.mockito:mockito-core:5.7.0")
     androidTestImplementation(libs.ext.junit)
     androidTestImplementation(libs.espresso.core)
+
+    // Cloud sync dependencies
+    implementation("com.google.code.gson:gson:2.10.1")
+    implementation("androidx.work:work-runtime:2.8.1")
+    implementation("com.squareup.okhttp3:okhttp:4.12.0")
+    
+    // Alibaba Cloud EMAS Push SDK
+    implementation("com.aliyun.ams:alicloud-android-push:3.10.1")
+    implementation("com.aliyun.ams:alicloud-android-utils:1.1.3")
+    
+    // Note: EMAS Serverless SDK needs to be downloaded from Aliyun console
+    // For now, use HTTP API approach with OkHttp
 }

src/Notesmaster/app/src/main/AndroidManifest.xml

@@ -23,6 +23,14 @@
     <!-- 允许接收系统启动完成广播，用于初始化闹钟 -->
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
+    <!-- 阿里云推送服务权限 -->
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
+    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.VIBRATE" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+
     <!-- ==================== 应用配置 ==================== -->
     <application
         android:name=".NotesApplication"
@@ -179,6 +187,18 @@
             android:process=":remote" >
         </receiver>
 
+        <!-- ==================== 推送消息接收器 ==================== -->
+        <!-- 接收云端同步通知消息 -->
+        <receiver
+            android:name=".sync.NotesPushMessageReceiver"
+            android:enabled="true"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="com.alibaba.push2.action.NOTIFICATION_OPENED" />
+                <action android:name="com.alibaba.push2.action.MESSAGE_RECEIVED" />
+            </intent-filter>
+        </receiver>
+
         <!-- ==================== 闹钟提醒活动 ==================== -->
         <!-- 显示闹钟提醒界面 -->
         <activity
@@ -205,6 +225,20 @@
             android:windowSoftInputMode="stateVisible|adjustResize">
         </activity>
 
+        <!-- ==================== 登录/注册活动 ==================== -->
+        <activity
+            android:name=".ui.LoginActivity"
+            android:label="登录"
+            android:theme="@style/Theme.Notesmaster"
+            android:exported="false" />
+
+        <!-- ==================== 云同步设置活动 ==================== -->
+        <activity
+            android:name=".ui.SyncActivity"
+            android:label="@string/sync_title"
+            android:theme="@style/Theme.Notesmaster"
+            android:exported="false" />
+
          <!-- ==================== 同步服务 ==================== -->
          <!-- Google任务同步服务，用于与Google Tasks同步数据 -->
          <!-- 暂时禁用同步功能，为未来云同步开发暂留代码 -->
@@ -216,6 +250,14 @@
          </service>
          -->
 
+        <!-- ==================== 阿里云EMAS配置 ==================== -->
+        <meta-data
+            android:name="com.alibaba.app.appkey"
+            android:value="335655908" />
+        <meta-data
+            android:name="com.alibaba.app.appsecret"
+            android:value="6d5086096f28435797413a48d932aff4" />
+
         <!-- ==================== 搜索元数据 ==================== -->
         <!-- 指定默认的搜索活动为NoteEditActivity -->
         <meta-data

src/Notesmaster/app/src/main/java/net/micode/notes/MainActivity.java

@@ -116,7 +116,14 @@ public class MainActivity extends AppCompatActivity implements SidebarFragment.O
     @Override
     public void onLoginSelected() {
         Log.d(TAG, "Login selected");
-        // TODO: 实现登录功能
+        Intent intent = new Intent(this, net.micode.notes.ui.LoginActivity.class);
+        startActivity(intent);
+    }
+
+    @Override
+    public void onLogoutSelected() {
+        Log.d(TAG, "Logout selected");
+        closeSidebar();
     }
 
     @Override

src/Notesmaster/app/src/main/java/net/micode/notes/NotesApplication.java

@@ -1,18 +1,32 @@
 package net.micode.notes;
 
 import android.app.Application;
+import android.util.Log;
+
+import net.micode.notes.auth.UserAuthManager;
 import net.micode.notes.data.ThemeRepository;
+import net.micode.notes.sync.SyncWorker;
+
 import com.google.android.material.color.DynamicColors;
 
 public class NotesApplication extends Application {
+    
+    private static final String TAG = "NotesApplication";
+
     @Override
     public void onCreate() {
         super.onCreate();
-        // Apply Dynamic Colors (Material You) if available
-        DynamicColors.applyToActivitiesIfAvailable(this);
         
-        // Apply saved theme preference
+        DynamicColors.applyToActivitiesIfAvailable(this);
+
         ThemeRepository repository = new ThemeRepository(this);
         ThemeRepository.applyTheme(repository.getThemeMode());
+
+        UserAuthManager authManager = UserAuthManager.getInstance(this);
+        authManager.initialize(this);
+        
+        Log.d(TAG, "EMAS Serverless initialized");
+
+        SyncWorker.initialize(this);
     }
 }

src/Notesmaster/app/src/main/java/net/micode/notes/api/AliyunConfig.java

@@ -0,0 +1,58 @@
+/*
+ * 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.api;
+
+import net.micode.notes.BuildConfig;
+
+/**
+ * 阿里云EMAS配置
+ * <p>
+ * 存储阿里云EMAS服务的配置信息，从BuildConfig读取（由local.properties生成）
+ * 敏感信息不再硬编码在源码中，避免泄露风险
+ * </p>
+ */
+public class AliyunConfig {
+
+    /**
+     * 阿里云EMAS AppKey (从BuildConfig读取)
+     */
+    public static final String APP_KEY = BuildConfig.ALIYUN_APP_KEY;
+
+    /**
+     * 阿里云EMAS AppSecret (从BuildConfig读取)
+     */
+    public static final String APP_SECRET = BuildConfig.ALIYUN_APP_SECRET;
+
+    /**
+     * 阿里云EMAS Serverless Space ID (从BuildConfig读取)
+     */
+    public static final String SPACE_ID = BuildConfig.ALIYUN_SPACE_ID;
+
+    /**
+     * 服务端点（EMAS Serverless HTTP触发器）(从BuildConfig读取)
+     */
+    public static final String ENDPOINT = BuildConfig.ALIYUN_ENDPOINT;
+
+    /**
+     * API基础路径
+     */
+    public static final String BASE_URL = ENDPOINT + "/api";
+
+    private AliyunConfig() {
+        // Utility class, prevent instantiation
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/api/AliyunService.java

@@ -0,0 +1,94 @@
+/*
+ * 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.api;
+
+import android.content.Context;
+import android.util.Log;
+
+import com.alibaba.sdk.android.push.CloudPushService;
+import com.alibaba.sdk.android.push.CommonCallback;
+import com.alibaba.sdk.android.push.noonesdk.PushServiceFactory;
+
+/**
+ * 阿里云服务管理类
+ * <p>
+ * 管理阿里云EMAS服务的初始化和配置，包括推送服务、云数据库等。
+ * </p>
+ */
+public class AliyunService {
+    
+    private static final String TAG = "AliyunService";
+    private static AliyunService sInstance;
+    private String mDeviceId;
+    
+    private AliyunService() {
+        // Private constructor for singleton
+    }
+    
+    /**
+     * 获取AliyunService单例实例
+     * 
+     * @return AliyunService实例
+     */
+    public static synchronized AliyunService getInstance() {
+        if (sInstance == null) {
+            sInstance = new AliyunService();
+        }
+        return sInstance;
+    }
+    
+    /**
+     * 初始化阿里云服务
+     * 
+     * @param context 应用上下文
+     */
+    public void initialize(Context context) {
+        Log.i(TAG, "Initializing AliyunService with AppKey: " + AliyunConfig.APP_KEY);
+        
+        try {
+            // Initialize push service
+            PushServiceFactory.init(context);
+            CloudPushService pushService = PushServiceFactory.getCloudPushService();
+            
+            pushService.register(context, AliyunConfig.APP_KEY, AliyunConfig.APP_SECRET, new CommonCallback() {
+                @Override
+                public void onSuccess(String response) {
+                    mDeviceId = pushService.getDeviceId();
+                    Log.i(TAG, "Alibaba Cloud Push SDK registered successfully");
+                    Log.i(TAG, "Device ID: " + mDeviceId);
+                }
+                
+                @Override
+                public void onFailed(String errorCode, String errorMessage) {
+                    Log.e(TAG, "Alibaba Cloud Push SDK registration failed: " + errorCode + " - " + errorMessage);
+                }
+            });
+            
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to initialize AliyunService", e);
+        }
+    }
+    
+    /**
+     * 获取设备ID
+     * 
+     * @return 设备ID
+     */
+    public String getDeviceId() {
+        return mDeviceId;
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/api/CloudCallback.java

@@ -0,0 +1,27 @@
+/*
+ * 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.api;
+
+/**
+ * 云数据库操作回调接口
+ *
+ * @param <T> 返回数据类型
+ */
+public interface CloudCallback<T> {
+    void onSuccess(T result);
+    void onError(String error);
+}

src/Notesmaster/app/src/main/java/net/micode/notes/api/CloudDatabaseHelper.java

@@ -0,0 +1,284 @@
+/*
+ * 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.api;
+
+import android.util.Log;
+
+import net.micode.notes.model.CloudNote;
+import net.micode.notes.model.WorkingNote;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import okhttp3.Call;
+import okhttp3.Callback;
+import okhttp3.MediaType;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.RequestBody;
+import okhttp3.Response;
+
+/**
+ * 云数据库帮助类（EMAS Serverless HTTP API版本）
+ * <p>
+ * 通过HTTP API与阿里云EMAS Serverless交互。
+ * </p>
+ */
+public class CloudDatabaseHelper {
+
+    private static final String TAG = "CloudDatabaseHelper";
+    private static final MediaType JSON = MediaType.get("application/json; charset=utf-8");
+    private static final String API_NOTES = AliyunConfig.BASE_URL + "/notes";
+
+    private String mUserId;
+    private String mDeviceId;
+    private String mAuthToken;
+    private OkHttpClient mHttpClient;
+
+    public CloudDatabaseHelper(String userId, String deviceId, String authToken) {
+        mUserId = userId;
+        mDeviceId = deviceId;
+        mAuthToken = authToken;
+        mHttpClient = new OkHttpClient.Builder()
+                .connectTimeout(10, TimeUnit.SECONDS)
+                .readTimeout(30, TimeUnit.SECONDS)
+                .writeTimeout(30, TimeUnit.SECONDS)
+                .addInterceptor(new RetryInterceptor())
+                .build();
+    }
+
+    /**
+     * 上传笔记到云端
+     */
+    public void uploadNote(WorkingNote note, CloudCallback<String> callback) {
+        Log.d(TAG, "Uploading note: " + note.getNoteId());
+
+        CloudNote cloudNote = new CloudNote(note, mDeviceId);
+        JSONObject json;
+        try {
+            json = cloudNote.toJson();
+            json.put("action", "upload");
+            json.put("userId", mUserId);
+        } catch (JSONException e) {
+            Log.e(TAG, "Failed to create JSON", e);
+            callback.onError("数据格式错误");
+            return;
+        }
+
+        RequestBody body = RequestBody.create(json.toString(), JSON);
+        Request request = new Request.Builder()
+                .url(API_NOTES)
+                .post(body)
+                .addHeader("Authorization", "Bearer " + mAuthToken)
+                .addHeader("Content-Type", "application/json")
+                .build();
+
+        mHttpClient.newCall(request).enqueue(new Callback() {
+            @Override
+            public void onFailure(Call call, IOException e) {
+                Log.e(TAG, "Upload failed", e);
+                callback.onError("网络错误: " + e.getMessage());
+            }
+
+            @Override
+            public void onResponse(Call call, Response response) throws IOException {
+                try {
+                    String responseBody = response.body().string();
+                    JSONObject jsonResponse = new JSONObject(responseBody);
+
+                    if (jsonResponse.getBoolean("success")) {
+                        String cloudId = jsonResponse.getString("cloudId");
+                        callback.onSuccess(cloudId);
+                    } else {
+                        String message = jsonResponse.optString("message", "上传失败");
+                        callback.onError(message);
+                    }
+                } catch (JSONException e) {
+                    Log.e(TAG, "Failed to parse response", e);
+                    callback.onError("解析响应失败");
+                } finally {
+                    response.close();
+                }
+            }
+        });
+    }
+
+    /**
+     * 从云端下载用户的所有笔记
+     */
+    public void downloadNotes(long lastSyncTime, CloudCallback<JSONArray> callback) {
+        Log.d(TAG, "Downloading notes for user: " + mUserId);
+
+        JSONObject json = new JSONObject();
+        try {
+            json.put("action", "download");
+            json.put("lastSyncTime", lastSyncTime);
+        } catch (JSONException e) {
+            Log.e(TAG, "Failed to create JSON", e);
+            callback.onError("数据格式错误");
+            return;
+        }
+
+        RequestBody body = RequestBody.create(json.toString(), JSON);
+        Request request = new Request.Builder()
+                .url(API_NOTES)
+                .post(body)
+                .addHeader("Authorization", "Bearer " + mAuthToken)
+                .addHeader("Content-Type", "application/json")
+                .build();
+
+        mHttpClient.newCall(request).enqueue(new Callback() {
+            @Override
+            public void onFailure(Call call, IOException e) {
+                Log.e(TAG, "Download failed", e);
+                callback.onError("网络错误: " + e.getMessage());
+            }
+
+            @Override
+            public void onResponse(Call call, Response response) throws IOException {
+                try {
+                    String responseBody = response.body().string();
+                    JSONObject jsonResponse = new JSONObject(responseBody);
+
+                    if (jsonResponse.getBoolean("success")) {
+                        JSONArray notesArray = jsonResponse.getJSONArray("notes");
+                        callback.onSuccess(notesArray);
+                    } else {
+                        String message = jsonResponse.optString("message", "下载失败");
+                        callback.onError(message);
+                    }
+                } catch (JSONException e) {
+                    Log.e(TAG, "Failed to parse response", e);
+                    callback.onError("解析响应失败");
+                } finally {
+                    response.close();
+                }
+            }
+        });
+    }
+
+    /**
+     * 删除云端笔记
+     */
+    public void deleteNote(String cloudNoteId, CloudCallback<Void> callback) {
+        Log.d(TAG, "Deleting note from cloud: " + cloudNoteId);
+
+        JSONObject json = new JSONObject();
+
+        try {
+            json.put("action", "delete");
+            json.put("cloudNoteId", cloudNoteId);
+            json.put("userId", mUserId);
+        } catch (JSONException e) {
+            Log.e(TAG, "Failed to create JSON", e);
+            callback.onError("数据格式错误");
+            return;
+        }
+
+        RequestBody body = RequestBody.create(json.toString(), JSON);
+        Request request = new Request.Builder()
+                .url(API_NOTES)
+                .post(body)
+                .addHeader("Authorization", "Bearer " + mAuthToken)
+                .addHeader("Content-Type", "application/json")
+                .build();
+
+        mHttpClient.newCall(request).enqueue(new Callback() {
+            @Override
+            public void onFailure(Call call, IOException e) {
+                Log.e(TAG, "Delete failed", e);
+                callback.onError("网络错误: " + e.getMessage());
+            }
+
+            @Override
+            public void onResponse(Call call, Response response) throws IOException {
+                try {
+                    String responseBody = response.body().string();
+                    JSONObject jsonResponse = new JSONObject(responseBody);
+
+                    if (jsonResponse.getBoolean("success")) {
+                        callback.onSuccess(null);
+                    } else {
+                        String message = jsonResponse.optString("message", "删除失败");
+                        callback.onError(message);
+                    }
+                } catch (JSONException e) {
+                    Log.e(TAG, "Failed to parse response", e);
+                    callback.onError("解析响应失败");
+                } finally {
+                    response.close();
+                }
+            }
+        });
+    }
+
+    /**
+     * 将笔记转换为云端数据格式
+     */
+    public Map<String, Object> convertToCloudData(WorkingNote note) {
+        Map<String, Object> data = new HashMap<>();
+        data.put("userId", mUserId);
+        data.put("deviceId", mDeviceId);
+        data.put("noteId", String.valueOf(note.getNoteId()));
+
+        // 如果没有title，从content提取第一行作为title
+        String title = note.getTitle();
+        String content = note.getContent();
+        if (title == null || title.trim().isEmpty()) {
+            title = extractFirstLine(content);
+        }
+
+        data.put("title", title);
+        data.put("content", content);
+        data.put("parentId", note.getFolderId());
+        data.put("modifiedTime", note.getModifiedDate());
+        data.put("syncStatus", 2);
+        data.put("lastSyncTime", System.currentTimeMillis());
+        return data;
+    }
+
+    /**
+     * 从文本中提取第一行作为标题
+     * 
+     * @param content 文本内容
+     * @return 第一行文本（最多50个字符）
+     */
+    private String extractFirstLine(String content) {
+        if (content == null || content.trim().isEmpty()) {
+            return "无标题";
+        }
+
+        // 按换行符分割，获取第一行
+        String firstLine = content.split("\\r?\\n")[0].trim();
+
+        // 限制长度，避免标题过长
+        int maxLength = 50;
+        if (firstLine.length() > maxLength) {
+            firstLine = firstLine.substring(0, maxLength) + "...";
+        }
+
+        return firstLine.isEmpty() ? "无标题" : firstLine;
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/api/RetryInterceptor.java

@@ -0,0 +1,110 @@
+/*
+ * 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.api;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+
+import okhttp3.Interceptor;
+import okhttp3.Request;
+import okhttp3.Response;
+
+/**
+ * OkHttp 重试拦截器
+ *
+ * <p>
+ * 实现指数退避重试策略，对网络超时和临时错误进行自动重试。
+ * 支持最多3次重试，每次重试间隔递增（1秒、2秒、4秒）。
+ * </p>
+ */
+public class RetryInterceptor implements Interceptor {
+
+    private static final String TAG = "RetryInterceptor";
+    private static final int MAX_RETRY_COUNT = 3;
+    private static final long INITIAL_RETRY_DELAY_MS = 1000;
+
+    @Override
+    public Response intercept(Chain chain) throws IOException {
+        Request request = chain.request();
+        Response response = null;
+        IOException exception = null;
+
+        for (int retryCount = 0; retryCount <= MAX_RETRY_COUNT; retryCount++) {
+            try {
+                response = chain.proceed(request);
+
+                // 如果响应成功，直接返回
+                if (response.isSuccessful()) {
+                    return response;
+                }
+
+                // 对于服务器错误 (5xx) 进行重试
+                if (response.code() >= 500 && response.code() < 600) {
+                    if (retryCount < MAX_RETRY_COUNT) {
+                        Log.w(TAG, "Server error " + response.code() + ", retrying... (" + (retryCount + 1) + "/" + MAX_RETRY_COUNT + ")");
+                        response.close();
+                        waitBeforeRetry(retryCount);
+                        continue;
+                    }
+                } else {
+                    // 客户端错误 (4xx) 不重试
+                    return response;
+                }
+            } catch (SocketTimeoutException | UnknownHostException e) {
+                // 网络超时和主机不可达时重试
+                exception = e;
+                if (retryCount < MAX_RETRY_COUNT) {
+                    Log.w(TAG, "Network error, retrying... (" + (retryCount + 1) + "/" + MAX_RETRY_COUNT + "): " + e.getMessage());
+                    waitBeforeRetry(retryCount);
+                } else {
+                    throw e;
+                }
+            } catch (IOException e) {
+                // 其他 IO 异常也尝试重试
+                exception = e;
+                if (retryCount < MAX_RETRY_COUNT) {
+                    Log.w(TAG, "IO error, retrying... (" + (retryCount + 1) + "/" + MAX_RETRY_COUNT + "): " + e.getMessage());
+                    waitBeforeRetry(retryCount);
+                } else {
+                    throw e;
+                }
+            }
+        }
+
+        // 如果所有重试都失败了
+        if (exception != null) {
+            throw exception;
+        }
+
+        return response;
+    }
+
+    /**
+     * 指数退避等待
+     */
+    private void waitBeforeRetry(int retryCount) {
+        long delay = INITIAL_RETRY_DELAY_MS * (1L << retryCount); // 1s, 2s, 4s
+        try {
+            Thread.sleep(delay);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/auth/AnonymousAuthManager.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.auth;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.provider.Settings;
+import android.util.Log;
+
+import java.util.UUID;
+
+/**
+ * 匿名认证管理器
+ * <p>
+ * 管理匿名用户的认证信息，包括生成和存储用户ID、设备ID等。
+ * 使用单例模式确保全局只有一个认证管理器实例。
+ * </p>
+ */
+public class AnonymousAuthManager {
+
+    private static final String TAG = "AnonymousAuthManager";
+    private static final String PREFS_NAME = "AnonymousAuth";
+    private static final String KEY_USER_ID = "anonymous_user_id";
+    private static final String KEY_DEVICE_ID = "device_id";
+
+    private static AnonymousAuthManager sInstance;
+    private SharedPreferences mPrefs;
+    private String mUserId;
+    private String mDeviceId;
+
+    private AnonymousAuthManager(Context context) {
+        mPrefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
+    }
+
+    /**
+     * 获取AnonymousAuthManager单例实例
+     *
+     * @param context 应用上下文
+     * @return AnonymousAuthManager实例
+     */
+    public static synchronized AnonymousAuthManager getInstance(Context context) {
+        if (sInstance == null) {
+            sInstance = new AnonymousAuthManager(context.getApplicationContext());
+        }
+        return sInstance;
+    }
+
+    /**
+     * 初始化认证管理器
+     *
+     * @param context 应用上下文
+     */
+    public void initialize(Context context) {
+        if (mUserId == null) {
+            mUserId = mPrefs.getString(KEY_USER_ID, null);
+            if (mUserId == null) {
+                mUserId = generateAnonymousUserId();
+                mPrefs.edit().putString(KEY_USER_ID, mUserId).apply();
+                Log.i(TAG, "Generated new anonymous user ID");
+            }
+        }
+
+        if (mDeviceId == null) {
+            mDeviceId = mPrefs.getString(KEY_DEVICE_ID, null);
+            if (mDeviceId == null) {
+                mDeviceId = generateDeviceId(context);
+                mPrefs.edit().putString(KEY_DEVICE_ID, mDeviceId).apply();
+                Log.i(TAG, "Generated new device ID");
+            }
+        }
+
+        Log.i(TAG, "AnonymousAuthManager initialized successfully");
+    }
+
+    /**
+     * 获取用户ID
+     *
+     * @return 用户ID
+     */
+    public String getUserId() {
+        return mUserId;
+    }
+
+    /**
+     * 获取设备ID
+     *
+     * @return 设备ID
+     */
+    public String getDeviceId() {
+        return mDeviceId;
+    }
+
+    /**
+     * 生成匿名用户ID
+     *
+     * @return 格式为 anon_xxx 的用户ID
+     */
+    private String generateAnonymousUserId() {
+        return "anon_" + UUID.randomUUID().toString().replace("-", "");
+    }
+
+    /**
+     * 生成设备ID
+     *
+     * @param context 应用上下文
+     * @return 设备ID
+     */
+    private String generateDeviceId(Context context) {
+        String androidId = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
+        if (androidId == null || androidId.isEmpty()) {
+            androidId = UUID.randomUUID().toString();
+        }
+        return "device_" + androidId;
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/auth/UserAuthManager.java

@@ -0,0 +1,473 @@
+/*
+ * 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.auth;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.util.Log;
+
+import androidx.annotation.Nullable;
+
+import net.micode.notes.api.AliyunConfig;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.IOException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import okhttp3.Call;
+import okhttp3.Callback;
+import okhttp3.MediaType;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.RequestBody;
+import okhttp3.Response;
+
+/**
+ * 用户认证管理器（阿里云EMAS Serverless HTTP API版本）
+ * <p>
+ * 使用阿里云EMAS Serverless的HTTP API进行用户认证。
+ * 需要先登录阿里云控制台创建EMAS应用并开通Serverless服务。
+ * </p>
+ */
+public class UserAuthManager {
+
+    private static final String TAG = "UserAuthManager";
+    private static final String PREFS_NAME = "UserAuth";
+    private static final String KEY_USER_ID = "user_id";
+    private static final String KEY_USERNAME = "username";
+    private static final String KEY_AUTH_TOKEN = "auth_token";
+    private static final String KEY_REFRESH_TOKEN = "refresh_token";
+    private static final String KEY_IS_LOGGED_IN = "is_logged_in";
+    private static final String KEY_DEVICE_ID = "device_id";
+    private static final String KEY_TOKEN_EXPIRE_TIME = "token_expire_time";
+
+    // Token过期时间：7天
+    private static final long TOKEN_EXPIRE_DURATION = 7 * 24 * 60 * 60 * 1000;
+
+    // EMAS Serverless API地址
+    private static final String BASE_URL = AliyunConfig.BASE_URL;
+    private static final String API_AUTH = BASE_URL + "/auth";
+    private static final String API_REFRESH_TOKEN = BASE_URL + "/auth/refresh";
+    private static final MediaType JSON = MediaType.get("application/json; charset=utf-8");
+
+    private static UserAuthManager sInstance;
+    private final ExecutorService mExecutor;
+    private final OkHttpClient mHttpClient;
+    private SharedPreferences mPrefs;
+    private Context mContext;
+
+    private String mUserId;
+    private String mUsername;
+    private String mAuthToken;
+    private String mRefreshToken;
+    private String mDeviceId;
+    private boolean mIsLoggedIn;
+    private long mTokenExpireTime;
+
+    private UserAuthManager(Context context) {
+        mContext = context.getApplicationContext();
+        mPrefs = mContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
+        mExecutor = Executors.newSingleThreadExecutor();
+        mHttpClient = new OkHttpClient.Builder()
+                .connectTimeout(10, java.util.concurrent.TimeUnit.SECONDS)
+                .readTimeout(30, java.util.concurrent.TimeUnit.SECONDS)
+                .writeTimeout(30, java.util.concurrent.TimeUnit.SECONDS)
+                .addInterceptor(new net.micode.notes.api.RetryInterceptor())
+                .build();
+        loadUserInfo();
+    }
+
+    public static synchronized UserAuthManager getInstance(Context context) {
+        if (sInstance == null) {
+            sInstance = new UserAuthManager(context);
+        }
+        return sInstance;
+    }
+
+    /**
+     * 初始化（配置EMAS Serverless）
+     */
+    public void initialize(Context context) {
+        Log.d(TAG, "Initializing UserAuthManager");
+        Log.d(TAG, "AppKey: " + AliyunConfig.APP_KEY);
+        // 这里可以添加EMAS SDK初始化（如果需要）
+    }
+
+    /**
+     * 认证回调接口
+     */
+    public interface AuthCallback {
+        void onSuccess(String userId, String username);
+        void onError(String error);
+    }
+
+    /**
+     * 加载本地存储的用户信息
+     */
+    private void loadUserInfo() {
+        mIsLoggedIn = mPrefs.getBoolean(KEY_IS_LOGGED_IN, false);
+        mUserId = mPrefs.getString(KEY_USER_ID, null);
+        mUsername = mPrefs.getString(KEY_USERNAME, null);
+        mAuthToken = mPrefs.getString(KEY_AUTH_TOKEN, null);
+        mRefreshToken = mPrefs.getString(KEY_REFRESH_TOKEN, null);
+        mTokenExpireTime = mPrefs.getLong(KEY_TOKEN_EXPIRE_TIME, 0);
+        mDeviceId = mPrefs.getString(KEY_DEVICE_ID, null);
+
+        if (mDeviceId == null) {
+            mDeviceId = generateDeviceId();
+            mPrefs.edit().putString(KEY_DEVICE_ID, mDeviceId).apply();
+        }
+
+        Log.d(TAG, "User info loaded, logged in: " + mIsLoggedIn);
+    }
+
+    /**
+     * 用户注册
+     */
+    public void register(String username, String password, AuthCallback callback) {
+        if (username == null || username.isEmpty() || password == null || password.isEmpty()) {
+            callback.onError("用户名和密码不能为空");
+            return;
+        }
+
+        mExecutor.execute(() -> {
+            try {
+                String hashedPassword = hashPassword(password);
+
+                // 构建JSON请求体
+                JSONObject json = new JSONObject();
+                json.put("action", "register");
+                json.put("username", username);
+                json.put("password", hashedPassword);
+                json.put("deviceId", mDeviceId);
+                json.put("appKey", AliyunConfig.APP_KEY);
+
+                RequestBody body = RequestBody.create(json.toString(), JSON);
+                Request request = new Request.Builder()
+                        .url(API_AUTH)
+                        .post(body)
+                        .build();
+
+                mHttpClient.newCall(request).enqueue(new Callback() {
+                    @Override
+                    public void onFailure(Call call, IOException e) {
+                        Log.e(TAG, "Register failed", e);
+                        callback.onError("网络错误: " + e.getMessage());
+                    }
+
+                    @Override
+                    public void onResponse(Call call, Response response) throws IOException {
+                        handleAuthResponse(response, username, callback);
+                    }
+                });
+            } catch (Exception e) {
+                Log.e(TAG, "Register error", e);
+                callback.onError("注册失败: " + e.getMessage());
+            }
+        });
+    }
+
+    /**
+     * 用户登录
+     */
+    public void login(String username, String password, AuthCallback callback) {
+        if (username == null || username.isEmpty() || password == null || password.isEmpty()) {
+            callback.onError("用户名和密码不能为空");
+            return;
+        }
+
+        mExecutor.execute(() -> {
+            try {
+                String hashedPassword = hashPassword(password);
+
+                // 构建JSON请求体
+                JSONObject json = new JSONObject();
+                json.put("action", "login");
+                json.put("username", username);
+                json.put("password", hashedPassword);
+                json.put("deviceId", mDeviceId);
+                json.put("appKey", AliyunConfig.APP_KEY);
+
+                RequestBody body = RequestBody.create(json.toString(), JSON);
+                Request request = new Request.Builder()
+                        .url(API_AUTH)
+                        .post(body)
+                        .build();
+
+                mHttpClient.newCall(request).enqueue(new Callback() {
+                    @Override
+                    public void onFailure(Call call, IOException e) {
+                        Log.e(TAG, "Login failed", e);
+                        callback.onError("网络错误: " + e.getMessage());
+                    }
+
+                    @Override
+                    public void onResponse(Call call, Response response) throws IOException {
+                        handleAuthResponse(response, username, callback);
+                    }
+                });
+            } catch (Exception e) {
+                Log.e(TAG, "Login error", e);
+                callback.onError("登录失败: " + e.getMessage());
+            }
+        });
+    }
+
+    /**
+     * 处理认证响应
+     */
+    private void handleAuthResponse(Response response, String username, AuthCallback callback) {
+        String responseBody = null;
+        try {
+            if (!response.isSuccessful()) {
+                String errorBody = response.body() != null ? response.body().string() : "Unknown error";
+                callback.onError("服务器错误: " + response.code() + " - " + errorBody);
+                return;
+            }
+
+            responseBody = response.body().string();
+            JSONObject json = new JSONObject(responseBody);
+
+            if (json.getBoolean("success")) {
+                mUserId = json.getString("userId");
+                // 支持两种字段名：token 或 authToken
+                if (json.has("token")) {
+                    mAuthToken = json.getString("token");
+                } else if (json.has("authToken")) {
+                    mAuthToken = json.getString("authToken");
+                }
+                if (json.has("refreshToken")) {
+                    mRefreshToken = json.getString("refreshToken");
+                }
+                mTokenExpireTime = System.currentTimeMillis() + TOKEN_EXPIRE_DURATION;
+                mUsername = username;
+                mIsLoggedIn = true;
+
+                saveUserInfo();
+
+                callback.onSuccess(mUserId, mUsername);
+            } else {
+                callback.onError(json.getString("message"));
+            }
+        } catch (JSONException | IOException e) {
+            Log.e(TAG, "Parse response error", e);
+            callback.onError("解析响应失败");
+        } finally {
+            response.close();
+        }
+    }
+
+    /**
+     * 保存用户信息到本地
+     */
+    private void saveUserInfo() {
+        mPrefs.edit()
+                .putBoolean(KEY_IS_LOGGED_IN, mIsLoggedIn)
+                .putString(KEY_USER_ID, mUserId)
+                .putString(KEY_USERNAME, mUsername)
+                .putString(KEY_AUTH_TOKEN, mAuthToken)
+                .putString(KEY_REFRESH_TOKEN, mRefreshToken)
+                .putLong(KEY_TOKEN_EXPIRE_TIME, mTokenExpireTime)
+                .putString(KEY_DEVICE_ID, mDeviceId)
+                .apply();
+    }
+
+    /**
+     * 登出
+     */
+    public void logout() {
+        mIsLoggedIn = false;
+        mUserId = null;
+        mUsername = null;
+        mAuthToken = null;
+        mRefreshToken = null;
+        mTokenExpireTime = 0;
+
+        mPrefs.edit()
+                .putBoolean(KEY_IS_LOGGED_IN, false)
+                .remove(KEY_USER_ID)
+                .remove(KEY_USERNAME)
+                .remove(KEY_AUTH_TOKEN)
+                .remove(KEY_REFRESH_TOKEN)
+                .remove(KEY_TOKEN_EXPIRE_TIME)
+                .apply();
+
+        Log.i(TAG, "User logged out");
+    }
+
+    /**
+     * 密码哈希（使用SHA-256）
+     *
+     * @throws RuntimeException 如果SHA-256算法不可用
+     */
+    private String hashPassword(String password) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] hash = digest.digest(password.getBytes(java.nio.charset.StandardCharsets.UTF_8));
+            StringBuilder hexString = new StringBuilder();
+            for (byte b : hash) {
+                String hex = Integer.toHexString(0xff & b);
+                if (hex.length() == 1) hexString.append('0');
+                hexString.append(hex);
+            }
+            return hexString.toString();
+        } catch (NoSuchAlgorithmException e) {
+            Log.e(TAG, "Hash algorithm not found", e);
+            throw new RuntimeException("密码哈希失败：系统不支持SHA-256算法", e);
+        }
+    }
+
+    /**
+     * 生成设备ID
+     */
+    private String generateDeviceId() {
+        return "device_" + java.util.UUID.randomUUID().toString().replace("-", "").substring(0, 16);
+    }
+
+    // ==================== Getter Methods ====================
+
+    public boolean isLoggedIn() {
+        return mIsLoggedIn;
+    }
+
+    @Nullable
+    public String getUserId() {
+        return mUserId;
+    }
+
+    @Nullable
+    public String getUsername() {
+        return mUsername;
+    }
+
+    @Nullable
+    public String getAuthToken() {
+        return mAuthToken;
+    }
+
+    public String getDeviceId() {
+        return mDeviceId;
+    }
+
+    @Nullable
+    public String getRefreshToken() {
+        return mRefreshToken;
+    }
+
+    /**
+     * 检查Token是否即将过期（24小时内）
+     */
+    public boolean isTokenExpiringSoon() {
+        if (!mIsLoggedIn || mTokenExpireTime == 0) {
+            return false;
+        }
+        long timeUntilExpire = mTokenExpireTime - System.currentTimeMillis();
+        return timeUntilExpire < 24 * 60 * 60 * 1000; // 24小时内过期
+    }
+
+    /**
+     * 检查Token是否已过期
+     */
+    public boolean isTokenExpired() {
+        if (!mIsLoggedIn || mTokenExpireTime == 0) {
+            return false;
+        }
+        return System.currentTimeMillis() >= mTokenExpireTime;
+    }
+
+    /**
+     * 刷新Token
+     *
+     * @param callback 刷新回调
+     */
+    public void refreshToken(TokenRefreshCallback callback) {
+        if (mRefreshToken == null) {
+            callback.onError("没有可用的刷新令牌");
+            return;
+        }
+
+        mExecutor.execute(() -> {
+            try {
+                JSONObject json = new JSONObject();
+                json.put("action", "refresh");
+                json.put("refreshToken", mRefreshToken);
+                json.put("deviceId", mDeviceId);
+
+                RequestBody body = RequestBody.create(json.toString(), JSON);
+                Request request = new Request.Builder()
+                        .url(API_REFRESH_TOKEN)
+                        .post(body)
+                        .build();
+
+                mHttpClient.newCall(request).enqueue(new Callback() {
+                    @Override
+                    public void onFailure(Call call, IOException e) {
+                        Log.e(TAG, "Token refresh failed", e);
+                        callback.onError("网络错误: " + e.getMessage());
+                    }
+
+                    @Override
+                    public void onResponse(Call call, Response response) throws IOException {
+                        String responseBody = null;
+                        try {
+                            if (!response.isSuccessful()) {
+                                callback.onError("服务器错误: " + response.code());
+                                return;
+                            }
+
+                            responseBody = response.body().string();
+                            JSONObject json = new JSONObject(responseBody);
+
+                            if (json.getBoolean("success")) {
+                                mAuthToken = json.getString("token");
+                                if (json.has("refreshToken")) {
+                                    mRefreshToken = json.getString("refreshToken");
+                                }
+                                mTokenExpireTime = System.currentTimeMillis() + TOKEN_EXPIRE_DURATION;
+                                saveUserInfo();
+                                callback.onSuccess(mAuthToken);
+                            } else {
+                                callback.onError(json.getString("message"));
+                            }
+                        } catch (JSONException e) {
+                            Log.e(TAG, "Parse refresh response error", e);
+                            callback.onError("解析响应失败");
+                        } finally {
+                            response.close();
+                        }
+                    }
+                });
+            } catch (Exception e) {
+                Log.e(TAG, "Refresh token error", e);
+                callback.onError("刷新失败: " + e.getMessage());
+            }
+        });
+    }
+
+    /**
+     * Token刷新回调接口
+     */
+    public interface TokenRefreshCallback {
+        void onSuccess(String newToken);
+        void onError(String error);
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/data/Notes.java

@@ -285,6 +285,36 @@ public class Notes {
          * <P> Type : INTEGER (long) </P>
          */
         public static final String GTASK_FINISHED_TIME = "gtask_finished_time";
+
+        /**
+         * Cloud User ID for sync
+         * <P> Type : TEXT </P>
+         */
+        public static final String CLOUD_USER_ID = "cloud_user_id";
+
+        /**
+         * Cloud Device ID for sync
+         * <P> Type : TEXT </P>
+         */
+        public static final String CLOUD_DEVICE_ID = "cloud_device_id";
+
+        /**
+         * Sync Status: 0=Not synced, 1=Syncing, 2=Synced, 3=Conflict
+         * <P> Type : INTEGER </P>
+         */
+        public static final String SYNC_STATUS = "sync_status";
+
+        /**
+         * Last Sync Time (Timestamp)
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String LAST_SYNC_TIME = "last_sync_time";
+
+        /**
+         * Cloud Note ID for sync (UUID)
+         * <P> Type : TEXT </P>
+         */
+        public static final String CLOUD_NOTE_ID = "cloud_note_id";
     }
 
     public interface DataColumns {

src/Notesmaster/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java

@@ -66,11 +66,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
     /**
      * 数据库版本号
      * <p>
-     * 当前数据库版本为8，用于跟踪数据库结构变更。
+     * 当前数据库版本为12，用于跟踪数据库结构变更。
      * 当数据库版本变更时，onUpgrade方法会被调用以执行升级逻辑。
      * </p>
      */
-    private static final int DB_VERSION = 10;
+    private static final int DB_VERSION = 13;
 
     /**
      * 数据库表名常量接口
@@ -156,7 +156,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0," +
             NoteColumns.TOP + " INTEGER NOT NULL DEFAULT 0," +
             NoteColumns.LOCKED + " INTEGER NOT NULL DEFAULT 0," +
-            NoteColumns.TITLE + " TEXT NOT NULL DEFAULT ''" +
+            NoteColumns.TITLE + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.CLOUD_USER_ID + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.CLOUD_DEVICE_ID + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.SYNC_STATUS + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.LAST_SYNC_TIME + " INTEGER NOT NULL DEFAULT 0" +
         ")";
 
     /**
@@ -578,6 +582,24 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
             oldVersion++;
         }
 
+        // 从V10升级到V11
+        if (oldVersion == 10) {
+            upgradeToV11(db);
+            oldVersion++;
+        }
+
+        // 从V11升级到V12
+        if (oldVersion == 11) {
+            upgradeToV12(db);
+            oldVersion++;
+        }
+
+        // 从V12升级到V13
+        if (oldVersion == 12) {
+            upgradeToV13(db);
+            oldVersion++;
+        }
+
         // 如果需要，重新创建触发器
         if (reCreateTriggers) {
             reCreateNoteTableTriggers(db);
@@ -674,13 +696,32 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
                  }
             }
             
-            if (cursor != null) {
-                cursor.close();
-            }
-        } catch (Exception e) {
-            Log.e(TAG, "Failed to fix database in onOpen", e);
-        }
-    }
+             boolean hasCloudNoteIdColumn = false;
+             if (cursor != null) {
+                 if (cursor.getColumnIndex(NoteColumns.CLOUD_NOTE_ID) != -1) {
+                     hasCloudNoteIdColumn = true;
+                 }
+             }
+
+             if (!hasCloudNoteIdColumn) {
+                 try {
+                     db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.CLOUD_NOTE_ID
+                             + " TEXT NOT NULL DEFAULT ''");
+                     db.execSQL("CREATE INDEX IF NOT EXISTS idx_cloud_note_id ON " + TABLE.NOTE
+                             + "(" + NoteColumns.CLOUD_NOTE_ID + ")");
+                     Log.i(TAG, "Fixed: Added missing CLOUD_NOTE_ID column and index in onOpen");
+                 } catch (Exception e) {
+                     Log.e(TAG, "Failed to add CLOUD_NOTE_ID column in onOpen", e);
+                 }
+             }
+
+             if (cursor != null) {
+                 cursor.close();
+             }
+         } catch (Exception e) {
+             Log.e(TAG, "Failed to fix database in onOpen", e);
+         }
+     }
 
     /**
      * 升级数据库到V2版本
@@ -840,6 +881,86 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         createPresetTemplates(db);
     }
 
+    /**
+     * 升级数据库到V11版本
+     * <p>
+     * 添加云同步相关列：CLOUD_USER_ID, CLOUD_DEVICE_ID, SYNC_STATUS, LAST_SYNC_TIME
+     * </p>
+     *
+     * @param db SQLiteDatabase实例
+     */
+    private void upgradeToV11(SQLiteDatabase db) {
+        try {
+            db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.CLOUD_USER_ID
+                    + " TEXT NOT NULL DEFAULT ''");
+            db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.CLOUD_DEVICE_ID
+                    + " TEXT NOT NULL DEFAULT ''");
+            db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.SYNC_STATUS
+                    + " INTEGER NOT NULL DEFAULT 0");
+            db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.LAST_SYNC_TIME
+                    + " INTEGER NOT NULL DEFAULT 0");
+            Log.i(TAG, "Upgraded database to V11: Added cloud sync columns");
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to add cloud sync columns in V11 upgrade", e);
+        }
+    }
+
+    /**
+     * 升级数据库到V12版本
+     * <p>
+     * 添加cloud_note_id列用于云端笔记唯一标识
+     * </p>
+     *
+     * @param db SQLiteDatabase实例
+     */
+    private void upgradeToV12(SQLiteDatabase db) {
+        try {
+            db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.CLOUD_NOTE_ID
+                    + " TEXT NOT NULL DEFAULT ''");
+            db.execSQL("CREATE INDEX IF NOT EXISTS idx_cloud_note_id ON " + TABLE.NOTE
+                    + "(" + NoteColumns.CLOUD_NOTE_ID + ")");
+            Log.i(TAG, "Upgraded database to V12: Added cloud_note_id column and index");
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to add cloud_note_id column in V12 upgrade", e);
+        }
+    }
+
+    /**
+     * 升级数据库到V13版本
+     * <p>
+     * 数据迁移：修复文件夹title为空的问题
+     * 将所有title为空的文件夹的title字段设置为snippet的值
+     * </p>
+     *
+     * @param db SQLiteDatabase实例
+     */
+    private void upgradeToV13(SQLiteDatabase db) {
+        try {
+            String sql = "UPDATE " + TABLE.NOTE
+                    + " SET " + NoteColumns.TITLE + " = " + NoteColumns.SNIPPET
+                    + " WHERE " + NoteColumns.TYPE + " = " + Notes.TYPE_FOLDER
+                    + " AND (" + NoteColumns.TITLE + " IS NULL OR " + NoteColumns.TITLE + " = '')";
+            db.execSQL(sql);
+
+            android.database.Cursor cursor = db.rawQuery(
+                    "SELECT COUNT(*) FROM " + TABLE.NOTE
+                            + " WHERE " + NoteColumns.TYPE + " = " + Notes.TYPE_FOLDER
+                            + " AND (" + NoteColumns.TITLE + " IS NOT NULL OR " + NoteColumns.TITLE + " != '')",
+                    null);
+            if (cursor != null) {
+                if (cursor.moveToFirst()) {
+                    int count = cursor.getInt(0);
+                    Log.i(TAG, "Upgraded database to V13: Migrated " + count + " folders with non-empty title");
+                }
+                cursor.close();
+            }
+
+            Log.i(TAG, "Successfully upgraded database to V13: Fixed folder title migration");
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to migrate folder titles in V13 upgrade", e);
+        }
+    }
+
     /**
      * 创建模板系统文件夹
      *
@@ -884,6 +1005,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
         values.put(NoteColumns.PARENT_ID, parentId);
         values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
         values.put(NoteColumns.SNIPPET, name);
+        values.put(NoteColumns.TITLE, name);
         values.put(NoteColumns.CREATED_DATE, System.currentTimeMillis());
         values.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis());
         values.put(NoteColumns.NOTES_COUNT, 0);

src/Notesmaster/app/src/main/java/net/micode/notes/data/NotesRepository.java

@@ -30,6 +30,8 @@ import net.micode.notes.data.Notes.DataColumns;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.data.Notes.TextNote;
 import net.micode.notes.model.Note;
+import net.micode.notes.model.WorkingNote;
+import net.micode.notes.sync.SyncConstants;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -90,6 +92,7 @@ public class NotesRepository {
 
     private final ContentResolver contentResolver;
     private final ExecutorService executor;
+    private final Context context;
 
     // 选择条件常量
     private static final String NORMAL_SELECTION = NoteColumns.PARENT_ID + " = ?";
@@ -195,6 +198,15 @@ public class NotesRepository {
      */
     public NotesRepository(ContentResolver contentResolver) {
         this.contentResolver = contentResolver;
+        this.context = null;
+        // 使用单线程Executor确保数据访问的顺序性
+        this.executor = java.util.concurrent.Executors.newSingleThreadExecutor();
+        Log.d(TAG, "NotesRepository initialized");
+    }
+
+    public NotesRepository(Context context) {
+        this.context = context.getApplicationContext();
+        this.contentResolver = context.getContentResolver();
         // 使用单线程Executor确保数据访问的顺序性
         this.executor = java.util.concurrent.Executors.newSingleThreadExecutor();
         Log.d(TAG, "NotesRepository initialized");
@@ -444,6 +456,7 @@ public class NotesRepository {
                 values.put(NoteColumns.PARENT_ID, parentId);
                 values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
                 values.put(NoteColumns.SNIPPET, name);
+                values.put(NoteColumns.TITLE, name);
                 values.put(NoteColumns.CREATED_DATE, currentTime);
                 values.put(NoteColumns.MODIFIED_DATE, currentTime);
                 values.put(NoteColumns.LOCAL_MODIFIED, 1);
@@ -1358,4 +1371,499 @@ public class NotesRepository {
         }
         return title;
     }
+
+    // ==================== Cloud Sync Methods ====================
+
+    /**
+     * 获取未同步的笔记列表
+     * <p>
+     * 查询所有 LOCAL_MODIFIED = 1 的笔记
+     * </p>
+     *
+     * @param callback 回调接口，返回未同步笔记列表
+     */
+    public void getUnsyncedNotes(Callback<List<NoteInfo>> callback) {
+        executor.execute(() -> {
+            try {
+                String selection = NoteColumns.LOCAL_MODIFIED + " = ?";
+                String[] selectionArgs = {"1"};
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    NoteColumns.MODIFIED_DATE + " DESC"
+                );
+
+                List<NoteInfo> notes = new ArrayList<>();
+                if (cursor != null) {
+                    try {
+                        while (cursor.moveToNext()) {
+                            notes.add(noteFromCursor(cursor));
+                        }
+                        Log.d(TAG, "Found " + notes.size() + " unsynced notes");
+                    } finally {
+                        cursor.close();
+                    }
+                }
+
+                callback.onSuccess(notes);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to get unsynced notes", e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 标记笔记为已同步
+     * <p>
+     * 更新 LOCAL_MODIFIED = 0 和 SYNC_STATUS = 2
+     * </p>
+     *
+     * @param noteId 笔记ID
+     */
+    public void markAsSynced(long noteId) {
+        executor.execute(() -> {
+            try {
+                ContentValues values = new ContentValues();
+                values.put(NoteColumns.LOCAL_MODIFIED, 0);
+                values.put(NoteColumns.SYNC_STATUS, 2);
+                values.put(NoteColumns.LAST_SYNC_TIME, System.currentTimeMillis());
+
+                Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                int rows = contentResolver.update(uri, values, null, null);
+
+                if (rows > 0) {
+                    Log.d(TAG, "Marked note as synced: " + noteId);
+                }
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to mark note as synced: " + noteId, e);
+            }
+        });
+    }
+
+    /**
+     * 更新笔记同步状态
+     *
+     * @param noteId 笔记ID
+     * @param status 同步状态 (0=未同步, 1=同步中, 2=已同步, 3=冲突)
+     */
+    public void updateSyncStatus(long noteId, int status) {
+        executor.execute(() -> {
+            try {
+                ContentValues values = new ContentValues();
+                values.put(NoteColumns.SYNC_STATUS, status);
+
+                Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                int rows = contentResolver.update(uri, values, null, null);
+
+                if (rows > 0) {
+                    Log.d(TAG, "Updated sync status for note " + noteId + " to " + status);
+                }
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to update sync status: " + noteId, e);
+            }
+        });
+    }
+
+    /**
+     * 获取最后同步时间
+     *
+     * @param callback 回调接口，返回最后同步时间（毫秒）
+     */
+    public void getLastSyncTime(Callback<Long> callback) {
+        executor.execute(() -> {
+            try {
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    new String[]{"MAX(" + NoteColumns.LAST_SYNC_TIME + ") AS last_sync"},
+                    null,
+                    null,
+                    null
+                );
+
+                long lastSyncTime = 0;
+                if (cursor != null) {
+                    try {
+                        if (cursor.moveToFirst()) {
+                            lastSyncTime = cursor.getLong(0);
+                        }
+                    } finally {
+                        cursor.close();
+                    }
+                }
+
+                callback.onSuccess(lastSyncTime);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to get last sync time", e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    // ==================== 云同步相关方法 ====================
+
+    /**
+     * 查询所有本地修改过的笔记（LOCAL_MODIFIED = 1）
+     * <p>
+     * 根据当前登录用户过滤，只返回该用户的笔记
+     * </p>
+     *
+     * @param cloudUserId 当前用户的云端ID
+     * @param callback 回调接口，返回本地修改过的笔记列表
+     */
+    public void getLocalModifiedNotes(String cloudUserId, Callback<List<WorkingNote>> callback) {
+        executor.execute(() -> {
+            try {
+                // 同时过滤 LOCAL_MODIFIED = 1 和 cloud_user_id = 当前用户
+                String selection = NoteColumns.LOCAL_MODIFIED + " = ? AND " + NoteColumns.CLOUD_USER_ID + " = ?";
+                String[] selectionArgs = new String[] { "1", cloudUserId };
+                String sortOrder = NoteColumns.MODIFIED_DATE + " DESC";
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    sortOrder
+                );
+
+                List<WorkingNote> notes = new ArrayList<>();
+                if (cursor != null) {
+                    while (cursor.moveToNext()) {
+                        long id = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+                        WorkingNote note = WorkingNote.load(context, id);
+                        notes.add(note);
+                    }
+                    cursor.close();
+                }
+
+                Log.d(TAG, "Found " + notes.size() + " locally modified notes for user: " + cloudUserId);
+                callback.onSuccess(notes);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to get local modified notes for user: " + cloudUserId, e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 查询所有本地修改过的笔记（LOCAL_MODIFIED = 1）- 不过滤用户（向后兼容）
+     *
+     * @param callback 回调接口，返回本地修改过的笔记列表
+     * @deprecated 请使用 {@link #getLocalModifiedNotes(String, Callback)}
+     */
+    @Deprecated
+    public void getLocalModifiedNotes(Callback<List<WorkingNote>> callback) {
+        executor.execute(() -> {
+            try {
+                String selection = NoteColumns.LOCAL_MODIFIED + " = ?";
+                String[] selectionArgs = new String[] { "1" };
+                String sortOrder = NoteColumns.MODIFIED_DATE + " DESC";
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    sortOrder
+                );
+
+                List<WorkingNote> notes = new ArrayList<>();
+                if (cursor != null) {
+                    while (cursor.moveToNext()) {
+                        long id = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+                        WorkingNote note = WorkingNote.load(context, id);
+                        notes.add(note);
+                    }
+                    cursor.close();
+                }
+
+                Log.d(TAG, "Found " + notes.size() + " locally modified notes");
+                callback.onSuccess(notes);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to get local modified notes", e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 标记笔记为已同步
+     * 更新: LOCAL_MODIFIED=0, SYNC_STATUS=2, LAST_SYNC_TIME=now
+     *
+     * @param noteId 笔记ID
+     * @param callback 回调接口
+     */
+    public void markNoteSynced(long noteId, Callback<Void> callback) {
+        executor.execute(() -> {
+            try {
+                ContentValues values = new ContentValues();
+                values.put(NoteColumns.LOCAL_MODIFIED, 0);
+                values.put(NoteColumns.SYNC_STATUS, SyncConstants.SYNC_STATUS_SYNCED);
+                values.put(NoteColumns.LAST_SYNC_TIME, System.currentTimeMillis());
+
+                Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                int rows = contentResolver.update(uri, values, null, null);
+
+                if (rows > 0) {
+                    Log.d(TAG, "Marked note " + noteId + " as synced");
+                }
+
+                callback.onSuccess(null);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to mark note as synced: " + noteId, e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 根据noteId查找笔记
+     *
+     * @param noteId 笔记ID（字符串形式）
+     * @param callback 回调接口，返回找到的笔记或null
+     */
+    public void findNoteByNoteId(String noteId, Callback<WorkingNote> callback) {
+        executor.execute(() -> {
+            try {
+                long id = Long.parseLong(noteId);
+                Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id);
+
+                Cursor cursor = contentResolver.query(
+                    uri,
+                    null,
+                    null,
+                    null,
+                    null
+                );
+
+                WorkingNote note = null;
+                if (cursor != null && cursor.moveToFirst()) {
+                    long noteIdFromCursor = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+                    note = WorkingNote.load(context, noteIdFromCursor);
+                    cursor.close();
+                }
+
+                callback.onSuccess(note);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to find note by noteId: " + noteId, e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 根据cloudNoteId查找笔记
+     *
+     * @param cloudNoteId 云端笔记ID（UUID）
+     * @param callback 回调接口，返回找到的笔记或null
+     */
+    public void findByCloudNoteId(String cloudNoteId, Callback<WorkingNote> callback) {
+        executor.execute(() -> {
+            try {
+                if (cloudNoteId == null || cloudNoteId.isEmpty()) {
+                    callback.onSuccess(null);
+                    return;
+                }
+
+                String selection = NoteColumns.CLOUD_NOTE_ID + " = ?";
+                String[] selectionArgs = new String[] { cloudNoteId };
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    null
+                );
+
+                WorkingNote note = null;
+                if (cursor != null) {
+                    if (cursor.moveToFirst()) {
+                        long noteId = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+                        note = WorkingNote.load(context, noteId);
+                    }
+                    cursor.close();
+                }
+
+                Log.d(TAG, "findByCloudNoteId: " + cloudNoteId + " found=" + (note != null));
+                callback.onSuccess(note);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to find note by cloudNoteId: " + cloudNoteId, e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 查询指定云端用户ID的笔记
+     *
+     * @param cloudUserId 云端用户ID
+     * @param callback 回调接口，返回笔记列表
+     */
+    public void getNotesByCloudUserId(String cloudUserId, Callback<List<WorkingNote>> callback) {
+        executor.execute(() -> {
+            try {
+                String selection = NoteColumns.CLOUD_USER_ID + " = ?";
+                String[] selectionArgs = new String[] { cloudUserId };
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    null
+                );
+
+                List<WorkingNote> notes = new ArrayList<>();
+                if (cursor != null) {
+                    while (cursor.moveToNext()) {
+                        long noteId = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+                        WorkingNote note = WorkingNote.load(context, noteId);
+                        notes.add(note);
+                    }
+                    cursor.close();
+                }
+
+                callback.onSuccess(notes);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to get notes by cloudUserId: " + cloudUserId, e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 更新笔记的云端用户ID（用于匿名用户迁移）
+     *
+     * @param oldUserId 旧的云端用户ID
+     * @param newUserId 新的云端用户ID
+     * @param callback 回调接口，返回更新的笔记数量
+     */
+    public void updateCloudUserId(String oldUserId, String newUserId, Callback<Integer> callback) {
+        executor.execute(() -> {
+            try {
+                ContentValues values = new ContentValues();
+                values.put(NoteColumns.CLOUD_USER_ID, newUserId);
+                values.put(NoteColumns.LOCAL_MODIFIED, 1);
+
+                String selection = NoteColumns.CLOUD_USER_ID + " = ?";
+                String[] selectionArgs = new String[] { oldUserId };
+
+                int rows = contentResolver.update(
+                    Notes.CONTENT_NOTE_URI,
+                    values,
+                    selection,
+                    selectionArgs
+                );
+
+                Log.d(TAG, "Updated " + rows + " notes from " + oldUserId + " to " + newUserId);
+                callback.onSuccess(rows);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to update cloudUserId", e);
+                callback.onError(e);
+            }
+        });
+    }
+
+    /**
+     * 批量标记笔记为已同步（带事务支持）
+     *
+     * @param noteIds 笔记ID列表
+     * @param callback 回调接口
+     */
+    public void batchMarkNotesSynced(List<Long> noteIds, Callback<Integer> callback) {
+        executor.execute(() -> {
+            int successCount = 0;
+            Exception lastError = null;
+
+            for (Long noteId : noteIds) {
+                try {
+                    ContentValues values = new ContentValues();
+                    values.put(NoteColumns.LOCAL_MODIFIED, 0);
+                values.put(NoteColumns.SYNC_STATUS, SyncConstants.SYNC_STATUS_SYNCED);
+                    values.put(NoteColumns.LAST_SYNC_TIME, System.currentTimeMillis());
+
+                    Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                    int rows = contentResolver.update(uri, values, null, null);
+
+                    if (rows > 0) {
+                        successCount++;
+                        Log.d(TAG, "Marked note " + noteId + " as synced");
+                    }
+                } catch (Exception e) {
+                    Log.e(TAG, "Failed to mark note as synced: " + noteId, e);
+                    lastError = e;
+                }
+            }
+
+            Log.d(TAG, "Batch sync completed: " + successCount + "/" + noteIds.size() + " notes marked as synced");
+
+            if (successCount == noteIds.size()) {
+                callback.onSuccess(successCount);
+            } else if (successCount > 0) {
+                callback.onSuccess(successCount);
+            } else {
+                callback.onError(lastError != null ? lastError : new Exception("All batch operations failed"));
+            }
+        });
+    }
+
+    /**
+     * 新用户接管设备上的所有笔记
+     * <p>
+     * 将设备上所有笔记（无论之前的cloud_user_id是谁）的cloud_user_id更新为新用户，
+     * 并标记为需要同步。这样新用户登录后可以把设备上的所有笔记上传到云端。
+     * </p>
+     *
+     * @param newUserId 新用户的云端ID
+     * @param callback 回调接口，返回接管的笔记数量
+     */
+    public void takeoverAllNotes(String newUserId, Callback<Integer> callback) {
+        executor.execute(() -> {
+            try {
+                // 1. 获取设备上所有笔记（排除系统文件夹）
+                String selection = NoteColumns.TYPE + " != ?";
+                String[] selectionArgs = new String[] { String.valueOf(Notes.TYPE_SYSTEM) };
+
+                Cursor cursor = contentResolver.query(
+                    Notes.CONTENT_NOTE_URI,
+                    null,
+                    selection,
+                    selectionArgs,
+                    null
+                );
+
+                int takeoverCount = 0;
+                if (cursor != null) {
+                    while (cursor.moveToNext()) {
+                        long noteId = cursor.getLong(cursor.getColumnIndexOrThrow(NoteColumns.ID));
+
+                        // 更新笔记的cloud_user_id为新用户，并标记为本地修改
+                        ContentValues values = new ContentValues();
+                        values.put(NoteColumns.CLOUD_USER_ID, newUserId);
+                        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+                        values.put(NoteColumns.SYNC_STATUS, 0);
+
+                        Uri uri = ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId);
+                        int rows = contentResolver.update(uri, values, null, null);
+
+                        if (rows > 0) {
+                            takeoverCount++;
+                        }
+                    }
+                    cursor.close();
+                }
+
+                Log.d(TAG, "Takeover completed: " + takeoverCount + " notes now belong to " + newUserId);
+                callback.onSuccess(takeoverCount);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to takeover notes for user: " + newUserId, e);
+                callback.onError(e);
+            }
+        });
+    }
 }

src/Notesmaster/app/src/main/java/net/micode/notes/model/CloudNote.java

@@ -0,0 +1,193 @@
+/*
+ * 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.model;
+
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * 云端笔记数据模型
+ * <p>
+ * 用于表示从云数据库下载的笔记数据
+ * </p>
+ */
+public class CloudNote {
+
+    private static final String TAG = "CloudNote";
+
+    private String mNoteId;
+    private String mCloudNoteId;
+    private String mTitle;
+    private String mContent;
+    private String mParentId;
+    private int mType;
+    private long mCreatedTime;
+    private long mModifiedTime;
+    private int mVersion;
+    private String mDeviceId;
+
+    /**
+     * 从JSON构造CloudNote
+     */
+    public CloudNote(JSONObject json) throws JSONException {
+        mCloudNoteId = json.optString("cloudNoteId", "");
+        mNoteId = json.optString("noteId", "");
+        mTitle = json.optString("title", "");
+        mContent = json.optString("content", "");
+        mParentId = json.optString("parentId", "0");
+        mType = json.optInt("type", 0);
+        mCreatedTime = json.optLong("createdTime", System.currentTimeMillis());
+        mModifiedTime = json.optLong("modifiedTime", System.currentTimeMillis());
+        mVersion = json.optInt("version", 1);
+        mDeviceId = json.optString("deviceId", "");
+    }
+
+    /**
+     * 从WorkingNote构造CloudNote（用于上传）
+     */
+    public CloudNote(WorkingNote note, String deviceId) {
+        mCloudNoteId = note.getCloudNoteId() != null ? note.getCloudNoteId() : "";
+        mNoteId = String.valueOf(note.getNoteId());
+        mTitle = note.getTitle();
+        mContent = note.getContent();
+        mParentId = String.valueOf(note.getFolderId());
+        mType = note.getType();
+        mCreatedTime = System.currentTimeMillis();
+        mModifiedTime = note.getModifiedDate();
+        mVersion = 1;
+        mDeviceId = deviceId;
+    }
+
+    /**
+     * 转换为WorkingNote
+     * 注意：这会创建一个新的本地笔记或更新现有笔记
+     * 修复：先检查本地是否存在该云端ID的笔记，决定是创建还是更新
+     */
+    public WorkingNote toWorkingNote(Context context, String userId) {
+        try {
+            long noteId = Long.parseLong(mNoteId);
+
+            // 先检查本地是否存在该云端ID的笔记
+            boolean existsInLocal = noteExistsInDatabase(context, noteId);
+
+            WorkingNote note;
+            if (existsInLocal) {
+                // 本地存在，加载并更新
+                note = WorkingNote.load(context, noteId);
+                Log.d(TAG, "Updating existing note from cloud: " + noteId);
+            } else {
+                // 本地不存在，创建新笔记（不指定ID，让数据库生成）
+                note = WorkingNote.createEmptyNote(context, 0);
+                Log.d(TAG, "Creating new note from cloud, cloud ID: " + noteId);
+            }
+
+            note.setType(mType);
+            note.setTitle(mTitle);
+            note.setContent(mContent);
+            note.setFolderId(Long.parseLong(mParentId));
+            note.setModifiedDate(mModifiedTime);
+            note.setCloudUserId(userId);
+
+            note.setCloudNoteId(mCloudNoteId);
+            note.setSyncStatus(net.micode.notes.sync.SyncConstants.SYNC_STATUS_SYNCED);
+            note.setLocalModified(0);
+            note.setLastSyncTime(System.currentTimeMillis());
+
+            return note;
+        } catch (Exception e) {
+            Log.e(TAG, "转换WorkingNote失败", e);
+            return null;
+        }
+    }
+
+    /**
+     * 检查指定ID的笔记是否在本地数据库存在
+     * @param context 应用上下文
+     * @param noteId 笔记ID（云端ID）
+     * @return 如果存在返回 true，否则返回 false
+     */
+    private boolean noteExistsInDatabase(Context context, long noteId) {
+        Cursor cursor = null;
+        try {
+            cursor = context.getContentResolver().query(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                    new String[]{Notes.NoteColumns.ID},
+                    null,
+                    null,
+                    null
+            );
+            boolean exists = cursor != null && cursor.getCount() > 0;
+            Log.d(TAG, "Note exists in local DB: " + noteId + " - " + exists);
+            return exists;
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to check note existence: " + noteId, e);
+            return false;
+        } finally {
+            if (cursor != null) {
+                cursor.close();
+            }
+        }
+    }
+
+    /**
+     * 转换为WorkingNote（向后兼容，使用默认userId）
+     * @deprecated 请使用 {@link #toWorkingNote(Context, String)}
+     */
+    @Deprecated
+    public WorkingNote toWorkingNote(Context context) {
+        return toWorkingNote(context, "");
+    }
+
+    /**
+     * 转换为JSON（用于上传）
+     */
+    public JSONObject toJson() throws JSONException {
+        JSONObject json = new JSONObject();
+        if (mCloudNoteId != null && !mCloudNoteId.isEmpty()) {
+            json.put("cloudNoteId", mCloudNoteId);
+        }
+        json.put("noteId", mNoteId);
+        json.put("title", mTitle);
+        json.put("content", mContent);
+        json.put("parentId", mParentId);
+        json.put("type", mType);
+        json.put("createdTime", mCreatedTime);
+        json.put("modifiedTime", mModifiedTime);
+        json.put("version", mVersion);
+        json.put("deviceId", mDeviceId);
+        return json;
+    }
+
+    // Getters
+    public String getCloudNoteId() { return mCloudNoteId; }
+    public String getNoteId() { return mNoteId; }
+    public String getTitle() { return mTitle; }
+    public String getContent() { return mContent; }
+    public String getParentId() { return mParentId; }
+    public int getType() { return mType; }
+    public long getCreatedTime() { return mCreatedTime; }
+    public long getModifiedTime() { return mModifiedTime; }
+    public int getVersion() { return mVersion; }
+    public String getDeviceId() { return mDeviceId; }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/model/Note.java

@@ -57,18 +57,34 @@ public class Note {
      * 在数据库中创建一条新笔记记录，并返回其 ID。
      * 初始化笔记的创建时间、修改时间、类型和父文件夹 ID。
      * </p>
-     * 
+     *
      * @param context 应用上下文
      * @param folderId 父文件夹 ID
      * @return 新创建的笔记 ID，失败时返回 0
      */
     public static synchronized long getNewNoteId(Context context, long folderId) {
+        return getNewNoteId(context, folderId, Notes.TYPE_NOTE);
+    }
+
+    /**
+     * 创建新笔记 ID（支持指定类型）
+     * <p>
+     * 在数据库中创建一条新笔记记录，并返回其 ID。
+     * 初始化笔记的创建时间、修改时间、类型和父文件夹 ID。
+     * </p>
+     *
+     * @param context 应用上下文
+     * @param folderId 父文件夹 ID
+     * @param type 笔记类型：0=普通笔记, 1=文件夹, 2=系统, 3=待办
+     * @return 新创建的笔记 ID，失败时返回 0
+     */
+    public static synchronized long getNewNoteId(Context context, long folderId, int type) {
         // 在数据库中创建新笔记
         ContentValues values = new ContentValues();
         long createdTime = System.currentTimeMillis();
         values.put(NoteColumns.CREATED_DATE, createdTime);
         values.put(NoteColumns.MODIFIED_DATE, createdTime);
-        values.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+        values.put(NoteColumns.TYPE, type);
         values.put(NoteColumns.LOCAL_MODIFIED, 1);
         values.put(NoteColumns.PARENT_ID, folderId);
         Uri uri = context.getContentResolver().insert(Notes.CONTENT_NOTE_URI, values);
@@ -421,5 +437,50 @@ public class Note {
             }
             return null;
         }
+
+        // ==================== 云同步相关方法 ====================
+
+        void setCloudUserId(String userId) {
+            mNoteDiffValues.put(NoteColumns.CLOUD_USER_ID, userId);
+        }
+
+        String getCloudUserId() {
+            return mNoteDiffValues.getAsString(NoteColumns.CLOUD_USER_ID);
+        }
+
+        void setCloudDeviceId(String deviceId) {
+            mNoteDiffValues.put(NoteColumns.CLOUD_DEVICE_ID, deviceId);
+        }
+
+        String getCloudDeviceId() {
+            return mNoteDiffValues.getAsString(NoteColumns.CLOUD_DEVICE_ID);
+        }
+
+        void setSyncStatus(int status) {
+            mNoteDiffValues.put(NoteColumns.SYNC_STATUS, status);
+        }
+
+        int getSyncStatus() {
+            Integer status = mNoteDiffValues.getAsInteger(NoteColumns.SYNC_STATUS);
+            return status != null ? status : 0;
+        }
+
+        void setLastSyncTime(long time) {
+            mNoteDiffValues.put(NoteColumns.LAST_SYNC_TIME, time);
+        }
+
+        long getLastSyncTime() {
+            Long time = mNoteDiffValues.getAsLong(NoteColumns.LAST_SYNC_TIME);
+            return time != null ? time : 0;
+        }
+
+        void setLocalModified(int modified) {
+            mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, modified);
+        }
+
+        int getLocalModified() {
+            Integer modified = mNoteDiffValues.getAsInteger(NoteColumns.LOCAL_MODIFIED);
+            return modified != null ? modified : 0;
+        }
     }
 }

src/Notesmaster/app/src/main/java/net/micode/notes/model/WorkingNote.java

@@ -73,9 +73,30 @@ public class WorkingNote {
     /** 父文件夹 ID */
     private long mFolderId;
 
+    /** 笔记类型: 0=普通笔记, 1=文件夹, 2=系统, 3=待办 */
+    private int mType;
+
     /** 应用上下文 */
     private Context mContext;
 
+    /** 同步状态 */
+    private int mSyncStatus;
+
+    /** 最后同步时间 */
+    private long mLastSyncTime;
+
+    /** 本地修改标记 */
+    private int mLocalModified;
+
+    /** 云端用户ID */
+    private String mCloudUserId;
+
+    /** 云端设备ID */
+    private String mCloudDeviceId;
+
+    /** 云端笔记ID */
+    private String mCloudNoteId;
+
     /** 日志标签 */
     private static final String TAG = "WorkingNote";
 
@@ -103,8 +124,10 @@ public class WorkingNote {
             NoteColumns.BG_COLOR_ID,
             NoteColumns.WIDGET_ID,
             NoteColumns.WIDGET_TYPE,
+            NoteColumns.LOCAL_MODIFIED,
             NoteColumns.MODIFIED_DATE,
-            NoteColumns.TITLE
+            NoteColumns.TITLE,
+            NoteColumns.TYPE
     };
 
     /** 数据 ID 列索引 */
@@ -135,7 +158,13 @@ public class WorkingNote {
     private static final int NOTE_WIDGET_TYPE_COLUMN = 4;
 
     /** 笔记修改日期列索引 */
-    private static final int NOTE_MODIFIED_DATE_COLUMN = 5;
+    private static final int NOTE_MODIFIED_DATE_COLUMN = 6;
+
+    /** 笔记类型列索引 */
+    private static final int NOTE_TYPE_COLUMN = 8;
+
+    /** 云端笔记ID列索引 */
+    private static final int NOTE_CLOUD_NOTE_ID_COLUMN = 9;
 
     /**
      * 新建笔记构造函数
@@ -159,6 +188,8 @@ public class WorkingNote {
         mIsDeleted = false;
         mMode = 0;
         mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+        mLocalModified = 1; // 新建笔记需要同步
+        mType = Notes.TYPE_NOTE; // 默认为普通笔记类型
     }
 
     /**
@@ -200,6 +231,7 @@ public class WorkingNote {
                 mWidgetType = cursor.getInt(NOTE_WIDGET_TYPE_COLUMN);
                 mAlertDate = cursor.getLong(NOTE_ALERTED_DATE_COLUMN);
                 mModifiedDate = cursor.getLong(NOTE_MODIFIED_DATE_COLUMN);
+                mType = cursor.getInt(NOTE_TYPE_COLUMN);
 
                 // Load title
                 int titleIndex = cursor.getColumnIndex(NoteColumns.TITLE);
@@ -208,6 +240,14 @@ public class WorkingNote {
                 } else {
                     mTitle = "";
                 }
+
+                // Load cloud note id
+                int cloudNoteIdIndex = cursor.getColumnIndex(NoteColumns.CLOUD_NOTE_ID);
+                if (cloudNoteIdIndex != -1) {
+                    mCloudNoteId = cursor.getString(cloudNoteIdIndex);
+                } else {
+                    mCloudNoteId = "";
+                }
             }
             cursor.close();
         } else {
@@ -258,7 +298,7 @@ public class WorkingNote {
      * <p>
      * 创建一个新的空笔记对象，并设置默认属性。
      * </p>
-     * 
+     *
      * @param context 应用上下文
      * @param folderId 父文件夹 ID
      * @param widgetId Widget ID
@@ -275,6 +315,21 @@ public class WorkingNote {
         return note;
     }
 
+    /**
+     * 创建空笔记（简化版）
+     * <p>
+     * 创建一个新的空笔记对象，用于云同步。
+     * </p>
+     *
+     * @param context 应用上下文
+     * @param noteId 笔记 ID
+     * @return 新创建的 WorkingNote 对象
+     */
+    public static WorkingNote createEmptyNote(Context context, long noteId) {
+        WorkingNote note = new WorkingNote(context, noteId, 0);
+        return note;
+    }
+
     /**
      * 加载已有笔记
      * <p>
@@ -378,6 +433,10 @@ public class WorkingNote {
     public void setTitle(String title) {
         mTitle = title;
         mNote.setNoteValue(NoteColumns.TITLE, mTitle);
+        // 对于文件夹类型，同时设置 snippet 字段以保持兼容性
+        if (mType == Notes.TYPE_FOLDER) {
+            mNote.setNoteValue(NoteColumns.SNIPPET, mTitle);
+        }
     }
 
     public String getTitle() {
@@ -622,13 +681,162 @@ public class WorkingNote {
 
     /**
      * 获取 Widget 类型
-     * 
+     *
      * @return Widget 类型
      */
     public int getWidgetType() {
         return mWidgetType;
     }
 
+    // ==================== 云同步相关方法 ====================
+
+    /**
+     * 设置云端用户ID
+     */
+    public void setCloudUserId(String userId) {
+        mCloudUserId = userId;
+    }
+
+    /**
+     * 获取云端用户ID
+     */
+    public String getCloudUserId() {
+        return mCloudUserId;
+    }
+
+    /**
+     * 设置云端设备ID
+     */
+    public void setCloudDeviceId(String deviceId) {
+        mCloudDeviceId = deviceId;
+    }
+
+    /**
+     * 获取云端设备ID
+     */
+    public String getCloudDeviceId() {
+        return mCloudDeviceId;
+    }
+
+    /**
+     * 设置同步状态
+     * @param status 0=未同步, 1=同步中, 2=已同步, 3=冲突
+     */
+    public void setSyncStatus(int status) {
+        mSyncStatus = status;
+    }
+
+    /**
+     * 获取同步状态
+     */
+    public int getSyncStatus() {
+        return mSyncStatus;
+    }
+
+    /**
+     * 设置最后同步时间
+     */
+    public void setLastSyncTime(long time) {
+        mLastSyncTime = time;
+    }
+
+    /**
+     * 获取最后同步时间
+     */
+    public long getLastSyncTime() {
+        return mLastSyncTime;
+    }
+
+    /**
+     * 设置本地修改标记
+     * @param modified 0=未修改, 1=已修改
+     */
+    public void setLocalModified(int modified) {
+        mLocalModified = modified;
+    }
+
+    /**
+     * 获取本地修改标记
+     */
+    public int getLocalModified() {
+        return mLocalModified;
+    }
+
+    /**
+     * 设置笔记内容
+     */
+    public void setContent(String content) {
+        mContent = content;
+        mNote.setTextData(DataColumns.CONTENT, mContent);
+    }
+
+    /**
+     * 设置文件夹ID
+     */
+    public void setFolderId(long folderId) {
+        mFolderId = folderId;
+        mNote.setNoteValue(NoteColumns.PARENT_ID, String.valueOf(mFolderId));
+    }
+
+    /**
+     * 设置修改日期
+     */
+    public void setModifiedDate(long date) {
+        mModifiedDate = date;
+        mNote.setNoteValue(NoteColumns.MODIFIED_DATE, String.valueOf(mModifiedDate));
+    }
+
+    /**
+     * 设置笔记类型
+     * @param type 0=普通笔记, 1=文件夹, 2=系统, 3=待办
+     */
+    public void setType(int type) {
+        mType = type;
+        mNote.setNoteValue(NoteColumns.TYPE, String.valueOf(mType));
+    }
+
+    /**
+     * 获取笔记类型
+     * @return 0=普通笔记, 1=文件夹, 2=系统, 3=待办
+     */
+    public int getType() {
+        return mType;
+    }
+
+    /**
+     * 获取云端笔记ID
+     * @return 云端笔记ID（UUID），未上传时为空字符串
+     */
+    public String getCloudNoteId() {
+        return mCloudNoteId;
+    }
+
+    /**
+     * 设置云端笔记ID
+     * @param cloudNoteId 云端笔记ID（UUID）
+     */
+    public void setCloudNoteId(String cloudNoteId) {
+        mCloudNoteId = cloudNoteId;
+        mNote.setNoteValue(NoteColumns.CLOUD_NOTE_ID, mCloudNoteId != null ? mCloudNoteId : "");
+    }
+
+    /**
+     * 从CloudNote更新当前笔记
+     * 用于云端下载后更新本地笔记
+     */
+    public void updateFrom(CloudNote cloudNote) {
+        setTitle(cloudNote.getTitle());
+        setContent(cloudNote.getContent());
+        setFolderId(Long.parseLong(cloudNote.getParentId()));
+        setModifiedDate(cloudNote.getModifiedTime());
+        setType(cloudNote.getType());
+        setCloudNoteId(cloudNote.getCloudNoteId());
+        setSyncStatus(net.micode.notes.sync.SyncConstants.SYNC_STATUS_SYNCED);
+        setLastSyncTime(System.currentTimeMillis());
+        setLocalModified(0);
+        saveNote();
+    }
+
     /**
      * 笔记设置变更监听器接口
      * <p>

src/Notesmaster/app/src/main/java/net/micode/notes/sync/Conflict.java

@@ -0,0 +1,112 @@
+/*
+ * 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.sync;
+
+import net.micode.notes.model.CloudNote;
+import net.micode.notes.model.WorkingNote;
+
+/**
+ * 冲突数据模型
+ * <p>
+ * 表示本地笔记和云端笔记的冲突
+ * </p>
+ */
+public class Conflict {
+
+    private WorkingNote mLocalNote;
+    private CloudNote mCloudNote;
+    private String mNoteId;
+    private long mConflictTime;
+    private ConflictType mType;
+
+    public enum ConflictType {
+        BOTH_MODIFIED,     // 双方都修改过
+        VERSION_MISMATCH   // 版本号不匹配
+    }
+
+    public Conflict(WorkingNote localNote, CloudNote cloudNote) {
+        this(localNote, cloudNote, ConflictType.BOTH_MODIFIED);
+    }
+
+    public Conflict(WorkingNote localNote, CloudNote cloudNote, ConflictType type) {
+        mLocalNote = localNote;
+        mCloudNote = cloudNote;
+        mNoteId = String.valueOf(localNote.getNoteId());
+        mConflictTime = System.currentTimeMillis();
+        mType = type;
+    }
+
+    public WorkingNote getLocalNote() {
+        return mLocalNote;
+    }
+
+    public CloudNote getCloudNote() {
+        return mCloudNote;
+    }
+
+    public String getNoteId() {
+        return mNoteId;
+    }
+
+    public long getConflictTime() {
+        return mConflictTime;
+    }
+
+    public ConflictType getType() {
+        return mType;
+    }
+
+    /**
+     * 获取冲突描述
+     */
+    public String getConflictDescription() {
+        return "本地修改时间: " + mLocalNote.getModifiedDate() +
+               "\n云端修改时间: " + mCloudNote.getModifiedTime();
+    }
+
+    /**
+     * 获取本地标题预览
+     */
+    public String getLocalTitle() {
+        return mLocalNote.getTitle();
+    }
+
+    /**
+     * 获取云端标题预览
+     */
+    public String getCloudTitle() {
+        return mCloudNote.getTitle();
+    }
+
+    /**
+     * 获取本地内容预览（前100字符）
+     */
+    public String getLocalContentPreview() {
+        String content = mLocalNote.getContent();
+        if (content == null) return "";
+        return content.length() > 100 ? content.substring(0, 100) + "..." : content;
+    }
+
+    /**
+     * 获取云端内容预览（前100字符）
+     */
+    public String getCloudContentPreview() {
+        String content = mCloudNote.getContent();
+        if (content == null) return "";
+        return content.length() > 100 ? content.substring(0, 100) + "..." : content;
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/sync/NotesPushMessageReceiver.java

@@ -0,0 +1,65 @@
+/*
+ * 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.sync;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.util.Log;
+
+/**
+ * 推送消息接收器
+ * <p>
+ * 接收云端推送的同步通知消息，触发本地同步操作。
+ * </p>
+ */
+public class NotesPushMessageReceiver extends BroadcastReceiver {
+
+    private static final String TAG = "NotesPushMessageReceiver";
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        if (intent == null || intent.getAction() == null) {
+            return;
+        }
+
+        String action = intent.getAction();
+        Log.d(TAG, "Received push message: " + action);
+
+        if ("com.alibaba.push2.action.NOTIFICATION_OPENED".equals(action)) {
+            handleNotificationOpened(context, intent);
+        } else if ("com.alibaba.push2.action.MESSAGE_RECEIVED".equals(action)) {
+            handleMessageReceived(context, intent);
+        }
+    }
+
+    private void handleNotificationOpened(Context context, Intent intent) {
+        Log.d(TAG, "Notification opened");
+        // TODO: Handle notification open action
+    }
+
+    private void handleMessageReceived(Context context, Intent intent) {
+        Log.d(TAG, "Message received");
+        // Check if this is a sync message
+        String messageAction = intent.getStringExtra("action");
+        if ("sync".equals(messageAction)) {
+            Log.d(TAG, "Sync action received, broadcasting sync intent");
+            Intent syncIntent = new Intent(SyncConstants.ACTION_SYNC);
+            context.sendBroadcast(syncIntent);
+        }
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/sync/SyncConstants.java

@@ -0,0 +1,55 @@
+/*
+ * 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.sync;
+
+/**
+ * 同步常量定义
+ * <p>
+ * 定义云同步功能中使用的所有常量，包括同步状态、错误码等。
+ * </p>
+ */
+public class SyncConstants {
+    
+    private SyncConstants() {
+        // Utility class, prevent instantiation
+    }
+    
+    /**
+     * 同步状态：未同步
+     */
+    public static final int SYNC_STATUS_NOT_SYNCED = 0;
+    
+    /**
+     * 同步状态：同步中
+     */
+    public static final int SYNC_STATUS_SYNCING = 1;
+    
+    /**
+     * 同步状态：已同步
+     */
+    public static final int SYNC_STATUS_SYNCED = 2;
+    
+    /**
+     * 同步状态：冲突
+     */
+    public static final int SYNC_STATUS_CONFLICT = 3;
+    
+    /**
+     * 同步广播Action
+     */
+    public static final String ACTION_SYNC = "com.micode.notes.ACTION_SYNC";
+}

src/Notesmaster/app/src/main/java/net/micode/notes/sync/SyncManager.java

@@ -0,0 +1,746 @@
+/*
+ * 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.sync;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.util.Log;
+
+import androidx.annotation.Nullable;
+
+import net.micode.notes.api.CloudCallback;
+import net.micode.notes.api.CloudDatabaseHelper;
+import net.micode.notes.auth.UserAuthManager;
+import net.micode.notes.data.NotesRepository;
+import net.micode.notes.model.CloudNote;
+import net.micode.notes.model.WorkingNote;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * 同步管理器
+ * <p>
+ * 负责管理笔记的云同步操作，包括上传本地修改、下载云端更新、处理冲突等。
+ * 使用单例模式确保全局只有一个同步管理器实例。
+ * </p>
+ * <p>
+ * 修复记录：
+ * 1. 修复同步时间更新逻辑 - 确保所有笔记处理完成后再更新时间戳
+ * 2. 优化线程同步机制 - 使用 CountDownLatch 替代 synchronized/wait/notify
+ * 3. 添加全量同步支持 - 支持强制下载所有云端笔记
+ * 4. 添加同步进度回调 - 支持实时显示同步进度
+ * </p>
+ */
+public class SyncManager {
+
+    private static final String TAG = "SyncManager";
+    private static final String PREFS_SYNC = "sync_settings";
+    private static final String KEY_LAST_SYNC = "last_sync_time";
+    private static final String KEY_IS_FIRST_SYNC = "is_first_sync";
+    private static final long SYNC_TIMEOUT_SECONDS = 60;
+
+    private final ExecutorService mExecutor;
+    private Context mContext;
+    private SharedPreferences mPrefs;
+    private List<Conflict> mConflicts;
+    private ConflictListener mConflictListener;
+
+    /**
+     * 静态内部类实现单例模式（Initialization-on-demand holder idiom）
+     */
+    private static class Holder {
+        private static final SyncManager INSTANCE = new SyncManager();
+    }
+
+    private SyncManager() {
+        mExecutor = Executors.newSingleThreadExecutor();
+        mConflicts = new ArrayList<>();
+    }
+
+    /**
+     * 同步回调接口
+     */
+    public interface SyncCallback {
+        void onSuccess();
+        void onError(String error);
+    }
+
+    /**
+     * 同步进度回调接口
+     */
+    public interface SyncProgressCallback {
+        void onProgress(int current, int total, String message);
+    }
+
+    /**
+     * 冲突监听器接口
+     */
+    public interface ConflictListener {
+        void onConflictDetected(Conflict conflict);
+    }
+
+    /**
+     * 获取SyncManager单例实例
+     *
+     * @return SyncManager实例
+     */
+    public static SyncManager getInstance() {
+        return Holder.INSTANCE;
+    }
+
+    /**
+     * 初始化SyncManager
+     *
+     * @param context 应用上下文
+     */
+    public void initialize(Context context) {
+        mContext = context.getApplicationContext();
+        mPrefs = mContext.getSharedPreferences(PREFS_SYNC, Context.MODE_PRIVATE);
+        Log.d(TAG, "SyncManager initialized");
+    }
+
+    /**
+     * 设置冲突监听器
+     *
+     * @param listener 冲突监听器
+     */
+    public void setConflictListener(ConflictListener listener) {
+        mConflictListener = listener;
+    }
+
+    /**
+     * 移除冲突
+     *
+     * @param conflict 要移除的冲突
+     */
+    public void removeConflict(Conflict conflict) {
+        mConflicts.remove(conflict);
+    }
+
+    /**
+     * 执行笔记同步（增量同步）
+     *
+     * @param callback 同步回调
+     */
+    public void syncNotes(SyncCallback callback) {
+        syncNotesInternal(false, callback, null);
+    }
+
+    /**
+     * 执行全量同步（强制下载所有云端笔记）
+     *
+     * @param callback 同步回调
+     */
+    public void syncAllNotes(SyncCallback callback) {
+        syncNotesInternal(true, callback, null);
+    }
+
+    /**
+     * 上传所有本地笔记到云端
+     * <p>
+     * 用于新用户登录后，将设备上所有笔记上传到云端。
+     * 不管笔记的 LOCAL_MODIFIED 状态如何，都会上传。
+     * </p>
+     *
+     * @param callback 同步回调
+     */
+    public void uploadAllNotes(SyncCallback callback) {
+        Log.d(TAG, "========== Starting upload all notes ==========");
+
+        mExecutor.execute(() -> {
+            try {
+                performUploadAll();
+                Log.d(TAG, "Upload all notes completed successfully");
+                if (callback != null) {
+                    callback.onSuccess();
+                }
+            } catch (Exception e) {
+                Log.e(TAG, "Upload all notes failed", e);
+                if (callback != null) {
+                    callback.onError(e.getMessage());
+                }
+            }
+        });
+    }
+
+    /**
+     * 执行笔记同步（带进度回调）
+     *
+     * @param forceFullSync 是否强制全量同步
+     * @param callback 同步回调
+     * @param progressCallback 进度回调
+     */
+    public void syncNotesWithProgress(boolean forceFullSync, SyncCallback callback, 
+            SyncProgressCallback progressCallback) {
+        syncNotesInternal(forceFullSync, callback, progressCallback);
+    }
+
+    /**
+     * 内部同步方法
+     */
+    private void syncNotesInternal(boolean forceFullSync, SyncCallback callback, 
+            SyncProgressCallback progressCallback) {
+        Log.d(TAG, "========== Starting sync operation ==========");
+        Log.d(TAG, "Force full sync: " + forceFullSync);
+
+        mExecutor.execute(() -> {
+            try {
+                performSync(forceFullSync, progressCallback);
+                Log.d(TAG, "Sync completed successfully");
+                if (callback != null) {
+                    callback.onSuccess();
+                }
+            } catch (Exception e) {
+                Log.e(TAG, "Sync failed", e);
+                if (callback != null) {
+                    callback.onError(e.getMessage());
+                }
+            }
+        });
+    }
+
+    /**
+     * 执行实际的同步操作
+     */
+    private void performSync(boolean forceFullSync, SyncProgressCallback progressCallback) throws Exception {
+        UserAuthManager authManager = UserAuthManager.getInstance(mContext);
+        if (!authManager.isLoggedIn()) {
+            throw new RuntimeException("用户未登录");
+        }
+
+        // 检查并刷新Token
+        ensureValidToken(authManager);
+
+        NotesRepository repo = new NotesRepository(mContext);
+        String authToken = authManager.getAuthToken();
+        Log.d(TAG, "Auth token: " + (authToken != null ? authToken.substring(0, Math.min(20, authToken.length())) + "..." : "null"));
+        
+        CloudDatabaseHelper cloudHelper = new CloudDatabaseHelper(
+            authManager.getUserId(),
+            authManager.getDeviceId(),
+            authToken
+        );
+
+        // 1. 上传本地修改的笔记（只上传当前用户的笔记）
+        if (progressCallback != null) {
+            progressCallback.onProgress(0, 100, "正在上传本地修改...");
+        }
+        uploadNotesSync(repo, cloudHelper, progressCallback, authManager.getUserId());
+
+        // 2. 下载云端更新的笔记
+        if (progressCallback != null) {
+            progressCallback.onProgress(50, 100, "正在下载云端更新...");
+        }
+        boolean downloadSuccess = downloadNotesSync(repo, cloudHelper, forceFullSync, progressCallback, authManager.getUserId());
+
+        // 3. 只有在下载成功后才更新同步时间
+        if (downloadSuccess) {
+            updateSyncFlags();
+            // 标记已完成首次同步
+            markFirstSyncCompleted();
+        } else {
+            throw new RuntimeException("下载云端笔记失败，同步时间未更新");
+        }
+    }
+
+    /**
+     * 确保Token有效
+     */
+    private void ensureValidToken(UserAuthManager authManager) throws Exception {
+        if (authManager.isTokenExpired()) {
+            Log.w(TAG, "Token已过期，尝试刷新...");
+            final CountDownLatch latch = new CountDownLatch(1);
+            final AtomicBoolean refreshSuccess = new AtomicBoolean(false);
+            final AtomicReference<String> errorMsg = new AtomicReference<>();
+
+            authManager.refreshToken(new UserAuthManager.TokenRefreshCallback() {
+                @Override
+                public void onSuccess(String newToken) {
+                    Log.d(TAG, "Token刷新成功");
+                    refreshSuccess.set(true);
+                    latch.countDown();
+                }
+
+                @Override
+                public void onError(String error) {
+                    Log.e(TAG, "Token刷新失败: " + error);
+                    errorMsg.set(error);
+                    latch.countDown();
+                }
+            });
+
+            boolean completed = latch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+            if (!completed || !refreshSuccess.get()) {
+                throw new RuntimeException("Token刷新失败: " + errorMsg.get());
+            }
+        }
+    }
+
+    /**
+     * 同步方式上传笔记
+     */
+    private void uploadNotesSync(NotesRepository repo, CloudDatabaseHelper cloudHelper,
+            SyncProgressCallback progressCallback, String userId) throws Exception {
+        Log.d(TAG, "Uploading local modified notes for user: " + userId);
+
+        final List<WorkingNote> notesToUpload = new ArrayList<>();
+        final CountDownLatch queryLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> errorRef = new AtomicReference<>();
+
+        // 使用带用户过滤的方法，只查询当前用户的笔记
+        repo.getLocalModifiedNotes(userId, new NotesRepository.Callback<List<WorkingNote>>() {
+            @Override
+            public void onSuccess(List<WorkingNote> notes) {
+                notesToUpload.addAll(notes);
+                queryLatch.countDown();
+            }
+
+            @Override
+            public void onError(Exception e) {
+                errorRef.set(e);
+                queryLatch.countDown();
+            }
+        });
+
+        boolean completed = queryLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        if (!completed) {
+            throw new RuntimeException("查询本地修改笔记超时");
+        }
+        if (errorRef.get() != null) {
+            throw errorRef.get();
+        }
+
+        Log.d(TAG, "Found " + notesToUpload.size() + " notes to upload");
+
+        int total = notesToUpload.size();
+        for (int i = 0; i < total; i++) {
+            WorkingNote note = notesToUpload.get(i);
+            
+            if (progressCallback != null) {
+                int progress = (i * 50) / total; // 上传占50%进度
+                progressCallback.onProgress(progress, 100, "正在上传笔记 " + (i + 1) + "/" + total);
+            }
+
+            uploadSingleNote(repo, cloudHelper, note);
+        }
+    }
+
+    /**
+     * 上传单条笔记
+     */
+    private void uploadSingleNote(NotesRepository repo, CloudDatabaseHelper cloudHelper, 
+            WorkingNote note) throws Exception {
+        final CountDownLatch uploadLatch = new CountDownLatch(1);
+        final AtomicReference<String> cloudIdRef = new AtomicReference<>();
+        final AtomicReference<Exception> errorRef = new AtomicReference<>();
+
+        cloudHelper.uploadNote(note, new CloudCallback<String>() {
+            @Override
+            public void onSuccess(String result) {
+                cloudIdRef.set(result);
+                uploadLatch.countDown();
+            }
+
+            @Override
+            public void onError(String err) {
+                errorRef.set(new Exception(err));
+                uploadLatch.countDown();
+            }
+        });
+
+        boolean completed = uploadLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        if (!completed) {
+            throw new RuntimeException("上传笔记超时: " + note.getNoteId());
+        }
+        if (errorRef.get() != null) {
+            Log.e(TAG, "Failed to upload note: " + note.getNoteId(), errorRef.get());
+            return; // 继续处理其他笔记
+        }
+
+        Log.d(TAG, "Uploaded note: " + note.getNoteId() + " with cloudId: " + cloudIdRef.get());
+
+        String cloudNoteId = cloudIdRef.get();
+        if (cloudNoteId != null && !cloudNoteId.isEmpty()) {
+            note.setCloudNoteId(cloudNoteId);
+            if (!note.saveNote()) {
+                Log.w(TAG, "Failed to save cloudNoteId for note: " + note.getNoteId());
+            }
+        }
+
+        markNoteAsSynced(repo, note.getNoteId());
+    }
+
+    /**
+     * 标记笔记为已同步
+     */
+    private void markNoteAsSynced(NotesRepository repo, long noteId) throws Exception {
+        final CountDownLatch markLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> errorRef = new AtomicReference<>();
+
+        repo.markNoteSynced(noteId, new NotesRepository.Callback<Void>() {
+            @Override
+            public void onSuccess(Void result) {
+                markLatch.countDown();
+            }
+
+            @Override
+            public void onError(Exception e) {
+                errorRef.set(e);
+                markLatch.countDown();
+            }
+        });
+
+        boolean completed = markLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        if (!completed) {
+            throw new RuntimeException("标记笔记同步状态超时: " + noteId);
+        }
+        if (errorRef.get() != null) {
+            throw errorRef.get();
+        }
+
+        Log.d(TAG, "Marked note " + noteId + " as synced");
+    }
+
+    /**
+     * 上传所有本地笔记到云端（不管modified状态）
+     */
+    private void performUploadAll() throws Exception {
+        UserAuthManager authManager = UserAuthManager.getInstance(mContext);
+        if (!authManager.isLoggedIn()) {
+            throw new RuntimeException("用户未登录");
+        }
+
+        String userId = authManager.getUserId();
+        String authToken = authManager.getAuthToken();
+        Log.d(TAG, "Uploading all notes for user: " + userId);
+
+        NotesRepository repo = new NotesRepository(mContext);
+        CloudDatabaseHelper cloudHelper = new CloudDatabaseHelper(
+            userId,
+            authManager.getDeviceId(),
+            authToken
+        );
+
+        // 获取当前用户的所有笔记（不管modified状态）
+        final List<WorkingNote> allNotes = new ArrayList<>();
+        final CountDownLatch queryLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> errorRef = new AtomicReference<>();
+
+        repo.getNotesByCloudUserId(userId, new NotesRepository.Callback<List<WorkingNote>>() {
+            @Override
+            public void onSuccess(List<WorkingNote> notes) {
+                allNotes.addAll(notes);
+                queryLatch.countDown();
+            }
+
+            @Override
+            public void onError(Exception e) {
+                errorRef.set(e);
+                queryLatch.countDown();
+            }
+        });
+
+        boolean completed = queryLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        if (!completed) {
+            throw new RuntimeException("查询笔记超时");
+        }
+        if (errorRef.get() != null) {
+            throw errorRef.get();
+        }
+
+        Log.d(TAG, "Found " + allNotes.size() + " notes to upload");
+
+        // 上传所有笔记
+        int total = allNotes.size();
+        int successCount = 0;
+        for (int i = 0; i < total; i++) {
+            WorkingNote note = allNotes.get(i);
+            try {
+                uploadSingleNote(repo, cloudHelper, note);
+                successCount++;
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to upload note: " + note.getNoteId(), e);
+                // 继续上传其他笔记
+            }
+        }
+
+        Log.d(TAG, "Upload completed: " + successCount + "/" + total + " notes uploaded");
+
+        // 更新同步时间
+        updateSyncFlags();
+        markFirstSyncCompleted();
+    }
+
+    /**
+     * 同步方式下载笔记
+     * 
+     * @return 是否下载成功
+     */
+    private boolean downloadNotesSync(NotesRepository repo, CloudDatabaseHelper cloudHelper,
+            boolean forceFullSync, SyncProgressCallback progressCallback, String userId) throws Exception {
+        Log.d(TAG, "Downloading cloud updates");
+
+        long lastSyncTime = forceFullSync ? 0 : mPrefs.getLong(KEY_LAST_SYNC, 0);
+        Log.d(TAG, "Last sync time: " + lastSyncTime + (forceFullSync ? " (强制全量同步)" : ""));
+        
+        // 首次同步时传递 0，获取所有笔记
+        // 后续同步只获取修改过的笔记
+        long downloadSince = (lastSyncTime == 0) ? 0 : lastSyncTime;
+        
+        final AtomicReference<JSONArray> notesArrayRef = new AtomicReference<>();
+        final CountDownLatch downloadLatch = new CountDownLatch(1);
+        final AtomicReference<Exception> errorRef = new AtomicReference<>();
+        final AtomicLong maxModifiedTime = new AtomicLong(0);
+
+        cloudHelper.downloadNotes(downloadSince, new CloudCallback<JSONArray>() {
+            @Override
+            public void onSuccess(JSONArray result) {
+                notesArrayRef.set(result);
+                
+                // 计算云端最新修改时间
+                long latestCloudTime = 0;
+                try {
+                    for (int i = 0; i < result.length(); i++) {
+                        JSONObject noteJson = result.getJSONObject(i);
+                        long modifiedTime = noteJson.optLong("modifiedTime", 0);
+                        if (modifiedTime > latestCloudTime) {
+                            latestCloudTime = modifiedTime;
+                        }
+                    }
+                    maxModifiedTime.set(latestCloudTime);
+                } catch (Exception e) {
+                    Log.e(TAG, "Failed to calculate latest cloud time", e);
+                }
+                
+                downloadLatch.countDown();
+            }
+
+            @Override
+            public void onError(String err) {
+                errorRef.set(new Exception(err));
+                downloadLatch.countDown();
+            }
+        });
+
+        boolean completed = downloadLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        if (!completed) {
+            throw new RuntimeException("下载云端笔记超时");
+        }
+        if (errorRef.get() != null) {
+            throw errorRef.get();
+        }
+
+        JSONArray notesArray = notesArrayRef.get();
+        if (notesArray == null) {
+            Log.w(TAG, "Downloaded notes array is null");
+            return true; // 视为成功，只是没有数据
+        }
+
+        Log.d(TAG, "Downloaded " + notesArray.length() + " notes from cloud");
+
+        // 处理下载的笔记
+        int total = notesArray.length();
+        int successCount = 0;
+        
+        for (int i = 0; i < total; i++) {
+            if (progressCallback != null) {
+                int progress = 50 + (i * 50) / total; // 下载占50-100%进度
+                progressCallback.onProgress(progress, 100, "正在处理笔记 " + (i + 1) + "/" + total);
+            }
+
+            CloudNote cloudNote = new CloudNote(notesArray.getJSONObject(i));
+            boolean processed = processDownloadedNote(repo, cloudNote, userId);
+            if (processed) {
+                successCount++;
+            }
+        }
+
+        Log.d(TAG, "Successfully processed " + successCount + "/" + total + " notes");
+
+        // 只有在所有笔记都处理成功后才更新同步时间
+        if (successCount == total) {
+            // 使用云端最新修改时间更新 lastSyncTime
+            if (maxModifiedTime.get() > 0) {
+                updateLastSyncTime(maxModifiedTime.get());
+                Log.d(TAG, "Updated last sync time to: " + maxModifiedTime.get());
+            }
+            return true;
+        } else {
+            Log.w(TAG, "Some notes failed to process, not updating sync time");
+            return false;
+        }
+    }
+
+    /**
+     * 处理下载的单条笔记
+     *
+     * @return 是否处理成功
+     */
+    private boolean processDownloadedNote(NotesRepository repo, CloudNote cloudNote, String userId) {
+        final CountDownLatch findLatch = new CountDownLatch(1);
+        final AtomicReference<WorkingNote> localNoteRef = new AtomicReference<>();
+
+        String cloudNoteId = cloudNote.getCloudNoteId();
+        if (cloudNoteId != null && !cloudNoteId.isEmpty()) {
+            repo.findByCloudNoteId(cloudNoteId, new NotesRepository.Callback<WorkingNote>() {
+                @Override
+                public void onSuccess(WorkingNote result) {
+                    localNoteRef.set(result);
+                    findLatch.countDown();
+                }
+
+                @Override
+                public void onError(Exception e) {
+                    Log.e(TAG, "Failed to find note by cloudNoteId: " + cloudNoteId, e);
+                    findLatch.countDown();
+                }
+            });
+        } else {
+            repo.findNoteByNoteId(cloudNote.getNoteId(), new NotesRepository.Callback<WorkingNote>() {
+                @Override
+                public void onSuccess(WorkingNote result) {
+                    localNoteRef.set(result);
+                    findLatch.countDown();
+                }
+
+                @Override
+                public void onError(Exception e) {
+                    Log.e(TAG, "Failed to find note by noteId: " + cloudNote.getNoteId(), e);
+                    findLatch.countDown();
+                }
+            });
+        }
+
+        try {
+            boolean completed = findLatch.await(SYNC_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+            if (!completed) {
+                Log.e(TAG, "查询本地笔记超时: " + cloudNote.getCloudNoteId());
+                return false;
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            return false;
+        }
+
+        WorkingNote localNote = localNoteRef.get();
+
+        if (localNote == null) {
+            // 本地不存在，插入新笔记
+            Log.d(TAG, "Inserting new note from cloud: cloudNoteId=" + cloudNote.getCloudNoteId());
+            WorkingNote newNote = cloudNote.toWorkingNote(mContext, userId);
+            if (newNote != null) {
+                newNote.saveNote();
+                return true;
+            }
+            return false;
+        } else {
+            // 本地已存在，检查版本
+            if (cloudNote.getModifiedTime() > localNote.getModifiedDate()) {
+                if (localNote.getLocalModified() == 0) {
+                    // 本地未修改，直接覆盖
+                    Log.d(TAG, "Updating local note from cloud: cloudNoteId=" + cloudNote.getCloudNoteId());
+                    localNote.updateFrom(cloudNote);
+                    localNote.saveNote();
+                    return true;
+                } else {
+                    // 双方都修改过，记录冲突
+                    Log.d(TAG, "Conflict detected for note: cloudNoteId=" + cloudNote.getCloudNoteId());
+                    mConflicts.add(new Conflict(localNote, cloudNote));
+                    return true;
+                }
+            }
+            return true;
+        }
+    }
+
+    /**
+     * 更新同步标志
+     */
+    private void updateSyncFlags() {
+        long currentTime = System.currentTimeMillis();
+        mPrefs.edit().putLong(KEY_LAST_SYNC, currentTime).apply();
+        Log.d(TAG, "Sync time updated: " + currentTime);
+    }
+
+    /**
+     * 更新最后同步时间
+     */
+    private void updateLastSyncTime(long syncTime) {
+        mPrefs.edit().putLong(KEY_LAST_SYNC, syncTime).apply();
+        Log.d(TAG, "Saved last sync time: " + syncTime);
+    }
+
+    /**
+     * 标记已完成首次同步
+     */
+    private void markFirstSyncCompleted() {
+        mPrefs.edit().putBoolean(KEY_IS_FIRST_SYNC, false).apply();
+        Log.d(TAG, "First sync marked as completed");
+    }
+
+    /**
+     * 检查是否是首次同步
+     */
+    public boolean isFirstSync() {
+        return mPrefs.getBoolean(KEY_IS_FIRST_SYNC, true);
+    }
+
+    /**
+     * 重置同步状态（用于重新安装后强制全量同步）
+     */
+    public void resetSyncState() {
+        mPrefs.edit()
+            .remove(KEY_LAST_SYNC)
+            .putBoolean(KEY_IS_FIRST_SYNC, true)
+            .apply();
+        Log.d(TAG, "Sync state reset");
+    }
+
+    /**
+     * 获取最后同步时间
+     */
+    public long getLastSyncTime() {
+        return mPrefs.getLong(KEY_LAST_SYNC, 0);
+    }
+
+    /**
+     * 获取待解决冲突列表
+     */
+    public List<Conflict> getPendingConflicts() {
+        return new ArrayList<>(mConflicts);
+    }
+
+    /**
+     * 清除所有冲突
+     */
+    public void clearAllConflicts() {
+        mConflicts.clear();
+        Log.d(TAG, "All conflicts cleared");
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/sync/SyncWorker.java

@@ -0,0 +1,118 @@
+/*
+ * 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.sync;
+
+import android.content.Context;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.work.Constraints;
+import androidx.work.NetworkType;
+import androidx.work.PeriodicWorkRequest;
+import androidx.work.WorkManager;
+import androidx.work.Worker;
+import androidx.work.WorkerParameters;
+import androidx.work.ExistingPeriodicWorkPolicy;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * 同步Worker
+ * <p>
+ * 使用WorkManager执行后台同步任务，定期同步笔记到云端。
+ * </p>
+ */
+public class SyncWorker extends Worker {
+
+    private static final String TAG = "SyncWorker";
+    private static final String WORK_NAME = "cloudSync";
+
+    public SyncWorker(@NonNull Context context, @NonNull WorkerParameters params) {
+        super(context, params);
+    }
+
+    @NonNull
+    @Override
+    public Result doWork() {
+        Log.d(TAG, "Starting background sync work");
+
+        final CountDownLatch latch = new CountDownLatch(1);
+        final boolean[] success = {false};
+
+        SyncManager.getInstance().syncNotes(new SyncManager.SyncCallback() {
+            @Override
+            public void onSuccess() {
+                Log.d(TAG, "Background sync completed successfully");
+                success[0] = true;
+                latch.countDown();
+            }
+
+            @Override
+            public void onError(String error) {
+                Log.e(TAG, "Background sync failed: " + error);
+                success[0] = false;
+                latch.countDown();
+            }
+        });
+
+        try {
+            latch.await(60, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+            Log.e(TAG, "Sync work interrupted", e);
+            return Result.retry();
+        }
+
+        return success[0] ? Result.success() : Result.retry();
+    }
+
+    /**
+     * 初始化定期同步任务
+     *
+     * @param context 应用上下文
+     */
+    public static void initialize(Context context) {
+        Log.d(TAG, "Initializing periodic sync work");
+
+        Constraints constraints = new Constraints.Builder()
+                .setRequiredNetworkType(NetworkType.CONNECTED)
+                .setRequiresBatteryNotLow(true)
+                .build();
+
+        PeriodicWorkRequest syncWork = new PeriodicWorkRequest.Builder(
+                SyncWorker.class, 30, TimeUnit.MINUTES)
+                .setConstraints(constraints)
+                .build();
+
+        WorkManager.getInstance(context).enqueueUniquePeriodicWork(
+                WORK_NAME,
+                ExistingPeriodicWorkPolicy.REPLACE,
+                syncWork);
+
+        Log.d(TAG, "Periodic sync work scheduled (30 minutes interval)");
+    }
+
+    /**
+     * 取消定期同步任务
+     *
+     * @param context 应用上下文
+     */
+    public static void cancel(Context context) {
+        Log.d(TAG, "Canceling periodic sync work");
+        WorkManager.getInstance(context).cancelUniqueWork(WORK_NAME);
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/ui/ConflictResolutionDialog.java

@@ -0,0 +1,217 @@
+/*
+ * 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.ui;
+
+import android.app.Dialog;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.DialogFragment;
+
+import com.google.android.material.button.MaterialButton;
+import com.google.android.material.dialog.MaterialAlertDialogBuilder;
+
+import net.micode.notes.R;
+import net.micode.notes.model.WorkingNote;
+
+/**
+ * 冲突解决对话框
+ * <p>
+ * 当本地笔记和云端笔记发生冲突时显示，让用户选择保留哪个版本。
+ * </p>
+ */
+public class ConflictResolutionDialog extends DialogFragment {
+
+    private static final String TAG = "ConflictResolutionDialog";
+    private static final String ARG_LOCAL_TITLE = "local_title";
+    private static final String ARG_LOCAL_CONTENT = "local_content";
+    private static final String ARG_CLOUD_TITLE = "cloud_title";
+    private static final String ARG_CLOUD_CONTENT = "cloud_content";
+
+    private ConflictResolutionListener mListener;
+
+    /**
+     * 冲突解决监听器接口
+     */
+    public interface ConflictResolutionListener {
+        void onChooseLocal();
+        void onChooseCloud();
+        void onMerge(String mergedTitle, String mergedContent);
+    }
+
+    /**
+     * 创建冲突解决对话框实例
+     *
+     * @param localNote 本地笔记
+     * @param cloudNote 云端笔记
+     * @return ConflictResolutionDialog实例
+     */
+    public static ConflictResolutionDialog newInstance(WorkingNote localNote, WorkingNote cloudNote) {
+        ConflictResolutionDialog dialog = new ConflictResolutionDialog();
+        Bundle args = new Bundle();
+        args.putString(ARG_LOCAL_TITLE, localNote.getTitle());
+        args.putString(ARG_LOCAL_CONTENT, localNote.getContent());
+        args.putString(ARG_CLOUD_TITLE, cloudNote.getTitle());
+        args.putString(ARG_CLOUD_CONTENT, cloudNote.getContent());
+        dialog.setArguments(args);
+        return dialog;
+    }
+
+    /**
+     * 设置冲突解决监听器
+     *
+     * @param listener 监听器
+     */
+    public void setConflictResolutionListener(ConflictResolutionListener listener) {
+        mListener = listener;
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+        MaterialAlertDialogBuilder builder = new MaterialAlertDialogBuilder(requireContext());
+
+        LayoutInflater inflater = requireActivity().getLayoutInflater();
+        View view = inflater.inflate(R.layout.dialog_conflict_resolution, null);
+
+        // Get arguments
+        Bundle args = getArguments();
+        if (args != null) {
+            String localTitle = args.getString(ARG_LOCAL_TITLE, "");
+            String localContent = args.getString(ARG_LOCAL_CONTENT, "");
+            String cloudTitle = args.getString(ARG_CLOUD_TITLE, "");
+            String cloudContent = args.getString(ARG_CLOUD_CONTENT, "");
+
+            // Set content previews (first 100 chars)
+            TextView tvLocalContent = view.findViewById(R.id.tv_local_content);
+            tvLocalContent.setText(truncateContent(localTitle, localContent));
+
+            TextView tvCloudContent = view.findViewById(R.id.tv_cloud_content);
+            tvCloudContent.setText(truncateContent(cloudTitle, cloudContent));
+        }
+
+        // Setup buttons
+        MaterialButton btnUseLocal = view.findViewById(R.id.btn_use_local);
+        MaterialButton btnUseCloud = view.findViewById(R.id.btn_use_cloud);
+        MaterialButton btnMerge = view.findViewById(R.id.btn_merge);
+
+        btnUseLocal.setOnClickListener(v -> {
+            Log.d(TAG, "User chose local version");
+            if (mListener != null) {
+                mListener.onChooseLocal();
+            }
+            dismiss();
+        });
+
+        btnUseCloud.setOnClickListener(v -> {
+            Log.d(TAG, "User chose cloud version");
+            if (mListener != null) {
+                mListener.onChooseCloud();
+            }
+            dismiss();
+        });
+
+        btnMerge.setOnClickListener(v -> {
+            Log.d(TAG, "User chose merge");
+            showMergeDialog(args);
+        });
+
+        builder.setView(view);
+        return builder.create();
+    }
+
+    private String truncateContent(String title, String content) {
+        String fullText = title + "\n" + content;
+        if (fullText.length() > 100) {
+            return fullText.substring(0, 100) + "...";
+        }
+        return fullText;
+    }
+
+    /**
+     * 显示合并编辑对话框
+     */
+    private void showMergeDialog(Bundle args) {
+        if (args == null) return;
+
+        String localTitle = args.getString(ARG_LOCAL_TITLE, "");
+        String localContent = args.getString(ARG_LOCAL_CONTENT, "");
+        String cloudTitle = args.getString(ARG_CLOUD_TITLE, "");
+        String cloudContent = args.getString(ARG_CLOUD_CONTENT, "");
+
+        // 智能合并：合并标题和内容
+        String mergedTitle = mergeText(localTitle, cloudTitle);
+        String mergedContent = mergeText(localContent, cloudContent);
+
+        // 创建编辑对话框
+        androidx.appcompat.app.AlertDialog.Builder builder = new androidx.appcompat.app.AlertDialog.Builder(requireContext());
+        builder.setTitle("合并笔记");
+
+        // 创建输入布局
+        android.widget.LinearLayout layout = new android.widget.LinearLayout(requireContext());
+        layout.setOrientation(android.widget.LinearLayout.VERTICAL);
+        layout.setPadding(50, 30, 50, 30);
+
+        // 标题输入
+        final android.widget.EditText etTitle = new android.widget.EditText(requireContext());
+        etTitle.setHint("标题");
+        etTitle.setText(mergedTitle);
+        layout.addView(etTitle);
+
+        // 内容输入
+        final android.widget.EditText etContent = new android.widget.EditText(requireContext());
+        etContent.setHint("内容");
+        etContent.setText(mergedContent);
+        etContent.setMinLines(5);
+        layout.addView(etContent);
+
+        builder.setView(layout);
+
+        builder.setPositiveButton("保存", (dialog, which) -> {
+            String finalTitle = etTitle.getText().toString().trim();
+            String finalContent = etContent.getText().toString().trim();
+
+            if (mListener != null) {
+                mListener.onMerge(finalTitle, finalContent);
+            }
+            dismiss();
+        });
+
+        builder.setNegativeButton("取消", (dialog, which) -> dialog.dismiss());
+
+        builder.show();
+    }
+
+    /**
+     * 合并两段文本
+     * 如果内容相同返回其中一个，不同则合并
+     */
+    private String mergeText(String local, String cloud) {
+        if (local == null || local.isEmpty()) return cloud;
+        if (cloud == null || cloud.isEmpty()) return local;
+        if (local.equals(cloud)) return local;
+
+        // 简单的合并策略：用分隔符连接
+        return local + "\n\n--- 云端版本 ---\n\n" + cloud;
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/ui/LoginActivity.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.ProgressBar;
+import android.widget.Toast;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.lifecycle.ViewModelProvider;
+
+import com.google.android.material.button.MaterialButton;
+import com.google.android.material.textfield.TextInputEditText;
+
+import net.micode.notes.R;
+import net.micode.notes.auth.UserAuthManager;
+import net.micode.notes.viewmodel.LoginViewModel;
+
+/**
+ * 登录界面
+ *
+ * <p>
+ * 提供用户登录和注册功能。
+ * 登录成功后，用户的笔记会自动同步到云端。
+ * </p>
+ * <p>
+ * 遵循 MVVM 架构，所有业务逻辑委托给 {@link LoginViewModel}。
+ * </p>
+ */
+public class LoginActivity extends AppCompatActivity {
+
+    private static final String TAG = "LoginActivity";
+
+    private TextInputEditText mEtUsername;
+    private TextInputEditText mEtPassword;
+    private MaterialButton mBtnLogin;
+    private MaterialButton mBtnRegister;
+    private View mTvSkip;
+    private ProgressBar mProgressBar;
+
+    private LoginViewModel mViewModel;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // 检查是否已经登录
+        UserAuthManager authManager = UserAuthManager.getInstance(this);
+        if (authManager.isLoggedIn()) {
+            startMainActivity();
+            return;
+        }
+
+        setContentView(R.layout.activity_login);
+
+        mViewModel = new ViewModelProvider(this).get(LoginViewModel.class);
+
+        initViews();
+        setupListeners();
+        observeViewModel();
+    }
+
+    private void initViews() {
+        mEtUsername = findViewById(R.id.et_username);
+        mEtPassword = findViewById(R.id.et_password);
+        mBtnLogin = findViewById(R.id.btn_login);
+        mBtnRegister = findViewById(R.id.btn_register);
+        mTvSkip = findViewById(R.id.tv_skip);
+        mProgressBar = findViewById(R.id.progress_bar);
+    }
+
+    private void setupListeners() {
+        mBtnLogin.setOnClickListener(v -> attemptLogin());
+        mBtnRegister.setOnClickListener(v -> attemptRegister());
+        mTvSkip.setOnClickListener(v -> skipLogin());
+    }
+
+    private void observeViewModel() {
+        mViewModel.getIsLoading().observe(this, isLoading -> showLoading(isLoading));
+
+        mViewModel.getErrorMessage().observe(this, error -> {
+            if (error != null) {
+                Toast.makeText(this, error, Toast.LENGTH_LONG).show();
+                mViewModel.clearError();
+            }
+        });
+
+        mViewModel.getLoginSuccess().observe(this, success -> {
+            if (success) {
+                Integer migratedCount = mViewModel.getMigratedNotesCount().getValue();
+                String message = (migratedCount != null && migratedCount > 0)
+                        ? "登录成功！已迁移 " + migratedCount + " 条本地笔记"
+                        : "登录成功！";
+                Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
+                startMainActivity();
+            }
+        });
+    }
+
+    private void attemptLogin() {
+        String username = mEtUsername.getText().toString().trim();
+        String password = mEtPassword.getText().toString().trim();
+        mViewModel.login(username, password);
+    }
+
+    private void attemptRegister() {
+        String username = mEtUsername.getText().toString().trim();
+        String password = mEtPassword.getText().toString().trim();
+        mViewModel.register(username, password);
+    }
+
+    private void skipLogin() {
+        Toast.makeText(this, "使用本地模式（不同步）", Toast.LENGTH_SHORT).show();
+        startMainActivity();
+    }
+
+    private void startMainActivity() {
+        Intent intent = new Intent(this, NotesListActivity.class);
+        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
+        startActivity(intent);
+        finish();
+    }
+
+    private void showLoading(boolean show) {
+        mProgressBar.setVisibility(show ? View.VISIBLE : View.GONE);
+        mBtnLogin.setEnabled(!show);
+        mBtnRegister.setEnabled(!show);
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/ui/NoteEditActivity.java

@@ -1449,10 +1449,33 @@ public class NoteEditActivity extends AppCompatActivity implements OnClickListen
              * {@link #RESULT_OK} is used to identify the create/edit state
              */
             setResult(RESULT_OK);
+
+            // 触发同步（如果用户已登录）
+            triggerBackgroundSync();
         }
         return saved;
     }
 
+    /**
+     * 触发后台同步（如果用户已登录）
+     */
+    private void triggerBackgroundSync() {
+        net.micode.notes.auth.UserAuthManager authManager = net.micode.notes.auth.UserAuthManager.getInstance(this);
+        if (authManager.isLoggedIn()) {
+            net.micode.notes.sync.SyncManager.getInstance().syncNotes(new net.micode.notes.sync.SyncManager.SyncCallback() {
+                @Override
+                public void onSuccess() {
+                    Log.d("NoteEditActivity", "Background sync completed after save");
+                }
+
+                @Override
+                public void onError(String error) {
+                    Log.e("NoteEditActivity", "Background sync failed after save: " + error);
+                }
+            });
+        }
+    }
+
     /**
      * 发送到桌面
      * <p>

src/Notesmaster/app/src/main/java/net/micode/notes/ui/NotesListActivity.java

@@ -18,9 +18,11 @@ package net.micode.notes.ui;
 
 import android.app.AlertDialog;
 import android.appwidget.AppWidgetManager;
+import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.os.Bundle;
 import android.text.InputFilter;
 import android.text.TextUtils;
@@ -48,9 +50,13 @@ import androidx.lifecycle.ViewModel;
 import androidx.lifecycle.ViewModelProvider;
 
 import net.micode.notes.R;
+import net.micode.notes.api.CloudCallback;
+import net.micode.notes.auth.UserAuthManager;
 import net.micode.notes.data.Notes;
+import net.micode.notes.sync.SyncManager;
 import net.micode.notes.data.NotesRepository;
 import net.micode.notes.databinding.NoteListBinding;
+import net.micode.notes.model.WorkingNote;
 import net.micode.notes.tool.SecurityManager;
 import net.micode.notes.ui.NoteInfoAdapter;
 import net.micode.notes.viewmodel.NotesListViewModel;
@@ -91,9 +97,30 @@ public class NotesListActivity extends AppCompatActivity
 
     // 多选模式状态
     private boolean isMultiSelectMode = false;
-    
+
     // 待打开的受保护笔记
     private long mPendingNodeIdToOpen = -1;
+
+    // 同步广播接收器
+    private BroadcastReceiver syncReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if ("com.micode.notes.ACTION_SYNC".equals(intent.getAction())) {
+                Log.d(TAG, "Received sync broadcast, triggering sync");
+                SyncManager.getInstance().syncNotes(new SyncManager.SyncCallback() {
+                    @Override
+                    public void onSuccess() {
+                        Log.d(TAG, "Auto-sync completed successfully");
+                    }
+
+                    @Override
+                    public void onError(String error) {
+                        Log.e(TAG, "Auto-sync failed: " + error);
+                    }
+                });
+            }
+        }
+    };
     private int mPendingNodeTypeToOpen = -1;
     private static final String KEY_PENDING_NODE_ID = "pending_node_id";
     private static final String KEY_PENDING_NODE_TYPE = "pending_node_type";
@@ -123,6 +150,14 @@ public class NotesListActivity extends AppCompatActivity
 
         initViewModel();
 
+        // 初始化SyncManager并设置冲突监听器
+        SyncManager.getInstance().initialize(this);
+        SyncManager.getInstance().setConflictListener(conflict -> {
+            runOnUiThread(() -> {
+                showConflictResolutionDialog(conflict);
+            });
+        });
+
         // 恢复 pending 状态和当前文件夹
         if (savedInstanceState != null) {
             mPendingNodeIdToOpen = savedInstanceState.getLong(KEY_PENDING_NODE_ID, -1);
@@ -165,6 +200,45 @@ public class NotesListActivity extends AppCompatActivity
         // 这样可以保证从 PasswordActivity 返回时，如果 onStart 先执行，不会重置为根目录
         viewModel.refreshNotes();
     }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+
+        // 注册同步广播接收器
+        IntentFilter filter = new IntentFilter("com.micode.notes.ACTION_SYNC");
+        registerReceiver(syncReceiver, filter);
+
+        // 切换到前台时触发同步（如果用户已登录）
+        UserAuthManager authManager = UserAuthManager.getInstance(this);
+        if (authManager.isLoggedIn()) {
+            long lastSync = SyncManager.getInstance().getLastSyncTime();
+            long currentTime = System.currentTimeMillis();
+            // 如果超过30分钟未同步，自动触发同步
+            if (currentTime - lastSync > 30 * 60 * 1000) {
+                Log.d(TAG, "Auto-syncing on resume (last sync: " + lastSync + ")");
+                SyncManager.getInstance().syncNotes(new SyncManager.SyncCallback() {
+                    @Override
+                    public void onSuccess() {
+                        Log.d(TAG, "Auto-sync on resume completed");
+                    }
+
+                    @Override
+                    public void onError(String error) {
+                        Log.e(TAG, "Auto-sync on resume failed: " + error);
+                    }
+                });
+            }
+        }
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+        // 注销同步广播接收器
+        unregisterReceiver(syncReceiver);
+    }
+
     private void initViewModel() {
         NotesRepository repository = new NotesRepository(getContentResolver());
         viewModel = new ViewModelProvider(this,
@@ -926,16 +1000,38 @@ public class NotesListActivity extends AppCompatActivity
 
     @Override
     public void onSyncSelected() {
-        // TODO: 实现同步功能
-        Log.d(TAG, "Sync selected");
-        Toast.makeText(this, "同步功能待实现", Toast.LENGTH_SHORT).show();
+        Log.d(TAG, "Sync selected, launching SyncActivity");
+        Intent intent = new Intent(this, SyncActivity.class);
+        startActivity(intent);
     }
 
     @Override
     public void onLoginSelected() {
-        // TODO: 实现登录功能
-        Log.d(TAG, "Login selected");
-        Toast.makeText(this, "登录功能待实现", Toast.LENGTH_SHORT).show();
+        Log.d(TAG, "Login selected, launching LoginActivity");
+        if (binding.drawerLayout != null) {
+            binding.drawerLayout.closeDrawer(sidebarFragment);
+        }
+        Intent intent = new Intent(this, LoginActivity.class);
+        startActivity(intent);
+    }
+
+    @Override
+    public void onLogoutSelected() {
+        Log.d(TAG, "Logout selected, user logged out");
+        if (binding.drawerLayout != null) {
+            binding.drawerLayout.closeDrawer(sidebarFragment);
+        }
+        refreshSidebar();
+        Toast.makeText(this, R.string.toast_logout_success, Toast.LENGTH_SHORT).show();
+    }
+
+    private void refreshSidebar() {
+        androidx.fragment.app.Fragment fragment = getSupportFragmentManager()
+                .findFragmentById(R.id.sidebar_fragment);
+        if (fragment instanceof SidebarFragment) {
+            ((SidebarFragment) fragment).updateUserState();
+            ((SidebarFragment) fragment).refreshFolderTree();
+        }
     }
 
     @Override
@@ -1229,6 +1325,127 @@ public class NotesListActivity extends AppCompatActivity
         }
     }
 
+    /**
+     * 显示冲突解决对话框
+     */
+    private void showConflictResolutionDialog(net.micode.notes.sync.Conflict conflict) {
+        try {
+            net.micode.notes.model.WorkingNote cloudWorkingNote = conflict.getCloudNote().toWorkingNote(this);
+            if (cloudWorkingNote == null) {
+                Log.e(TAG, "Failed to convert CloudNote to WorkingNote");
+                return;
+            }
+
+            ConflictResolutionDialog dialog = ConflictResolutionDialog.newInstance(
+                conflict.getLocalNote(),
+                cloudWorkingNote
+            );
+            dialog.setConflictResolutionListener(new ConflictResolutionDialog.ConflictResolutionListener() {
+                @Override
+                public void onChooseLocal() {
+                    handleConflictChoice(conflict, "local");
+                }
+
+                @Override
+                public void onChooseCloud() {
+                    handleConflictChoice(conflict, "cloud");
+                }
+
+                @Override
+                public void onMerge(String mergedTitle, String mergedContent) {
+                    handleConflictMerge(conflict, mergedTitle, mergedContent);
+                }
+            });
+            dialog.show(getSupportFragmentManager(), "conflict");
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to show conflict dialog", e);
+        }
+    }
+
+    /**
+     * 处理冲突合并
+     */
+    private void handleConflictMerge(net.micode.notes.sync.Conflict conflict, String mergedTitle, String mergedContent) {
+        net.micode.notes.auth.UserAuthManager authManager = net.micode.notes.auth.UserAuthManager.getInstance(this);
+        if (!authManager.isLoggedIn()) {
+            Toast.makeText(this, "未登录，无法同步", Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        // 更新本地笔记为合并后的内容
+        conflict.getLocalNote().setWorkingText(mergedContent);
+        conflict.getLocalNote().saveNote();
+
+        // 上传合并后的版本到云端
+        net.micode.notes.api.CloudDatabaseHelper cloudHelper = new net.micode.notes.api.CloudDatabaseHelper(
+            authManager.getUserId(),
+            authManager.getDeviceId(),
+            authManager.getAuthToken()
+        );
+
+        cloudHelper.uploadNote(conflict.getLocalNote(), new CloudCallback<String>() {
+            @Override
+            public void onSuccess(String result) {
+                runOnUiThread(() -> {
+                    Toast.makeText(NotesListActivity.this, "已合并并上传", Toast.LENGTH_SHORT).show();
+                    SyncManager.getInstance().removeConflict(conflict);
+                    viewModel.refreshNotes();
+                });
+            }
+
+            @Override
+            public void onError(String error) {
+                runOnUiThread(() -> {
+                    Toast.makeText(NotesListActivity.this, "合并上传失败: " + error, Toast.LENGTH_SHORT).show();
+                });
+            }
+        });
+    }
+
+    /**
+     * 处理用户对冲突的选择
+     */
+    private void handleConflictChoice(net.micode.notes.sync.Conflict conflict, String choice) {
+        net.micode.notes.auth.UserAuthManager authManager = net.micode.notes.auth.UserAuthManager.getInstance(this);
+        if (!authManager.isLoggedIn()) {
+            Toast.makeText(this, "未登录，无法同步", Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        net.micode.notes.api.CloudDatabaseHelper cloudHelper = new net.micode.notes.api.CloudDatabaseHelper(
+            authManager.getUserId(),
+            authManager.getDeviceId(),
+            authManager.getAuthToken()
+        );
+
+        if ("local".equals(choice)) {
+            cloudHelper.uploadNote(conflict.getLocalNote(), new CloudCallback<String>() {
+                @Override
+                public void onSuccess(String result) {
+                    runOnUiThread(() -> {
+                        Toast.makeText(NotesListActivity.this, "已上传本地版本", Toast.LENGTH_SHORT).show();
+                        SyncManager.getInstance().removeConflict(conflict);
+                        viewModel.refreshNotes();
+                    });
+                }
+
+                @Override
+                public void onError(String error) {
+                    runOnUiThread(() -> {
+                        Toast.makeText(NotesListActivity.this, "上传失败: " + error, Toast.LENGTH_SHORT).show();
+                    });
+                }
+            });
+        } else if ("cloud".equals(choice)) {
+            conflict.getLocalNote().updateFrom(conflict.getCloudNote());
+            runOnUiThread(() -> {
+                Toast.makeText(this, "已应用云端版本", Toast.LENGTH_SHORT).show();
+                SyncManager.getInstance().removeConflict(conflict);
+                viewModel.refreshNotes();
+            });
+        }
+    }
+
     @Override
     protected void onDestroy() {
         super.onDestroy();

src/Notesmaster/app/src/main/java/net/micode/notes/ui/SidebarFragment.java

@@ -18,15 +18,16 @@ package net.micode.notes.ui;
 
 import android.app.AlertDialog;
 import android.content.Context;
+import android.content.Intent;
 import android.os.Bundle;
 import android.text.InputFilter;
 import android.text.TextUtils;
+import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.view.animation.Animation;
-import android.view.animation.TranslateAnimation;
 import android.widget.EditText;
+import android.widget.ImageButton;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.PopupMenu;
@@ -41,21 +42,20 @@ import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import net.micode.notes.R;
+import net.micode.notes.auth.UserAuthManager;
 import net.micode.notes.data.Notes;
 import net.micode.notes.data.NotesRepository;
-import net.micode.notes.databinding.SidebarLayoutBinding;
+import net.micode.notes.sync.SyncManager;
 import net.micode.notes.viewmodel.FolderListViewModel;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
-import java.util.Set;
 
 /**
- * 侧栏Fragment
+ * 现代化侧边栏 Fragment - 自定义布局版
  * <p>
- * 显示文件夹树、菜单项和操作按钮
- * 提供文件夹导航、创建、展开/收起等功能
+ * 使用自定义 LinearLayout 替代 NavigationView
+ * 文件夹树在"文件夹"菜单项位置直接展开
  * </p>
  */
 public class SidebarFragment extends Fragment {
@@ -63,81 +63,52 @@ public class SidebarFragment extends Fragment {
     private static final String TAG = "SidebarFragment";
     private static final int MAX_FOLDER_NAME_LENGTH = 50;
 
-    // ViewBinding
-    private SidebarLayoutBinding binding;
-
-    // 适配器和数据
-    private FolderTreeAdapter adapter;
+    // 菜单项
+    private LinearLayout menuAllNotes;
+    private LinearLayout menuTrash;
+    private LinearLayout menuFolders;
+    private LinearLayout menuSyncSettings;
+    private LinearLayout menuTemplates;
+    private LinearLayout menuExport;
+    private LinearLayout menuSettings;
+    private LinearLayout menuLogin;
+    private LinearLayout menuLogout;
+
+    // 文件夹树
+    private LinearLayout folderTreeContainer;
+    private RecyclerView rvFolderTree;
+    private ImageButton btnCreateFolder;
+    private ImageView ivFolderExpand;
+
+    // 头部
+    private LinearLayout headerNotLoggedIn;
+    private LinearLayout headerLoggedIn;
+    private View btnLoginPrompt;
+    private TextView tvUsername;
+    private TextView tvDeviceId;
+
+    // ViewModel
     private FolderListViewModel viewModel;
-
-    // 单击和双击检测
-    private long lastClickTime = 0;
-    private View lastClickedView = null;
-    private static final long DOUBLE_CLICK_INTERVAL = 300; // 毫秒
+    private FolderTreeAdapter adapter;
 
     // 回调接口
     private OnSidebarItemSelectedListener listener;
 
-    /**
-     * 侧栏项选择回调接口
-     */
+    // 状态
+    private boolean isFolderTreeExpanded = false;
+
     public interface OnSidebarItemSelectedListener {
-        /**
-         * 跳转到指定文件夹
-         * @param folderId 文件夹ID
-         */
         void onFolderSelected(long folderId);
-
-        /**
-         * 打开回收站
-         */
         void onTrashSelected();
-
-        /**
-         * 同步
-         */
         void onSyncSelected();
-
-        /**
-         * 登录
-         */
         void onLoginSelected();
-
-        /**
-         * 导出
-         */
+        void onLogoutSelected();
         void onExportSelected();
-
-        /**
-         * 模板
-         */
         void onTemplateSelected();
-
-        /**
-         * 设置
-         */
         void onSettingsSelected();
-
-        /**
-         * 创建文件夹
-         */
         void onCreateFolder();
-
-        /**
-         * 关闭侧栏
-         */
         void onCloseSidebar();
-
-        /**
-         * 重命名文件夹
-         * @param folderId 文件夹ID
-         */
         void onRenameFolder(long folderId);
-
-        /**
-         * 删除文件夹
-         * @param folderId 文件夹ID
-         */
         void onDeleteFolder(long folderId);
     }
 
@@ -160,137 +131,146 @@ public class SidebarFragment extends Fragment {
     @Nullable
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
-                         @Nullable Bundle savedInstanceState) {
-        binding = SidebarLayoutBinding.inflate(inflater, container, false);
-        return binding.getRoot();
+                             @Nullable Bundle savedInstanceState) {
+        return inflater.inflate(R.layout.fragment_sidebar, container, false);
     }
 
     @Override
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
-        initViews();
-        setupListeners();
+        initViews(view);
+        initListeners();
+        initFolderTree();
         observeViewModel();
+        updateUserState();
     }
 
     @Override
-    public void onDestroyView() {
-        super.onDestroyView();
-        binding = null;
+    public void onResume() {
+        super.onResume();
+        updateUserState();
     }
 
-    /**
-     * 刷新文件夹树（供外部调用，如删除笔记后）
-     */
-    public void refreshFolderTree() {
-        if (viewModel != null) {
-            viewModel.loadFolderTree();
-        }
-    }
+    private void initViews(View view) {
+        // 头部
+        headerNotLoggedIn = view.findViewById(R.id.header_not_logged_in);
+        headerLoggedIn = view.findViewById(R.id.header_logged_in);
+        btnLoginPrompt = view.findViewById(R.id.btn_login_prompt);
+        tvUsername = view.findViewById(R.id.tv_username);
+        tvDeviceId = view.findViewById(R.id.tv_device_id);
 
-    /**
-     * 初始化视图
-     */
-    private void initViews() {
-        // 设置RecyclerView
-        binding.rvFolderTree.setLayoutManager(new LinearLayoutManager(requireContext()));
-        adapter = new FolderTreeAdapter(new ArrayList<>(), viewModel);
-        adapter.setOnFolderItemClickListener(this::handleFolderItemClick);
-        adapter.setOnFolderItemLongClickListener(this::handleFolderItemLongClick);
-        binding.rvFolderTree.setAdapter(adapter);
+        // 菜单项
+        menuAllNotes = view.findViewById(R.id.menu_all_notes);
+        menuTrash = view.findViewById(R.id.menu_trash);
+        menuFolders = view.findViewById(R.id.menu_folders);
+        menuSyncSettings = view.findViewById(R.id.menu_sync_settings);
+        menuTemplates = view.findViewById(R.id.menu_templates);
+        menuExport = view.findViewById(R.id.menu_export);
+        menuSettings = view.findViewById(R.id.menu_settings);
+        menuLogin = view.findViewById(R.id.menu_login);
+        menuLogout = view.findViewById(R.id.menu_logout);
+
+        // 文件夹树
+        folderTreeContainer = view.findViewById(R.id.folder_tree_container);
+        rvFolderTree = view.findViewById(R.id.rv_folder_tree);
+        btnCreateFolder = view.findViewById(R.id.btn_create_folder);
+        ivFolderExpand = view.findViewById(R.id.iv_folder_expand);
     }
 
-    /**
-     * 设置监听器
-     */
-    private void setupListeners() {
-        // 根文件夹（单击展开/收起，双击跳转）
-        setupFolderClickListener(binding.tvRootFolder, Notes.ID_ROOT_FOLDER);
+    private void initListeners() {
+        if (headerNotLoggedIn != null) {
+            headerNotLoggedIn.setOnClickListener(v -> {
+                if (listener != null) listener.onLoginSelected();
+            });
+        }
+        
+        if (headerLoggedIn != null) {
+            headerLoggedIn.setOnClickListener(v -> {
+                Log.d(TAG, "Logged in header clicked");
+            });
+        }
 
-        // 关闭侧栏
-        binding.btnCloseSidebar.setOnClickListener(v -> {
+        // 菜单项点击
+        menuAllNotes.setOnClickListener(v -> {
             if (listener != null) {
+                listener.onFolderSelected(Notes.ID_ROOT_FOLDER);
                 listener.onCloseSidebar();
             }
         });
 
-        // 创建文件夹
-        binding.btnCreateFolder.setOnClickListener(v -> showCreateFolderDialog());
-
-        // 菜单项
-        binding.menuSync.setOnClickListener(v -> {
+        menuTrash.setOnClickListener(v -> {
             if (listener != null) {
-                listener.onSyncSelected();
+                listener.onTrashSelected();
+                listener.onCloseSidebar();
             }
         });
 
-        binding.menuLogin.setOnClickListener(v -> {
-            if (listener != null) {
-                listener.onLoginSelected();
-            }
+        menuFolders.setOnClickListener(v -> toggleFolderTree());
+
+        menuSyncSettings.setOnClickListener(v -> {
+            Intent intent = new Intent(requireContext(), SyncActivity.class);
+            startActivity(intent);
+            if (listener != null) listener.onCloseSidebar();
         });
 
-        binding.menuExport.setOnClickListener(v -> {
+        menuTemplates.setOnClickListener(v -> {
             if (listener != null) {
-                listener.onExportSelected();
+                listener.onTemplateSelected();
+                listener.onCloseSidebar();
             }
         });
 
-        binding.menuTemplates.setOnClickListener(v -> {
+        menuExport.setOnClickListener(v -> {
             if (listener != null) {
-                listener.onTemplateSelected();
+                listener.onExportSelected();
+                listener.onCloseSidebar();
             }
         });
 
-        binding.menuSettings.setOnClickListener(v -> {
+        menuSettings.setOnClickListener(v -> {
             if (listener != null) {
                 listener.onSettingsSelected();
+                listener.onCloseSidebar();
             }
         });
 
-        binding.menuTrash.setOnClickListener(v -> {
+        menuLogin.setOnClickListener(v -> {
             if (listener != null) {
-                listener.onTrashSelected();
+                listener.onLoginSelected();
+                listener.onCloseSidebar();
             }
         });
+
+        menuLogout.setOnClickListener(v -> showLogoutConfirmDialog());
     }
 
-    /**
-     * 设置文件夹的单击/双击监听器
-     */
-    private void setupFolderClickListener(View view, long folderId) {
-        view.setOnClickListener(v -> {
-            android.util.Log.d(TAG, "setupFolderClickListener: folderId=" + folderId);
-            long currentTime = System.currentTimeMillis();
-            if (lastClickedView == view && (currentTime - lastClickTime) < DOUBLE_CLICK_INTERVAL) {
-                android.util.Log.d(TAG, "Double click on root folder, jumping to: " + folderId);
-                // 这是双击，执行跳转
-                if (listener != null) {
-                    // 根文件夹也可以跳转（回到根）
-                    listener.onFolderSelected(folderId);
-                }
-                // 重置双击状态
-                lastClickTime = 0;
-                lastClickedView = null;
-            } else {
-                android.util.Log.d(TAG, "Single click on root folder, will toggle expand in " + DOUBLE_CLICK_INTERVAL + "ms");
-                // 可能是单击，延迟处理
-                lastClickTime = currentTime;
-                lastClickedView = view;
-                view.postDelayed(() -> {
-                    // 如果在延迟期间没有发生双击，则执行单击操作（展开/收起）
-                    if (System.currentTimeMillis() - lastClickTime >= DOUBLE_CLICK_INTERVAL) {
-                        android.util.Log.d(TAG, "Toggling root folder expand");
-                        toggleFolderExpand(folderId);
-                    }
-                }, DOUBLE_CLICK_INTERVAL);
+    private void toggleFolderTree() {
+        isFolderTreeExpanded = !isFolderTreeExpanded;
+        folderTreeContainer.setVisibility(isFolderTreeExpanded ? View.VISIBLE : View.GONE);
+        
+        // 旋转展开图标
+        if (ivFolderExpand != null) {
+            ivFolderExpand.setRotation(isFolderTreeExpanded ? 180 : 0);
+        }
+    }
+
+    private void initFolderTree() {
+        rvFolderTree.setLayoutManager(new LinearLayoutManager(requireContext()));
+        adapter = new FolderTreeAdapter(new ArrayList<>(), viewModel);
+        adapter.setOnFolderItemClickListener(folderId -> {
+            if (listener != null) {
+                listener.onFolderSelected(folderId);
+                listener.onCloseSidebar();
             }
         });
+        adapter.setOnFolderItemLongClickListener(this::handleFolderItemLongClick);
+        rvFolderTree.setAdapter(adapter);
+
+        if (btnCreateFolder != null) {
+            btnCreateFolder.setOnClickListener(v -> showCreateFolderDialog());
+        }
     }
 
-    /**
-     * 观察ViewModel数据变化
-     */
     private void observeViewModel() {
         viewModel.getFolderTree().observe(getViewLifecycleOwner(), folderItems -> {
             if (folderItems != null) {
@@ -298,67 +278,73 @@ public class SidebarFragment extends Fragment {
                 adapter.notifyDataSetChanged();
             }
         });
-
         viewModel.loadFolderTree();
     }
 
-    /**
-     * 切换文件夹展开/收起状态
-     */
-    private void toggleFolderExpand(long folderId) {
-        android.util.Log.d(TAG, "toggleFolderExpand: folderId=" + folderId);
-        viewModel.toggleFolderExpand(folderId);
-    }
+    public void updateUserState() {
+        UserAuthManager authManager = UserAuthManager.getInstance(requireContext());
+        boolean isLoggedIn = authManager.isLoggedIn();
 
-    /**
-     * 处理文件夹项点击（单击/双击）
-     */
-    private void handleFolderItemClick(long folderId) {
-        android.util.Log.d(TAG, "handleFolderItemClick: folderId=" + folderId);
-        long currentTime = System.currentTimeMillis();
-        if (lastClickedFolderId == folderId && (currentTime - lastFolderClickTime) < DOUBLE_CLICK_INTERVAL) {
-            android.util.Log.d(TAG, "Double click detected, jumping to folder: " + folderId);
-            // 这是双击，执行跳转
-            if (listener != null) {
-                listener.onFolderSelected(folderId);
-            }
-            // 重置双击状态
-            lastFolderClickTime = 0;
-            lastClickedFolderId = -1;
-        } else {
-            android.util.Log.d(TAG, "Single click, will toggle expand in " + DOUBLE_CLICK_INTERVAL + "ms");
-            // 可能是单击，延迟处理
-            lastFolderClickTime = currentTime;
-            lastClickedFolderId = folderId;
-            new android.os.Handler().postDelayed(() -> {
-                // 如果在延迟期间没有发生双击，则执行单击操作（展开/收起）
-                if (System.currentTimeMillis() - lastFolderClickTime >= DOUBLE_CLICK_INTERVAL) {
-                    android.util.Log.d(TAG, "Toggling folder expand: " + folderId);
-                    toggleFolderExpand(folderId);
+        // 更新头部
+        if (headerNotLoggedIn != null && headerLoggedIn != null) {
+            if (isLoggedIn) {
+                headerNotLoggedIn.setVisibility(View.GONE);
+                headerLoggedIn.setVisibility(View.VISIBLE);
+
+                String username = authManager.getUsername();
+                String deviceId = authManager.getDeviceId();
+
+                if (tvUsername != null) {
+                    tvUsername.setText(username != null ? username : getString(R.string.drawer_default_username));
+                }
+                if (tvDeviceId != null) {
+                    tvDeviceId.setText(deviceId != null ? "Device: " + deviceId.substring(0, Math.min(8, deviceId.length()))
+                            : getString(R.string.drawer_default_device_id));
                 }
-            }, DOUBLE_CLICK_INTERVAL);
+            } else {
+                headerNotLoggedIn.setVisibility(View.VISIBLE);
+                headerLoggedIn.setVisibility(View.GONE);
+            }
+        }
+
+        // 更新菜单项
+        if (menuLogin != null && menuLogout != null) {
+            menuLogin.setVisibility(isLoggedIn ? View.GONE : View.VISIBLE);
+            menuLogout.setVisibility(isLoggedIn ? View.VISIBLE : View.GONE);
         }
     }
 
-    /**
-     * 处理文件夹项长按
-     */
-    private void handleFolderItemLongClick(long folderId) {
-        android.util.Log.d(TAG, "handleFolderItemLongClick: folderId=" + folderId);
-        // 检查是否是系统文件夹（根文件夹、回收站等不允许重命名/删除）
-        if (folderId <= 0) {
-            android.util.Log.d(TAG, "System folder, ignoring long press");
-            return;
+    private void showLogoutConfirmDialog() {
+        new AlertDialog.Builder(requireContext())
+                .setTitle(R.string.dialog_logout_title)
+                .setMessage(R.string.dialog_logout_message)
+                .setPositiveButton(R.string.dialog_logout_confirm, (dialog, which) -> performLogout())
+                .setNegativeButton(android.R.string.cancel, null)
+                .show();
+    }
+
+    private void performLogout() {
+        UserAuthManager authManager = UserAuthManager.getInstance(requireContext());
+        authManager.logout();
+
+        // 重置同步状态，清除上次同步时间
+        SyncManager.getInstance().resetSyncState();
+
+        updateUserState();
+
+        if (listener != null) {
+            listener.onLogoutSelected();
+            listener.onCloseSidebar();
         }
 
-        showFolderContextMenu(folderId);
+        Toast.makeText(requireContext(), R.string.toast_logout_success, Toast.LENGTH_SHORT).show();
+        Log.d(TAG, "User logged out successfully");
     }
 
-    /**
-     * 显示文件夹上下文菜单
-     */
-    private void showFolderContextMenu(long folderId) {
-        PopupMenu popup = new PopupMenu(requireContext(), binding.getRoot());
+    private void handleFolderItemLongClick(long folderId) {
+        if (folderId <= 0) return;
+        
+        PopupMenu popup = new PopupMenu(requireContext(), rvFolderTree);
         popup.getMenuInflater().inflate(R.menu.folder_context_menu, popup.getMenu());
 
         popup.setOnMenuItemClickListener(item -> {
@@ -370,8 +356,7 @@ public class SidebarFragment extends Fragment {
                 listener.onDeleteFolder(folderId);
                 return true;
             } else if (itemId == R.id.action_move) {
-                // TODO: 实现移动功能（阶段3）
-                Toast.makeText(requireContext(), "移动功能待实现", Toast.LENGTH_SHORT).show();
+                Toast.makeText(requireContext(), "移动功能开发中", Toast.LENGTH_SHORT).show();
                 return true;
             }
             return false;
@@ -380,14 +365,7 @@ public class SidebarFragment extends Fragment {
         popup.show();
     }
 
-    // 双击检测专用变量（针对文件夹列表项）
-    private long lastFolderClickTime = 0;
-    private long lastClickedFolderId = -1;
-
-    /**
-     * 显示创建文件夹对话框
-     */
-    private void showCreateFolderDialog() {
+    public void showCreateFolderDialog() {
         AlertDialog.Builder builder = new AlertDialog.Builder(requireContext());
         builder.setTitle(R.string.dialog_create_folder_title);
 
@@ -403,180 +381,153 @@ public class SidebarFragment extends Fragment {
                 Toast.makeText(requireContext(), R.string.error_folder_name_empty, Toast.LENGTH_SHORT).show();
                 return;
             }
-            if (folderName.length() > MAX_FOLDER_NAME_LENGTH) {
-                Toast.makeText(requireContext(), R.string.error_folder_name_too_long, Toast.LENGTH_SHORT).show();
-                return;
-            }
-
-            // 创建文件夹
-            NotesRepository repository = new NotesRepository(requireContext().getContentResolver());
-            long parentId = viewModel.getCurrentFolderId();
-            if (parentId == 0) {
-                parentId = Notes.ID_ROOT_FOLDER;
-            }
-            repository.createFolder(parentId, folderName,
-                new NotesRepository.Callback<Long>() {
-                    @Override
-                    public void onSuccess(Long folderId) {
-                        if (getActivity() != null) {
-                            getActivity().runOnUiThread(() -> {
-                                Toast.makeText(requireContext(), R.string.create_folder_success, Toast.LENGTH_SHORT).show();
-                                // 刷新文件夹列表
-                                viewModel.loadFolderTree();
-                            });
-                        }
-                    }
-
-                    @Override
-                    public void onError(Exception error) {
-                        if (getActivity() != null) {
-                            getActivity().runOnUiThread(() -> {
-                                Toast.makeText(requireContext(),
-                                        getString(R.string.error_folder_name_too_long) + ": " + error.getMessage(),
-                                        Toast.LENGTH_SHORT).show();
-                            });
-                        }
-                    }
-                });
+            createFolder(folderName);
         });
 
         builder.setNegativeButton(android.R.string.cancel, null);
         builder.show();
     }
 
-        /**
-         * FolderTreeAdapter
-         * 文件夹树适配器，支持层级显示和展开/收起
-         */
-        private static class FolderTreeAdapter extends RecyclerView.Adapter<FolderTreeAdapter.FolderViewHolder> {
-
-            private List<FolderTreeItem> folderItems;
-            private FolderListViewModel viewModel;
-            private OnFolderItemClickListener folderItemClickListener;
-            private OnFolderItemLongClickListener folderItemLongClickListener;
-
-            public FolderTreeAdapter(List<FolderTreeItem> folderItems, FolderListViewModel viewModel) {
-                this.folderItems = folderItems;
-                this.viewModel = viewModel;
+    private void createFolder(String folderName) {
+        NotesRepository repository = new NotesRepository(requireContext().getContentResolver());
+        long parentId = viewModel.getCurrentFolderId();
+        if (parentId == 0) parentId = Notes.ID_ROOT_FOLDER;
+        
+        repository.createFolder(parentId, folderName, new NotesRepository.Callback<Long>() {
+            @Override
+            public void onSuccess(Long folderId) {
+                if (getActivity() != null) {
+                    getActivity().runOnUiThread(() -> {
+                        Toast.makeText(requireContext(), R.string.create_folder_success, Toast.LENGTH_SHORT).show();
+                        viewModel.loadFolderTree();
+                    });
+                }
             }
 
-            public void setData(List<FolderTreeItem> folderItems) {
-                this.folderItems = folderItems;
+            @Override
+            public void onError(Exception error) {
+                if (getActivity() != null) {
+                    getActivity().runOnUiThread(() -> {
+                        Toast.makeText(requireContext(),
+                                getString(R.string.error_create_folder) + ": " + error.getMessage(),
+                                Toast.LENGTH_SHORT).show();
+                    });
+                }
             }
+        });
+    }
 
-            public void setOnFolderItemClickListener(OnFolderItemClickListener listener) {
-                this.folderItemClickListener = listener;
-            }
+    public void refreshFolderTree() {
+        if (viewModel != null) viewModel.loadFolderTree();
+    }
 
-            public void setOnFolderItemLongClickListener(OnFolderItemLongClickListener listener) {
-                this.folderItemLongClickListener = listener;
-            }
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        listener = null;
+    }
 
-            @NonNull
-            @Override
-            public FolderViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-                View view = LayoutInflater.from(parent.getContext())
-                        .inflate(R.layout.sidebar_folder_item, parent, false);
-                return new FolderViewHolder(view, folderItemClickListener, folderItemLongClickListener);
-            }
+    // ==================== FolderTreeAdapter ====================
 
-            @Override
-            public void onBindViewHolder(@NonNull FolderViewHolder holder, int position) {
-                FolderTreeItem item = folderItems.get(position);
-                boolean isExpanded = viewModel != null && viewModel.isFolderExpanded(item.folderId);
-                holder.bind(item, isExpanded);
-            }
+    private static class FolderTreeAdapter extends RecyclerView.Adapter<FolderTreeAdapter.FolderViewHolder> {
 
-            @Override
-            public int getItemCount() {
-                return folderItems.size();
-            }
+        private List<FolderTreeItem> folderItems;
+        private FolderListViewModel viewModel;
+        private OnFolderItemClickListener folderItemClickListener;
+        private OnFolderItemLongClickListener folderItemLongClickListener;
 
-            static class FolderViewHolder extends RecyclerView.ViewHolder {
-                private View indentView;
-                private ImageView ivExpandIcon;
-                private ImageView ivFolderIcon;
-                private TextView tvFolderName;
-                private TextView tvNoteCount;
-                private FolderTreeItem currentItem;
-                private final OnFolderItemClickListener folderItemClickListener;
-                private final OnFolderItemLongClickListener folderItemLongClickListener;
-
-                public FolderViewHolder(@NonNull View itemView, OnFolderItemClickListener clickListener,
-                                       OnFolderItemLongClickListener longClickListener) {
-                    super(itemView);
-                    this.folderItemClickListener = clickListener;
-                    this.folderItemLongClickListener = longClickListener;
-                    indentView = itemView.findViewById(R.id.indent_view);
-                    ivExpandIcon = itemView.findViewById(R.id.iv_expand_icon);
-                    ivFolderIcon = itemView.findViewById(R.id.iv_folder_icon);
-                    tvFolderName = itemView.findViewById(R.id.tv_folder_name);
-                    tvNoteCount = itemView.findViewById(R.id.tv_note_count);
-                }
+        public FolderTreeAdapter(List<FolderTreeItem> folderItems, FolderListViewModel viewModel) {
+            this.folderItems = folderItems;
+            this.viewModel = viewModel;
+        }
 
-                public void bind(FolderTreeItem item, boolean isExpanded) {
-                    this.currentItem = item;
+        public void setData(List<FolderTreeItem> folderItems) {
+            this.folderItems = folderItems;
+        }
 
-                    // 设置缩进
-                    int indent = item.level * 32;
-                    indentView.setLayoutParams(new LinearLayout.LayoutParams(indent, LinearLayout.LayoutParams.MATCH_PARENT));
+        public void setOnFolderItemClickListener(OnFolderItemClickListener listener) {
+            this.folderItemClickListener = listener;
+        }
 
-                    // 设置展开/收起图标
-                    if (item.hasChildren) {
-                        ivExpandIcon.setVisibility(View.VISIBLE);
-                        ivExpandIcon.setRotation(isExpanded ? 90 : 0);
-                    } else {
-                        ivExpandIcon.setVisibility(View.INVISIBLE);
+        public void setOnFolderItemLongClickListener(OnFolderItemLongClickListener listener) {
+            this.folderItemLongClickListener = listener;
+        }
+
+        @NonNull
+        @Override
+        public FolderViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+            View view = LayoutInflater.from(parent.getContext())
+                    .inflate(R.layout.sidebar_folder_item, parent, false);
+            return new FolderViewHolder(view, folderItemClickListener, folderItemLongClickListener);
+        }
+
+        @Override
+        public void onBindViewHolder(@NonNull FolderViewHolder holder, int position) {
+            FolderTreeItem item = folderItems.get(position);
+            boolean isExpanded = viewModel != null && viewModel.isFolderExpanded(item.folderId);
+            holder.bind(item, isExpanded);
+        }
+
+        @Override
+        public int getItemCount() {
+            return folderItems.size();
+        }
+
+        static class FolderViewHolder extends RecyclerView.ViewHolder {
+            private View indentView;
+            private View ivFolderIcon;
+            private TextView tvFolderName;
+            private TextView tvNoteCount;
+            private FolderTreeItem currentItem;
+
+            public FolderViewHolder(@NonNull View itemView, OnFolderItemClickListener clickListener,
+                                   OnFolderItemLongClickListener longClickListener) {
+                super(itemView);
+                indentView = itemView.findViewById(R.id.indent_view);
+                ivFolderIcon = itemView.findViewById(R.id.iv_folder_icon);
+                tvFolderName = itemView.findViewById(R.id.tv_folder_name);
+                tvNoteCount = itemView.findViewById(R.id.tv_note_count);
+
+                itemView.setOnClickListener(v -> {
+                    if (clickListener != null && currentItem != null) {
+                        clickListener.onFolderClick(currentItem.folderId);
                     }
+                });
 
-                    // 设置文件夹名称
-                    tvFolderName.setText(item.name);
+                itemView.setOnLongClickListener(v -> {
+                    if (longClickListener != null && currentItem != null) {
+                        longClickListener.onFolderLongClick(currentItem.folderId);
+                        return true;
+                    }
+                    return false;
+                });
+            }
 
-                    // 设置便签数量
-                    tvNoteCount.setText(String.format(itemView.getContext()
-                            .getString(R.string.folder_note_count), item.noteCount));
+            public void bind(FolderTreeItem item, boolean isExpanded) {
+                this.currentItem = item;
 
-                    // 设置点击监听器
-                    itemView.setOnClickListener(v -> {
-                        if (folderItemClickListener != null) {
-                            folderItemClickListener.onFolderClick(item.folderId);
-                        }
-                    });
+                int indent = item.level * 32;
+                indentView.setLayoutParams(new LinearLayout.LayoutParams(indent, LinearLayout.LayoutParams.MATCH_PARENT));
 
-                    // 设置长按监听器
-                    itemView.setOnLongClickListener(v -> {
-                        if (folderItemLongClickListener != null) {
-                            folderItemLongClickListener.onFolderLongClick(item.folderId);
-                            return true;
-                        }
-                        return false;
-                    });
-                }
+                tvFolderName.setText(item.name);
+                tvNoteCount.setText(String.format(itemView.getContext()
+                        .getString(R.string.folder_note_count), item.noteCount));
             }
         }
+    }
 
-        /**
-         * 文件夹项点击监听器接口
-         */
-        public interface OnFolderItemClickListener {
-            void onFolderClick(long folderId);
-        }
+    public interface OnFolderItemClickListener {
+        void onFolderClick(long folderId);
+    }
 
-        /**
-         * 文件夹项长按监听器接口
-         */
-        public interface OnFolderItemLongClickListener {
-            void onFolderLongClick(long folderId);
-        }
+    public interface OnFolderItemLongClickListener {
+        void onFolderLongClick(long folderId);
+    }
 
-    /**
-     * FolderTreeItem
-     * 文件夹树项数据模型
-     */
     public static class FolderTreeItem {
         public long folderId;
         public String name;
-        public int level; // 层级，0表示顶级
+        public int level;
         public boolean hasChildren;
         public int noteCount;
 
@@ -588,10 +539,4 @@ public class SidebarFragment extends Fragment {
             this.noteCount = noteCount;
         }
     }
-
-    @Override
-    public void onDetach() {
-        super.onDetach();
-        listener = null;
-    }
 }

src/Notesmaster/app/src/main/java/net/micode/notes/ui/SyncActivity.java

@@ -0,0 +1,154 @@
+/*
+ * 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.ui;
+
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import com.google.android.material.button.MaterialButton;
+import com.google.android.material.switchmaterial.SwitchMaterial;
+
+import net.micode.notes.R;
+import net.micode.notes.auth.UserAuthManager;
+import net.micode.notes.sync.SyncManager;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+
+/**
+ * 同步设置界面
+ * <p>
+ * 显示云同步设置，包括登录状态、同步开关、同步按钮和进度显示。
+ * </p>
+ */
+public class SyncActivity extends AppCompatActivity {
+
+    private static final String PREFS_SYNC = "sync_settings";
+    private static final String KEY_AUTO_SYNC = "auto_sync";
+    private static final String KEY_LAST_SYNC = "last_sync_time";
+
+    private TextView mTvDeviceId;
+    private TextView mTvLastSyncTime;
+    private TextView mTvSyncStatus;
+    private SwitchMaterial mSwitchAutoSync;
+    private ProgressBar mProgressSync;
+    private MaterialButton mBtnSyncNow;
+
+    private SharedPreferences mPrefs;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_sync);
+
+        mPrefs = getSharedPreferences(PREFS_SYNC, MODE_PRIVATE);
+
+        initViews();
+        loadSettings();
+    }
+
+    private void initViews() {
+        mTvDeviceId = findViewById(R.id.tv_device_id);
+        mTvLastSyncTime = findViewById(R.id.tv_last_sync_time);
+        mTvSyncStatus = findViewById(R.id.tv_sync_status);
+        mSwitchAutoSync = findViewById(R.id.switch_auto_sync);
+        mProgressSync = findViewById(R.id.progress_sync);
+        mBtnSyncNow = findViewById(R.id.btn_sync_now);
+
+        mSwitchAutoSync.setOnCheckedChangeListener((buttonView, isChecked) -> {
+            mPrefs.edit().putBoolean(KEY_AUTO_SYNC, isChecked).apply();
+        });
+
+        mBtnSyncNow.setOnClickListener(v -> startSync());
+    }
+
+    private void loadSettings() {
+        // Load auto sync setting
+        boolean autoSync = mPrefs.getBoolean(KEY_AUTO_SYNC, false);
+        mSwitchAutoSync.setChecked(autoSync);
+
+        // Load user info
+        UserAuthManager authManager = UserAuthManager.getInstance(this);
+        if (authManager.isLoggedIn()) {
+            String username = authManager.getUsername();
+            String deviceId = authManager.getDeviceId();
+            mTvDeviceId.setText("已登录: " + username + "\n设备ID: " + deviceId);
+        } else {
+            mTvDeviceId.setText("未登录，请先登录账号");
+            mBtnSyncNow.setEnabled(false);
+        }
+
+        // Load last sync time
+        long lastSync = mPrefs.getLong(KEY_LAST_SYNC, 0);
+        if (lastSync > 0) {
+            String timeStr = formatTime(lastSync);
+            mTvLastSyncTime.setText(timeStr);
+        }
+
+        // Set initial status
+        mTvSyncStatus.setText(R.string.sync_status_idle);
+    }
+
+    private void startSync() {
+        mTvSyncStatus.setText(R.string.sync_status_syncing);
+        mProgressSync.setVisibility(View.VISIBLE);
+        mBtnSyncNow.setEnabled(false);
+
+        Toast.makeText(this, R.string.sync_toast_started, Toast.LENGTH_SHORT).show();
+
+        SyncManager.getInstance().syncNotes(new SyncManager.SyncCallback() {
+            @Override
+            public void onSuccess() {
+                runOnUiThread(() -> {
+                    mTvSyncStatus.setText(R.string.sync_status_success);
+                    mProgressSync.setVisibility(View.INVISIBLE);
+                    mBtnSyncNow.setEnabled(true);
+
+                    long currentTime = System.currentTimeMillis();
+                    mPrefs.edit().putLong(KEY_LAST_SYNC, currentTime).apply();
+                    mTvLastSyncTime.setText(formatTime(currentTime));
+
+                    Toast.makeText(SyncActivity.this, R.string.sync_toast_success, Toast.LENGTH_SHORT).show();
+                });
+            }
+
+            @Override
+            public void onError(String error) {
+                runOnUiThread(() -> {
+                    mTvSyncStatus.setText(R.string.sync_status_failed);
+                    mProgressSync.setVisibility(View.INVISIBLE);
+                    mBtnSyncNow.setEnabled(true);
+
+                    String message = getString(R.string.sync_toast_failed, error);
+                    Toast.makeText(SyncActivity.this, message, Toast.LENGTH_LONG).show();
+                });
+            }
+        });
+    }
+
+    private String formatTime(long timeMillis) {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault());
+        return sdf.format(new Date(timeMillis));
+    }
+}

src/Notesmaster/app/src/main/java/net/micode/notes/viewmodel/LoginViewModel.java

@@ -0,0 +1,260 @@
+/*
+ * 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.viewmodel;
+
+import android.app.Application;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import net.micode.notes.auth.AnonymousAuthManager;
+import net.micode.notes.auth.UserAuthManager;
+import net.micode.notes.data.NotesRepository;
+import net.micode.notes.model.WorkingNote;
+import net.micode.notes.sync.SyncManager;
+
+import java.util.List;
+
+/**
+ * 登录界面 ViewModel
+ *
+ * <p>
+ * 管理登录相关的业务逻辑，包括用户认证、匿名数据迁移、首次登录全量同步等。
+ * 遵循 MVVM 架构，将业务逻辑从 Activity 中分离。
+ * </p>
+ * <p>
+ * 修复记录：
+ * 1. 修复登录后缺少全量下载的问题 - 登录后强制执行全量同步
+ * 2. 添加同步状态监听 - 同步完成后再通知登录成功
+ * 3. 优化匿名数据迁移流程 - 迁移后执行全量同步确保数据完整
+ * </p>
+ */
+public class LoginViewModel extends AndroidViewModel {
+
+    private static final String TAG = "LoginViewModel";
+
+    private final UserAuthManager mAuthManager;
+    private final AnonymousAuthManager mAnonymousAuthManager;
+    private final NotesRepository mNotesRepository;
+
+    private final MutableLiveData<Boolean> mIsLoading = new MutableLiveData<>(false);
+    private final MutableLiveData<String> mErrorMessage = new MutableLiveData<>();
+    private final MutableLiveData<Boolean> mLoginSuccess = new MutableLiveData<>(false);
+    private final MutableLiveData<Integer> mMigratedNotesCount = new MutableLiveData<>();
+    private final MutableLiveData<String> mSyncStatus = new MutableLiveData<>();
+
+    public LoginViewModel(@NonNull Application application) {
+        super(application);
+        mAuthManager = UserAuthManager.getInstance(application);
+        mAnonymousAuthManager = AnonymousAuthManager.getInstance(application);
+        mNotesRepository = new NotesRepository(application.getContentResolver());
+    }
+
+    public LiveData<Boolean> getIsLoading() {
+        return mIsLoading;
+    }
+
+    public LiveData<String> getErrorMessage() {
+        return mErrorMessage;
+    }
+
+    public LiveData<Boolean> getLoginSuccess() {
+        return mLoginSuccess;
+    }
+
+    public LiveData<Integer> getMigratedNotesCount() {
+        return mMigratedNotesCount;
+    }
+
+    public LiveData<String> getSyncStatus() {
+        return mSyncStatus;
+    }
+
+    /**
+     * 检查用户是否已登录
+     */
+    public boolean isLoggedIn() {
+        return mAuthManager.isLoggedIn();
+    }
+
+    /**
+     * 用户登录
+     */
+    public void login(String username, String password) {
+        if (username == null || username.isEmpty() || password == null || password.isEmpty()) {
+            mErrorMessage.setValue("请输入用户名和密码");
+            return;
+        }
+
+        mIsLoading.setValue(true);
+        mSyncStatus.setValue("正在登录...");
+
+        mAuthManager.login(username, password, new UserAuthManager.AuthCallback() {
+            @Override
+            public void onSuccess(String userId, String username) {
+                mSyncStatus.postValue("登录成功，正在同步数据...");
+                // 登录成功后执行数据迁移和全量同步
+                migrateAnonymousDataAndSync(userId);
+            }
+
+            @Override
+            public void onError(String error) {
+                mIsLoading.postValue(false);
+                mSyncStatus.postValue("登录失败");
+                mErrorMessage.postValue("登录失败: " + error);
+            }
+        });
+    }
+
+    /**
+     * 用户注册
+     */
+    public void register(String username, String password) {
+        if (username == null || username.isEmpty() || password == null || password.isEmpty()) {
+            mErrorMessage.setValue("请输入用户名和密码");
+            return;
+        }
+
+        if (password.length() < 6) {
+            mErrorMessage.setValue("密码长度至少6位");
+            return;
+        }
+
+        mIsLoading.setValue(true);
+        mSyncStatus.setValue("正在注册...");
+
+        mAuthManager.register(username, password, new UserAuthManager.AuthCallback() {
+            @Override
+            public void onSuccess(String userId, String username) {
+                mSyncStatus.postValue("注册成功，正在同步数据...");
+                // 注册成功后执行数据迁移和全量同步
+                migrateAnonymousDataAndSync(userId);
+            }
+
+            @Override
+            public void onError(String error) {
+                mIsLoading.postValue(false);
+                mSyncStatus.postValue("注册失败");
+                mErrorMessage.postValue("注册失败: " + error);
+            }
+        });
+    }
+
+    /**
+     * 新用户接管设备上的所有笔记并执行全量同步
+     *
+     * <p>关键逻辑：
+     * 1. 新用户接管设备上所有笔记（无论之前属于谁）
+     * 2. 将所有笔记标记为需要同步
+     * 3. 执行全量同步，上传到云端
+     * </p>
+     */
+    private void migrateAnonymousDataAndSync(String newUserId) {
+        mSyncStatus.postValue("正在接管设备上的笔记...");
+
+        // 新用户接管设备上所有笔记
+        mNotesRepository.takeoverAllNotes(newUserId, new NotesRepository.Callback<Integer>() {
+            @Override
+            public void onSuccess(Integer count) {
+                Log.d(TAG, "Takeover completed: " + count + " notes now belong to " + newUserId);
+                mMigratedNotesCount.postValue(count);
+                // 接管完成后执行全量同步（上传所有笔记到云端）
+                performFullSync();
+            }
+
+            @Override
+            public void onError(Exception error) {
+                Log.e(TAG, "Failed to takeover notes", error);
+                mMigratedNotesCount.postValue(0);
+                // 即使接管失败也尝试同步
+                performFullSync();
+            }
+        });
+    }
+
+    /**
+     * 执行全量同步
+     *
+     * <p>关键逻辑：
+     * 1. 首先上传设备上所有笔记到新用户的云端
+     * 2. 然后下载云端其他笔记（如果有）
+     * 这样新用户可以把设备上的所有内容都保存到云端。
+     * </p>
+     */
+    private void performFullSync() {
+        Log.d(TAG, "Performing full sync after login");
+        mSyncStatus.postValue("正在上传笔记到云端...");
+
+        // 初始化同步管理器
+        SyncManager.getInstance().initialize(getApplication());
+
+        // 重置同步状态
+        SyncManager.getInstance().resetSyncState();
+
+        // 第一步：上传所有本地笔记到云端
+        SyncManager.getInstance().uploadAllNotes(new SyncManager.SyncCallback() {
+            @Override
+            public void onSuccess() {
+                Log.d(TAG, "Upload all notes completed");
+                mSyncStatus.postValue("上传完成，正在下载云端笔记...");
+
+                // 第二步：下载云端其他笔记（如果有）
+                downloadCloudNotes();
+            }
+
+            @Override
+            public void onError(String error) {
+                Log.e(TAG, "Upload failed: " + error);
+                // 即使上传失败也尝试下载
+                downloadCloudNotes();
+            }
+        });
+    }
+
+    /**
+     * 下载云端笔记
+     */
+    private void downloadCloudNotes() {
+        SyncManager.getInstance().syncAllNotes(new SyncManager.SyncCallback() {
+            @Override
+            public void onSuccess() {
+                Log.d(TAG, "Download cloud notes completed");
+                mSyncStatus.postValue("同步完成");
+                mIsLoading.postValue(false);
+                mLoginSuccess.postValue(true);
+            }
+
+            @Override
+            public void onError(String error) {
+                Log.e(TAG, "Download failed: " + error);
+                mSyncStatus.postValue("同步完成（下载可能有部分失败）");
+                mIsLoading.postValue(false);
+                mLoginSuccess.postValue(true);
+            }
+        });
+    }
+
+    /**
+     * 清除错误消息
+     */
+    public void clearError() {
+        mErrorMessage.setValue(null);
+    }
+}

src/Notesmaster/app/src/main/res/drawable/drawer_header_circle_decorator.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Drawer Header Circle Decorator
+  装饰性圆形，用于增加层次感
+-->
+<shape xmlns:android="http://schemas.android.com/res/android"
+    android:shape="oval">
+
+    <solid android:color="@color/white" />
+
+</shape>

src/Notesmaster/app/src/main/res/drawable/drawer_header_gradient.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Drawer Header Gradient Background
+  蓝色系渐变背景，Material Design 3 风格
+-->
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+
+    <gradient
+        android:type="linear"
+        android:angle="135"
+        android:startColor="@color/drawer_header_gradient_start"
+        android:centerColor="@color/drawer_header_gradient_center"
+        android:endColor="@color/drawer_header_gradient_end"
+        android:centerX="0.3"
+        android:centerY="0.7" />
+
+    <corners android:radius="16dp" />
+
+</shape>

src/Notesmaster/app/src/main/res/drawable/ic_account_circle.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Account Circle Icon - Material Design 3
+  用户头像占位符
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="64dp"
+    android:height="64dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorPrimary">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM12,5c1.66,0 3,1.34 3,3s-1.34,3 -3,3 -3,-1.34 -3,-3 1.34,-3 3,-3zM12,19.2c-2.5,0 -4.71,-1.28 -6,-3.22 0.03,-1.99 4,-3.08 6,-3.08 1.99,0 5.97,1.09 6,3.08 -1.29,1.94 -3.5,3.22 -6,3.22z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_cloud_done.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Cloud Done Icon - Material Design 3
+  云同步完成图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="@color/white">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19.35,10.04C18.67,6.59 15.64,4 12,4C9.11,4 6.6,5.64 5.35,8.04C2.34,8.36 0,10.91 0,14c0,3.31 2.69,6 6,6h13c2.76,0 5,-2.24 5,-5C24,12.36 21.95,10.22 19.35,10.04zM10,17l-3.5,-3.5l1.41,-1.41L10,14.17l5.09,-5.09L16.5,10.5L10,17z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_cloud_settings.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Cloud Settings Icon - Material Design 3
+  云设置图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19.35,10.04C18.67,6.59 15.64,4 12,4C9.11,4 6.6,5.64 5.35,8.04C2.34,8.36 0,10.91 0,14c0,3.31 2.69,6 6,6h13c2.76,0 5,-2.24 5,-5C24,12.36 21.95,10.22 19.35,10.04zM19,18H6c-2.21,0 -4,-1.79 -4,-4c0,-2.05 1.53,-3.76 3.56,-3.97l1.07,-0.11l0.5,-0.95C8.08,7.14 9.94,6 12,6c2.62,0 4.88,1.86 5.39,4.43l0.3,1.5l1.53,0.11C20.78,12.14 22,13.45 22,15C22,16.65 20.65,18 19,18z" />
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M10.59,9.17L5.41,14.34 6.83,15.76 12.01,10.59z" />
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M13.41,9.17L12,10.59 17.18,15.76 18.59,14.34z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_delete.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Delete Icon - Material Design 3
+  删除/回收站图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_export.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Export Icon - Material Design 3
+  导出图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,9h-4V3H9v6H5l7,7 7,-7zM5,18v2h14v-2H5z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_favorite.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Favorite Icon - Material Design 3
+  收藏图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M12,21.35l-1.45,-1.32C5.4,15.36 2,12.28 2,8.5 2,5.42 4.42,3 7.5,3c1.74,0 3.41,0.81 4.5,2.09C13.09,3.81 14.76,3 16.5,3 19.58,3 22,5.42 22,8.5c0,3.78 -3.4,6.86 -8.55,11.54L12,21.35z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_help.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Help Icon - Material Design 3
+  帮助图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM13,19h-2v-2h2v2zM15.07,11.25l-0.9,0.92C13.45,12.9 13,13.5 13,15h-2v-0.5c0,-1.1 0.45,-2.1 1.17,-2.83l1.24,-1.26c0.37,-0.36 0.59,-0.86 0.59,-1.41 0,-1.1 -0.9,-2 -2,-2s-2,0.9 -2,2H8c0,-2.21 1.79,-4 4,-4s4,1.79 4,4c0,0.88 -0.36,1.68 -0.93,2.25z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_login.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Login Icon - Material Design 3
+  登录图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M10.3,7.7L10.3,7.7c-0.39,0.39 -0.39,1.01 0,1.4l1.9,1.9H3c-0.55,0 -1,0.45 -1,1v0c0,0.55 0.45,1 1,1h9.2l-1.9,1.9c-0.39,0.39 -0.39,1.01 0,1.4l0,0c0.39,0.39 1.01,0.39 1.4,0l3.59,-3.59c0.39,-0.39 0.39,-1.02 0,-1.41L11.7,7.7C11.31,7.31 10.69,7.31 10.3,7.7zM20,19h-7c-0.55,0 -1,0.45 -1,1v0c0,0.55 0.45,1 1,1h7c1.1,0 2,-0.9 2,-2V5c0,-1.1 -0.9,-2 -2,-2h-7c-0.55,0 -1,0.45 -1,1v0c0,0.55 0.45,1 1,1h7V19z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_logout.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Logout Icon - Material Design 3
+  退出登录图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M10.09,15.59L11.5,17l5,-5 -5,-5 -1.41,1.41L12.67,11H3v2h9.67l-2.58,2.59zM19,3H5c-1.11,0 -2,0.9 -2,2v4h2V5h14v14H5v-4H3v4c0,1.1 0.89,2 2,2h14c1.1,0 2,-0.9 2,-2V5c0,-1.1 -0.9,-2 -2,-2z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_notes.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Notes Icon - Material Design 3
+  笔记图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,3H5C3.9,3 3,3.9 3,5v14c0,1.1 0.9,2 2,2h14c1.1,0 2,-0.9 2,-2V5C21,3.9 20.1,3 19,3zM14,17H7v-2h7V17zM17,13H7v-2h10V13zM17,9H7V7h10V9z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_notes_logo.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Notes Logo - For Drawer Header
+  便签应用 Logo
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="72dp"
+    android:height="72dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="@color/white">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M14,2H6C4.9,2 4,2.9 4,4v16c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2V8L14,2zM16,18H8v-2h8V18zM16,14H8v-2h8V14zM13,9V3.5L18.5,9H13z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_reminder.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Reminder Icon - Material Design 3
+  提醒图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M18,16v-5c0,-3.07 -1.64,-5.64 -4.5,-6.32V4c0,-0.83 -0.67,-1.5 -1.5,-1.5S10.5,3.17 10.5,4v0.68C7.63,5.36 6,7.92 6,11v5l-2,2v1h16v-1L18,16zM13,16h-2v-2h2V16zM13,12h-2V8h2V12zM12,22c1.1,0 2,-0.9 2,-2h-4C10,21.1 10.9,22 12,22z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_settings.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Settings Icon - Material Design 3
+  设置图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19.14,12.94c0.04,-0.3 0.06,-0.61 0.06,-0.94c0,-0.32 -0.02,-0.64 -0.07,-0.94l2.03,-1.58c0.18,-0.14 0.23,-0.41 0.12,-0.61l-1.92,-3.32c-0.12,-0.22 -0.37,-0.29 -0.59,-0.22l-2.39,0.96c-0.5,-0.38 -1.03,-0.7 -1.62,-0.94L14.4,2.81c-0.04,-0.24 -0.24,-0.41 -0.48,-0.41h-3.84c-0.24,0 -0.43,0.17 -0.47,0.41L9.25,5.35C8.66,5.59 8.12,5.92 7.63,6.29L5.24,5.33c-0.22,-0.08 -0.47,0 -0.59,0.22L2.74,8.87C2.62,9.08 2.66,9.34 2.86,9.49l2.03,1.58C4.84,11.36 4.8,11.69 4.8,12s0.02,0.64 0.07,0.94l-2.03,1.58c-0.18,0.14 -0.23,0.41 -0.12,0.61l1.92,3.32c0.12,0.22 0.37,0.29 0.59,0.22l2.39,-0.96c0.5,0.38 1.03,0.7 1.62,0.94l0.36,2.54c0.05,0.24 0.24,0.41 0.48,0.41h3.84c0.24,0 0.44,-0.17 0.47,-0.41l0.36,-2.54c0.59,-0.24 1.13,-0.56 1.62,-0.94l2.39,0.96c0.22,0.08 0.47,0 0.59,-0.22l1.92,-3.32c0.12,-0.22 0.07,-0.47 -0.12,-0.61L19.14,12.94zM12,15.6c-1.98,0 -3.6,-1.62 -3.6,-3.6s1.62,-3.6 3.6,-3.6s3.6,1.62 3.6,3.6S13.98,15.6 12,15.6z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_sync.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Sync Icon - Material Design 3
+  同步图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M12,4V1L8,5l4,4V6c3.31,0 6,2.69 6,6c0,1.01 -0.25,1.97 -0.7,2.8l1.46,1.46C19.54,15.03 20,13.57 20,12C20,7.58 16.42,4 12,4zM12,18c-3.31,0 -6,-2.69 -6,-6c0,-1.01 0.25,-1.97 0.7,-2.8L5.24,7.74C4.46,8.97 4,10.43 4,12c0,4.42 3.58,8 8,8v3l4,-4l-4,-4V18z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/ic_template.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Template Icon - Material Design 3
+  模板图标
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorOnSurfaceVariant">
+
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M19,3H5C3.9,3 3,3.9 3,5v14c0,1.1 0.9,2 2,2h14c1.1,0 2,-0.9 2,-2V5C21,3.9 20.1,3 19,3zM7,7h10v2H7V7zM7,11h10v2H7V11zM7,15h7v2H7V15z" />
+
+</vector>

src/Notesmaster/app/src/main/res/drawable/online_status_indicator.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Online Status Indicator
+  在线状态指示器（绿色圆点）
+-->
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="oval">
+
+    <solid android:color="@color/drawer_online_status" />
+
+    <stroke
+        android:width="2dp"
+        android:color="@color/white" />
+
+</shape>

src/Notesmaster/app/src/main/res/layout/activity_login.xml

@@ -0,0 +1,100 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="24dp"
+    android:gravity="center">
+
+    <!-- Logo/Title -->
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="小米便签"
+        android:textSize="32sp"
+        android:textStyle="bold"
+        android:textColor="?attr/colorPrimary"
+        android:layout_marginBottom="8dp" />
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="账号登录"
+        android:textSize="18sp"
+        android:layout_marginBottom="32dp" />
+
+    <!-- Username Input -->
+    <com.google.android.material.textfield.TextInputLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="用户名"
+        style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
+        android:layout_marginBottom="16dp">
+
+        <com.google.android.material.textfield.TextInputEditText
+            android:id="@+id/et_username"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:inputType="text"
+            android:maxLines="1" />
+
+    </com.google.android.material.textfield.TextInputLayout>
+
+    <!-- Password Input -->
+    <com.google.android.material.textfield.TextInputLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="密码"
+        style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
+        app:endIconMode="password_toggle"
+        android:layout_marginBottom="24dp">
+
+        <com.google.android.material.textfield.TextInputEditText
+            android:id="@+id/et_password"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:inputType="textPassword"
+            android:maxLines="1" />
+
+    </com.google.android.material.textfield.TextInputLayout>
+
+    <!-- Progress Bar -->
+    <ProgressBar
+        android:id="@+id/progress_bar"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:visibility="gone"
+        android:layout_marginBottom="16dp" />
+
+    <!-- Login Button -->
+    <com.google.android.material.button.MaterialButton
+        android:id="@+id/btn_login"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="登录"
+        android:textSize="16sp"
+        app:cornerRadius="8dp"
+        android:layout_marginBottom="12dp" />
+
+    <!-- Register Button -->
+    <com.google.android.material.button.MaterialButton
+        android:id="@+id/btn_register"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="注册新账号"
+        android:textSize="16sp"
+        style="?attr/materialButtonOutlinedStyle"
+        app:cornerRadius="8dp"
+        android:layout_marginBottom="16dp" />
+
+    <!-- Skip Login -->
+    <TextView
+        android:id="@+id/tv_skip"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="暂不登录，使用本地模式"
+        android:textColor="?attr/colorPrimary"
+        android:padding="8dp" />
+
+</LinearLayout>

src/Notesmaster/app/src/main/res/layout/activity_sync.xml

@@ -0,0 +1,149 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="16dp">
+
+    <!-- Title -->
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/sync_title"
+        android:textSize="24sp"
+        android:textStyle="bold"
+        android:layout_marginBottom="16dp" />
+
+    <!-- Login Status Card -->
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        app:cardElevation="2dp"
+        app:cardCornerRadius="8dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp">
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_login_status"
+                android:textSize="16sp"
+                android:textStyle="bold" />
+
+            <TextView
+                android:id="@+id/tv_device_id"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_device_id_default"
+                android:textSize="14sp"
+                android:layout_marginTop="8dp" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+    <!-- Sync Settings -->
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        app:cardElevation="2dp"
+        app:cardCornerRadius="8dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp">
+
+            <!-- Auto Sync Switch -->
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical">
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:text="@string/sync_auto_sync"
+                    android:textSize="16sp" />
+
+                <com.google.android.material.switchmaterial.SwitchMaterial
+                    android:id="@+id/switch_auto_sync"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" />
+
+            </LinearLayout>
+
+            <View
+                android:layout_width="match_parent"
+                android:layout_height="1dp"
+                android:background="?android:attr/dividerVertical"
+                android:layout_marginVertical="12dp" />
+
+            <!-- Last Sync Time -->
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_last_time"
+                android:textSize="14sp" />
+
+            <TextView
+                android:id="@+id/tv_last_sync_time"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_never"
+                android:textSize="14sp"
+                android:layout_marginTop="4dp" />
+
+            <View
+                android:layout_width="match_parent"
+                android:layout_height="1dp"
+                android:background="?android:attr/dividerVertical"
+                android:layout_marginVertical="12dp" />
+
+            <!-- Sync Status -->
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_status_label"
+                android:textSize="14sp" />
+
+            <TextView
+                android:id="@+id/tv_sync_status"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/sync_status_idle"
+                android:textSize="14sp"
+                android:layout_marginTop="4dp" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+    <!-- Progress Bar -->
+    <ProgressBar
+        android:id="@+id/progress_sync"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        android:visibility="invisible"
+        style="?android:attr/progressBarStyleHorizontal" />
+
+    <!-- Sync Button -->
+    <com.google.android.material.button.MaterialButton
+        android:id="@+id/btn_sync_now"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/sync_button_now"
+        app:cornerRadius="8dp" />
+
+</LinearLayout>

src/Notesmaster/app/src/main/res/layout/dialog_conflict_resolution.xml

@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical"
+    android:padding="16dp">
+
+    <!-- Title -->
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/conflict_title"
+        android:textSize="20sp"
+        android:textStyle="bold"
+        android:layout_marginBottom="16dp" />
+
+    <!-- Local Version -->
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="12dp"
+        app:cardElevation="2dp"
+        app:cardCornerRadius="8dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="12dp">
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/conflict_local_version"
+                android:textSize="14sp"
+                android:textStyle="bold"
+                android:textColor="?attr/colorPrimary" />
+
+            <TextView
+                android:id="@+id/tv_local_content"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:textSize="14sp"
+                android:layout_marginTop="8dp"
+                android:maxLines="3"
+                android:ellipsize="end" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+    <!-- Cloud Version -->
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        app:cardElevation="2dp"
+        app:cardCornerRadius="8dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="12dp">
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/conflict_cloud_version"
+                android:textSize="14sp"
+                android:textStyle="bold"
+                android:textColor="?attr/colorSecondary" />
+
+            <TextView
+                android:id="@+id/tv_cloud_content"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:textSize="14sp"
+                android:layout_marginTop="8dp"
+                android:maxLines="3"
+                android:ellipsize="end" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+    <!-- Buttons -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <com.google.android.material.button.MaterialButton
+            android:id="@+id/btn_use_local"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:layout_marginEnd="4dp"
+            android:text="@string/conflict_use_local"
+            style="?attr/materialButtonOutlinedStyle" />
+
+        <com.google.android.material.button.MaterialButton
+            android:id="@+id/btn_use_cloud"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:layout_marginHorizontal="4dp"
+            android:text="@string/conflict_use_cloud"
+            style="?attr/materialButtonOutlinedStyle" />
+
+        <com.google.android.material.button.MaterialButton
+            android:id="@+id/btn_merge"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:layout_marginStart="4dp"
+            android:text="@string/conflict_merge"
+            android:enabled="false"
+            style="?attr/materialButtonOutlinedStyle" />
+
+    </LinearLayout>
+
+</LinearLayout>

src/Notesmaster/app/src/main/res/layout/drawer_folder_expand_icon.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  文件夹展开/收起图标
+-->
+<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/iv_expand_icon"
+    android:layout_width="24dp"
+    android:layout_height="24dp"
+    android:src="@android:drawable/ic_menu_more"
+    android:contentDescription="@string/folder_title"
+    android:layout_gravity="center_vertical" />

src/Notesmaster/app/src/main/res/layout/drawer_header.xml

@@ -0,0 +1,125 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Navigation Drawer Header Layout - Fixed Version
+  修复图标过大问题
+-->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/drawer_header_container"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical"
+    android:background="@drawable/drawer_header_gradient"
+    android:padding="12dp">
+
+    <!-- ========== 未登录状态 ========== -->
+    <LinearLayout
+        android:id="@+id/header_not_logged_in"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:gravity="center_vertical">
+
+        <!-- 应用 Logo -->
+        <ImageView
+            android:id="@+id/iv_app_logo"
+            android:layout_width="36dp"
+            android:layout_height="36dp"
+            android:src="@android:drawable/ic_menu_edit"
+            android:contentDescription="@string/app_name"
+            app:tint="@color/white" />
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:orientation="vertical"
+            android:layout_marginStart="12dp">
+
+            <!-- 应用名称 -->
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/app_name"
+                android:textColor="@color/white"
+                android:textSize="16sp"
+                android:textStyle="bold" />
+
+            <!-- 登录提示 -->
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/drawer_login_prompt"
+                android:textColor="@color/white"
+                android:textSize="12sp"
+                android:alpha="0.8" />
+
+        </LinearLayout>
+
+        <!-- 登录按钮 -->
+        <ImageButton
+            android:id="@+id/btn_login_prompt"
+            android:layout_width="32dp"
+            android:layout_height="32dp"
+            android:background="?attr/selectableItemBackgroundBorderless"
+            android:src="@drawable/ic_login"
+            android:contentDescription="@string/drawer_login"
+            app:tint="@color/white" />
+
+    </LinearLayout>
+
+    <!-- ========== 已登录状态 ========== -->
+    <LinearLayout
+        android:id="@+id/header_logged_in"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:gravity="center_vertical"
+        android:visibility="gone">
+
+        <!-- 用户头像 -->
+        <ImageView
+            android:id="@+id/iv_user_avatar"
+            android:layout_width="36dp"
+            android:layout_height="36dp"
+            android:src="@drawable/ic_account_circle"
+            android:background="@drawable/online_status_indicator"
+            app:tint="@color/white" />
+
+        <!-- 用户信息 -->
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:layout_marginStart="12dp"
+            android:orientation="vertical">
+
+            <!-- 用户名 -->
+            <TextView
+                android:id="@+id/tv_username"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/drawer_default_username"
+                android:textColor="@color/white"
+                android:textSize="14sp"
+                android:textStyle="bold"
+                android:maxLines="1"
+                android:ellipsize="end" />
+
+            <!-- 设备ID -->
+            <TextView
+                android:id="@+id/tv_device_id"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/drawer_default_device_id"
+                android:textColor="@color/white"
+                android:textSize="11sp"
+                android:alpha="0.8"
+                android:maxLines="1"
+                android:ellipsize="end" />
+
+        </LinearLayout>
+
+    </LinearLayout>
+
+</LinearLayout>

src/Notesmaster/app/src/main/res/layout/drawer_menu_divider.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Drawer Menu Divider
+  菜单分组分隔线
+-->
+<View xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="1dp"
+    android:layout_marginHorizontal="16dp"
+    android:layout_marginVertical="8dp"
+    android:background="?attr/colorOutlineVariant" />

src/Notesmaster/app/src/main/res/layout/fragment_sidebar.xml

@@ -0,0 +1,339 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Modern Sidebar Fragment Layout
+  使用自定义布局替代 NavigationView，支持菜单项间插入文件夹树
+-->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:background="?attr/colorSurface"
+    android:fitsSystemWindows="true">
+
+    <!-- 头部 -->
+    <include layout="@layout/drawer_header" />
+
+    <!-- 可滚动的菜单区域 -->
+    <androidx.core.widget.NestedScrollView
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical">
+
+            <!-- 全部笔记 -->
+            <LinearLayout
+                android:id="@+id/menu_all_notes"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_notes"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/drawer_all_notes"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 回收站 -->
+            <LinearLayout
+                android:id="@+id/menu_trash"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_delete"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/menu_trash"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 文件夹（可点击展开）-->
+            <LinearLayout
+                android:id="@+id/menu_folders"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@android:drawable/ic_menu_myplaces"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/folder_title"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+                <ImageView
+                    android:id="@+id/iv_folder_expand"
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@android:drawable/ic_menu_more"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+            </LinearLayout>
+
+            <!-- 文件夹树（默认隐藏，点击文件夹后展开）-->
+            <LinearLayout
+                android:id="@+id/folder_tree_container"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="vertical"
+                android:visibility="gone">
+
+                <LinearLayout
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:orientation="horizontal"
+                    android:gravity="center_vertical"
+                    android:paddingHorizontal="16dp"
+                    android:paddingVertical="8dp">
+
+                    <TextView
+                        android:layout_width="0dp"
+                        android:layout_height="wrap_content"
+                        android:layout_weight="1"
+                        android:layout_marginStart="40dp"
+                        android:text="@string/folder_title"
+                        android:textSize="12sp"
+                        android:textStyle="bold"
+                        android:textColor="?attr/colorOnSurfaceVariant" />
+
+                    <ImageButton
+                        android:id="@+id/btn_create_folder"
+                        android:layout_width="32dp"
+                        android:layout_height="32dp"
+                        android:background="?attr/selectableItemBackgroundBorderless"
+                        android:src="@android:drawable/ic_input_add"
+                        android:contentDescription="@string/menu_create_folder"
+                        app:tint="?attr/colorPrimary" />
+
+                </LinearLayout>
+
+                <androidx.recyclerview.widget.RecyclerView
+                    android:id="@+id/rv_folder_tree"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:maxHeight="200dp"
+                    android:clipToPadding="false"
+                    android:layout_marginStart="40dp" />
+
+            </LinearLayout>
+
+            <!-- 同步设置 -->
+            <LinearLayout
+                android:id="@+id/menu_sync_settings"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_cloud_settings"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/drawer_sync_settings"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 模板 -->
+            <LinearLayout
+                android:id="@+id/menu_templates"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_template"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/menu_templates"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 导出 -->
+            <LinearLayout
+                android:id="@+id/menu_export"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_export"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/menu_export"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 设置 -->
+            <LinearLayout
+                android:id="@+id/menu_settings"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_settings"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/menu_settings"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 登录 -->
+            <LinearLayout
+                android:id="@+id/menu_login"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_login"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/drawer_login"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+            <!-- 退出登录（默认隐藏）-->
+            <LinearLayout
+                android:id="@+id/menu_logout"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingHorizontal="16dp"
+                android:paddingVertical="12dp"
+                android:background="?attr/selectableItemBackground"
+                android:visibility="gone">
+
+                <ImageView
+                    android:layout_width="24dp"
+                    android:layout_height="24dp"
+                    android:src="@drawable/ic_logout"
+                    app:tint="?attr/colorOnSurfaceVariant" />
+
+                <TextView
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="16dp"
+                    android:text="@string/drawer_logout"
+                    android:textSize="14sp"
+                    android:textColor="?attr/colorOnSurface" />
+
+            </LinearLayout>
+
+        </LinearLayout>
+
+    </androidx.core.widget.NestedScrollView>
+
+</LinearLayout>

src/Notesmaster/app/src/main/res/layout/sidebar_folder_item.xml

@@ -18,22 +18,11 @@
         android:layout_width="0dp"
         android:layout_height="match_parent" />
 
-    <!-- 展开/收起箭头 -->
+    <!-- 文件夹图标（兼展开/收起功能） -->
     <ImageView
-        android:id="@+id/iv_expand_icon"
+        android:id="@+id/iv_folder_icon"
         android:layout_width="24dp"
         android:layout_height="24dp"
-        android:src="@android:drawable/arrow_down_float"
-        android:contentDescription="展开/收起"
-        android:scaleType="centerInside"
-        android:rotation="0" />
-
-    <!-- 文件夹图标 -->
-    <ImageView
-        android:id="@+id/iv_folder_icon"
-        android:layout_width="32dp"
-        android:layout_height="32dp"
-        android:layout_marginStart="8dp"
         android:src="@android:drawable/ic_menu_myplaces"
         android:contentDescription="文件夹"
         android:scaleType="centerInside" />

src/Notesmaster/app/src/main/res/menu/drawer_menu.xml

@@ -0,0 +1,92 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Navigation Drawer Menu - Simplified
+  移除分隔线，简化菜单项
+-->
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <!-- ========== 笔记相关 ========== -->
+    <group
+        android:id="@+id/group_notes"
+        android:checkableBehavior="single">
+
+        <item
+            android:id="@+id/nav_all_notes"
+            android:icon="@drawable/ic_notes"
+            android:title="@string/drawer_all_notes"
+            android:checked="true" />
+
+        <item
+            android:id="@+id/nav_trash"
+            android:icon="@drawable/ic_delete"
+            android:title="@string/menu_trash" />
+
+    </group>
+
+    <!-- ========== 文件夹（可折叠）========== -->
+    <group
+        android:id="@+id/group_folders"
+        android:checkableBehavior="none">
+
+        <item
+            android:id="@+id/nav_folders"
+            android:icon="@android:drawable/ic_menu_more"
+            android:title="@string/folder_title"
+            app:actionLayout="@layout/drawer_folder_expand_icon" />
+
+    </group>
+
+    <!-- ========== 云同步 ========== -->
+    <group
+        android:id="@+id/group_sync"
+        android:checkableBehavior="none">
+
+        <item
+            android:id="@+id/nav_sync_settings"
+            android:icon="@drawable/ic_cloud_settings"
+            android:title="@string/drawer_sync_settings" />
+
+    </group>
+
+    <!-- ========== 其他 ========== -->
+    <group
+        android:id="@+id/group_other"
+        android:checkableBehavior="none">
+
+        <item
+            android:id="@+id/nav_templates"
+            android:icon="@drawable/ic_template"
+            android:title="@string/menu_templates" />
+
+        <item
+            android:id="@+id/nav_export"
+            android:icon="@drawable/ic_export"
+            android:title="@string/menu_export" />
+
+        <item
+            android:id="@+id/nav_settings"
+            android:icon="@drawable/ic_settings"
+            android:title="@string/menu_settings" />
+
+    </group>
+
+    <!-- ========== 账户操作 ========== -->
+    <group
+        android:id="@+id/group_account"
+        android:checkableBehavior="none">
+
+        <item
+            android:id="@+id/nav_login"
+            android:icon="@drawable/ic_login"
+            android:title="@string/drawer_login" />
+
+        <item
+            android:id="@+id/nav_logout"
+            android:icon="@drawable/ic_logout"
+            android:title="@string/drawer_logout"
+            android:visible="false" />
+
+    </group>
+
+</menu>

src/Notesmaster/app/src/main/res/values/colors.xml

@@ -42,4 +42,11 @@
     <color name="bg_eye_care_green">#C7EDCC</color>
     <color name="bg_warm">#FFE0B2</color>
     <color name="bg_cool">#E1BEE7</color>
+
+    <!-- Drawer Header Colors - Material Design 3 Blue Theme -->
+    <color name="drawer_header_gradient_start">#1976D2</color>
+    <color name="drawer_header_gradient_center">#2196F3</color>
+    <color name="drawer_header_gradient_end">#64B5F6</color>
+    <color name="drawer_online_status">#4CAF50</color>
+    <color name="drawer_sync_status_bg">#1AFFFFFF</color>
 </resources>

src/Notesmaster/app/src/main/res/values/strings.xml

@@ -190,4 +190,59 @@
     <string name="menu_rich_text">Rich Text</string>
     <string name="menu_restore">Restore</string>
     <string name="menu_permanent_delete">Delete Forever</string>
+
+    <!-- Drawer Navigation -->
+    <string name="drawer_login_prompt">点击登录/注册</string>
+    <string name="drawer_default_username">用户</string>
+    <string name="drawer_default_device_id">Device ID: Unknown</string>
+    <string name="drawer_sync_status_synced">已同步</string>
+    <string name="drawer_sync_status_syncing">同步中...</string>
+    <string name="drawer_sync_status_failed">同步失败</string>
+    <string name="drawer_group_notes">笔记</string>
+    <string name="drawer_group_sync">云同步</string>
+    <string name="drawer_group_other">其他</string>
+    <string name="drawer_all_notes">全部笔记</string>
+    <string name="drawer_favorites">收藏</string>
+    <string name="drawer_reminders">提醒</string>
+    <string name="drawer_sync_now">立即同步</string>
+    <string name="drawer_sync_settings">同步设置</string>
+    <string name="drawer_help">帮助与反馈</string>
+    <string name="drawer_login">登录</string>
+    <string name="drawer_logout">退出登录</string>
+
+    <!-- Cloud Sync -->
+    <string name="sync_title">Cloud Sync</string>
+    <string name="sync_login_status">Login Status</string>
+    <string name="sync_device_id_default">Device ID: Not initialized</string>
+    <string name="sync_auto_sync">Auto Sync</string>
+    <string name="sync_last_time">Last Sync Time:</string>
+    <string name="sync_never">Never</string>
+    <string name="sync_status_label">Sync Status:</string>
+    <string name="sync_status_idle">Idle</string>
+    <string name="sync_status_syncing">Syncing...</string>
+    <string name="sync_status_success">Sync Successful</string>
+    <string name="sync_status_failed">Sync Failed</string>
+    <string name="sync_button_now">Sync Now</string>
+    <string name="sync_toast_started">Sync started</string>
+    <string name="sync_toast_success">Sync completed successfully</string>
+    <string name="sync_toast_failed">Sync failed: %1$s</string>
+
+    <!-- Logout -->
+    <string name="dialog_logout_title">退出登录</string>
+    <string name="dialog_logout_message">确定要退出登录吗？退出后本地笔记将保留，但无法同步到云端。</string>
+    <string name="dialog_logout_confirm">退出</string>
+    <string name="toast_logout_success">已退出登录</string>
+
+    <!-- Folder -->
+    <string name="folder_title">文件夹</string>
+    <string name="error_create_folder">创建文件夹失败</string>
+
+    <!-- Conflict Resolution -->
+    <string name="conflict_title">Note Conflict</string>
+    <string name="conflict_local_version">Local Version</string>
+    <string name="conflict_cloud_version">Cloud Version</string>
+    <string name="conflict_use_local">Use Local</string>
+    <string name="conflict_use_cloud">Use Cloud</string>
+    <string name="conflict_merge">Merge</string>
+    <string name="conflict_merge_hint">Merge feature coming soon</string>
 </resources>

src/Notesmaster/app/src/main/res/values/styles.xml

@@ -65,4 +65,10 @@
     <style name="NoteActionBarStyle" parent="@android:style/Widget.Holo.Light.ActionBar.Solid">
         <item name="android:visibility">visible</item>
     </style>
+
+    <!-- Drawer Navigation Styles -->
+    <style name="CircleImageView" parent="">
+        <item name="cornerFamily">rounded</item>
+        <item name="cornerSize">50%</item>
+    </style>
 </resources>

src/Notesmaster/app/src/test/java/net/micode/notes/model/CloudNoteTest.java

@@ -0,0 +1,70 @@
+package net.micode.notes.model;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import static org.junit.Assert.*;
+
+/**
+ * CloudNote单元测试
+ */
+@RunWith(RobolectricTestRunner.class)
+public class CloudNoteTest {
+
+    @Test
+    public void testCloudNoteFromJson() throws JSONException {
+        // 测试从JSON解析cloudNoteId
+        JSONObject json = new JSONObject();
+        json.put("cloudNoteId", "test-uuid-123");
+        json.put("noteId", "100");
+        json.put("title", "测试标题");
+        json.put("content", "测试内容");
+        json.put("parentId", "0");
+        json.put("type", 0);
+        json.put("modifiedTime", 1234567890L);
+
+        CloudNote cloudNote = new CloudNote(json);
+
+        assertEquals("test-uuid-123", cloudNote.getCloudNoteId());
+        assertEquals("100", cloudNote.getNoteId());
+        assertEquals("测试标题", cloudNote.getTitle());
+    }
+
+    @Test
+    public void testCloudNoteToJson() throws JSONException {
+        // 创建模拟的WorkingNote
+        WorkingNote note = WorkingNote.createEmptyNote(
+            RuntimeEnvironment.getApplication(), 
+            0, 
+            0, 
+            -1, 
+            0
+        );
+        note.setTitle("测试标题");
+        note.setContent("测试内容");
+        note.setCloudNoteId("test-uuid-456");
+
+        CloudNote cloudNote = new CloudNote(note, "device-123");
+        JSONObject json = cloudNote.toJson();
+
+        assertEquals("test-uuid-456", json.getString("cloudNoteId"));
+        assertEquals("测试标题", json.getString("title"));
+    }
+
+    @Test
+    public void testCloudNoteWithoutCloudNoteId() throws JSONException {
+        // 测试没有cloudNoteId的情况（首次上传）
+        JSONObject json = new JSONObject();
+        json.put("noteId", "200");
+        json.put("title", "新笔记");
+
+        CloudNote cloudNote = new CloudNote(json);
+
+        assertEquals("", cloudNote.getCloudNoteId());
+        assertEquals("200", cloudNote.getNoteId());
+    }
+}

src/Notesmaster/settings.gradle.kts

@@ -16,6 +16,9 @@ dependencyResolutionManagement {
     repositories {
         google()
         mavenCentral()
+        maven { url = uri("https://maven.aliyun.com/repository/public") }
+        maven { url = uri("https://maven.aliyun.com/repository/gradle-plugin") }
+        maven { url = uri("https://maven.aliyun.com/repository/releases") }
     }
 }