注释

src/ActionFailureException.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.exception;
+
+/**
+ * ActionFailureException 类是用于表示操作失败时抛出的异常。
+ * 它继承自 RuntimeException，因此它是一个非检查型异常（unchecked exception），
+ * 这意味着在方法签名中不需要声明此异常可能会被抛出。
+ */
+public class ActionFailureException extends RuntimeException {
+
+    // 序列化版本唯一标识符，用于确保类的不同版本之间的兼容性。
+    private static final long serialVersionUID = 4425249765923293627L;
+
+    /**
+     * 构造一个没有详细信息消息和原因的 ActionFailureException。
+     */
+    public ActionFailureException() {
+        super();
+    }
+
+    /**
+     * 使用指定的详细信息消息构造一个新的 ActionFailureException。
+     * @param paramString 提供更多关于异常的信息的消息字符串。
+     */
+    public ActionFailureException(String paramString) {
+        super(paramString);
+    }
+
+    /**
+     * 使用指定的详细信息消息和原因构造一个新的 ActionFailureException。
+     * @param paramString 提供更多关于异常的信息的消息字符串。
+     * @param paramThrowable 导致当前异常的底层原因。
+     */
+    public ActionFailureException(String paramString, Throwable paramThrowable) {
+        super(paramString, paramThrowable);
+    }
+}

src/GTaskASyncTask.java

@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.os.AsyncTask;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesListActivity;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+/**
+ * GTaskASyncTask 类用于异步执行Google任务（GTask）同步操作。
+ * 它继承自 AsyncTask，以便在后台线程中执行耗时的网络操作，
+ * 并通过主线程更新用户界面或发送通知。
+ */
+public class GTaskASyncTask extends AsyncTask<Void, String, Integer> {
+
+    // 用于同步操作的通知ID，确保唯一性。
+    private static final int GTASK_SYNC_NOTIFICATION_ID = 5234235;
+
+    /**
+     * 当同步完成时调用的接口。
+     */
+    public interface OnCompleteListener {
+        void onComplete();
+    }
+
+    // 上下文对象，用于访问应用资源和系统服务。
+    private Context mContext;
+
+    // 管理通知的服务。
+    private NotificationManager mNotifiManager;
+
+    // 负责管理与Google任务交互的任务管理器。
+    private GTaskManager mTaskManager;
+
+    // 同步完成后调用的监听器。
+    private OnCompleteListener mOnCompleteListener;
+
+    /**
+     * 构造一个新的 GTaskASyncTask 实例。
+     * @param context 应用上下文。
+     * @param listener 同步完成后的回调监听器。
+     */
+    public GTaskASyncTask(Context context, OnCompleteListener listener) {
+        mContext = context;
+        mOnCompleteListener = listener;
+        mNotifiManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
+        mTaskManager = GTaskManager.getInstance();
+    }
+
+    /**
+     * 取消正在进行的同步操作。
+     */
+    public void cancelSync() {
+        mTaskManager.cancelSync();
+    }
+
+    /**
+     * 更新进度信息。
+     * @param message 进度消息文本。
+     */
+    public void publishProgess(String message) {
+        publishProgress(new String[]{message});
+    }
+
+    /**
+     * 显示一个通知给用户。
+     * @param tickerId 通知栏提示文字的资源ID。
+     * @param content 通知内容文本。
+     */
+    private void showNotification(int tickerId, String content) {
+        Notification notification = new Notification(R.drawable.notification, 
+                                                     mContext.getString(tickerId), 
+                                                     System.currentTimeMillis());
+        notification.defaults = Notification.DEFAULT_LIGHTS;
+        notification.flags = Notification.FLAG_AUTO_CANCEL;
+        
+        // 根据同步结果选择不同的PendingIntent
+        PendingIntent pendingIntent;
+        if (tickerId != R.string.ticker_success) {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, 
+                new Intent(mContext, NotesPreferenceActivity.class), 0);
+        } else {
+            pendingIntent = PendingIntent.getActivity(mContext, 0, 
+                new Intent(mContext, NotesListActivity.class), 0);
+        }
+        
+        // 设置通知详情，并显示通知
+        notification.setLatestEventInfo(mContext, mContext.getString(R.string.app_name), content, pendingIntent);
+        mNotifiManager.notify(GTASK_SYNC_NOTIFICATION_ID, notification);
+    }
+
+    /**
+     * 在后台线程中执行的实际同步逻辑。
+     */
+    @Override
+    protected Integer doInBackground(Void... unused) {
+        // 发布登录进度信息
+        publishProgess(mContext.getString(R.string.sync_progress_login, 
+                                          NotesPreferenceActivity.getSyncAccountName(mContext)));
+        // 执行同步操作并返回状态码
+        return mTaskManager.sync(mContext, this);
+    }
+
+    /**
+     * 更新UI线程上的进度。
+     */
+    @Override
+    protected void onProgressUpdate(String... progress) {
+        // 显示同步中的通知
+        showNotification(R.string.ticker_syncing, progress[0]);
+        // 如果上下文是GTaskSyncService，则广播进度信息
+        if (mContext instanceof GTaskSyncService) {
+            ((GTaskSyncService) mContext).sendBroadcast(progress[0]);
+        }
+    }
+
+    /**
+     * 同步完成后，在UI线程上执行此方法。
+     */
+    @Override
+    protected void onPostExecute(Integer result) {
+        // 根据同步结果显示不同通知
+        switch(result) {
+            case GTaskManager.STATE_SUCCESS:
+                showNotification(R.string.ticker_success, 
+                                 mContext.getString(R.string.success_sync_account, mTaskManager.getSyncAccount()));
+                NotesPreferenceActivity.setLastSyncTime(mContext, System.currentTimeMillis());
+                break;
+            case GTaskManager.STATE_NETWORK_ERROR:
+                showNotification(R.string.ticker_fail, 
+                                 mContext.getString(R.string.error_sync_network));
+                break;
+            case GTaskManager.STATE_INTERNAL_ERROR:
+                showNotification(R.string.ticker_fail, 
+                                 mContext.getString(R.string.error_sync_internal));
+                break;
+            case GTaskManager.STATE_SYNC_CANCELLED:
+                showNotification(R.string.ticker_cancel, 
+                                 mContext.getString(R.string.error_sync_cancelled));
+                break;
+        }
+        
+        // 如果存在监听器，则启动新线程调用onComplete方法
+        if (mOnCompleteListener != null) {
+            new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    mOnCompleteListener.onComplete();
+                }
+            }).start();
+        }
+    }
+}

src/GTaskClient.java

@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.accounts.AccountManagerFuture;
+import android.app.Activity;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.gtask.data.Node;
+import net.micode.notes.gtask.data.Task;
+import net.micode.notes.gtask.data.TaskList;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.gtask.exception.NetworkFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.ClientProtocolException;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.cookie.Cookie;
+import org.apache.http.impl.client.BasicCookieStore;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.params.BasicHttpParams;
+import org.apache.http.params.HttpConnectionParams;
+import org.apache.http.params.HttpParams;
+import org.apache.http.params.HttpProtocolParams;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.Inflater;
+import java.util.zip.InflaterInputStream;
+
+// GTaskClient 类用于与 Google Tasks 进行交互，主要包含任务和任务列表的创建、删除、修改等操作
+public class GTaskClient {
+    private static final String TAG = GTaskClient.class.getSimpleName();
+
+    // 定义 GTASK 的 URL 地址
+    private static final String GTASK_URL = "https://mail.google.com/tasks/";
+    private static final String GTASK_GET_URL = "https://mail.google.com/tasks/ig";
+    private static final String GTASK_POST_URL = "https://mail.google.com/tasks/r/ig";
+
+    private static GTaskClient mInstance = null; // 单例对象
+    private DefaultHttpClient mHttpClient;  // HTTP 客户端
+    private String mGetUrl;  // GET 请求 URL
+    private String mPostUrl;  // POST 请求 URL
+    private long mClientVersion;  // 客户端版本
+    private boolean mLoggedin;  // 登录状态
+    private long mLastLoginTime;  // 上次登录时间
+    private int mActionId;  // 操作 ID，用于唯一标识每个操作
+    private Account mAccount;  // 当前登录的 Google 帐号
+    private JSONArray mUpdateArray;  // 更新操作数组
+
+    // 私有化构造方法，避免外部实例化
+    private GTaskClient() {
+        mHttpClient = null;
+        mGetUrl = GTASK_GET_URL;
+        mPostUrl = GTASK_POST_URL;
+        mClientVersion = -1;
+        mLoggedin = false;
+        mLastLoginTime = 0;
+        mActionId = 1;
+        mAccount = null;
+        mUpdateArray = null;
+    }
+
+    // 单例模式获取 GTaskClient 实例
+    public static synchronized GTaskClient getInstance() {
+        if (mInstance == null) {
+            mInstance = new GTaskClient();
+        }
+        return mInstance;
+    }
+
+    // 登录方法，返回是否成功
+    public boolean login(Activity activity) {
+        // 每 5 分钟重新登录一次
+        final long interval = 1000 * 60 * 5;
+        if (mLastLoginTime + interval < System.currentTimeMillis()) {
+            mLoggedin = false;
+        }
+
+        // 如果切换了帐号，也需要重新登录
+        if (mLoggedin && !TextUtils.equals(getSyncAccount().name, NotesPreferenceActivity.getSyncAccountName(activity))) {
+            mLoggedin = false;
+        }
+
+        if (mLoggedin) {
+            Log.d(TAG, "已经登录");
+            return true;
+        }
+
+        mLastLoginTime = System.currentTimeMillis();
+        String authToken = loginGoogleAccount(activity, false);
+        if (authToken == null) {
+            Log.e(TAG, "Google 帐号登录失败");
+            return false;
+        }
+
+        // 如果是自定义域名帐号，需要构建对应的 URL
+        if (!(mAccount.name.toLowerCase().endsWith("gmail.com") || mAccount.name.toLowerCase().endsWith("googlemail.com"))) {
+            StringBuilder url = new StringBuilder(GTASK_URL).append("a/");
+            int index = mAccount.name.indexOf('@') + 1;
+            String suffix = mAccount.name.substring(index);
+            url.append(suffix + "/");
+            mGetUrl = url.toString() + "ig";
+            mPostUrl = url.toString() + "r/ig";
+
+            if (tryToLoginGtask(activity, authToken)) {
+                mLoggedin = true;
+            }
+        }
+
+        // 尝试使用 Google 官方 URL 登录
+        if (!mLoggedin) {
+            mGetUrl = GTASK_GET_URL;
+            mPostUrl = GTASK_POST_URL;
+            if (!tryToLoginGtask(activity, authToken)) {
+                return false;
+            }
+        }
+
+        mLoggedin = true;
+        return true;
+    }
+
+    // 获取授权令牌
+    private String loginGoogleAccount(Activity activity, boolean invalidateToken) {
+        String authToken;
+        AccountManager accountManager = AccountManager.get(activity);
+        Account[] accounts = accountManager.getAccountsByType("com.google");
+
+        if (accounts.length == 0) {
+            Log.e(TAG, "没有可用的 Google 帐号");
+            return null;
+        }
+
+        // 根据设置中的帐号名称来选择帐户
+        String accountName = NotesPreferenceActivity.getSyncAccountName(activity);
+        Account account = null;
+        for (Account a : accounts) {
+            if (a.name.equals(accountName)) {
+                account = a;
+                break;
+            }
+        }
+        if (account != null) {
+            mAccount = account;
+        } else {
+            Log.e(TAG, "无法找到相同名称的帐户");
+            return null;
+        }
+
+        // 获取授权令牌
+        AccountManagerFuture<Bundle> accountManagerFuture = accountManager.getAuthToken(account, "goanna_mobile", null, activity, null, null);
+        try {
+            Bundle authTokenBundle = accountManagerFuture.getResult();
+            authToken = authTokenBundle.getString(AccountManager.KEY_AUTHTOKEN);
+            if (invalidateToken) {
+                accountManager.invalidateAuthToken("com.google", authToken);
+                loginGoogleAccount(activity, false);
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "获取授权令牌失败");
+            authToken = null;
+        }
+
+        return authToken;
+    }
+
+    // 尝试登录 Google 任务
+    private boolean tryToLoginGtask(Activity activity, String authToken) {
+        if (!loginGtask(authToken)) {
+            // 如果授权令牌过期，重新登录
+            authToken = loginGoogleAccount(activity, true);
+            if (authToken == null) {
+                Log.e(TAG, "Google 帐号登录失败");
+                return false;
+            }
+
+            if (!loginGtask(authToken)) {
+                Log.e(TAG, "登录 Google Tasks 失败");
+                return false;
+            }
+        }
+        return true;
+    }
+
+    // 通过授权令牌登录 Google Tasks
+    private boolean loginGtask(String authToken) {
+        int timeoutConnection = 10000;
+        int timeoutSocket = 15000;
+        HttpParams httpParameters = new BasicHttpParams();
+        HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
+        HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
+        mHttpClient = new DefaultHttpClient(httpParameters);
+        BasicCookieStore localBasicCookieStore = new BasicCookieStore();
+        mHttpClient.setCookieStore(localBasicCookieStore);
+        HttpProtocolParams.setUseExpectContinue(mHttpClient.getParams(), false);
+
+        // 登录 Google 任务
+        try {
+            String loginUrl = mGetUrl + "?auth=" + authToken;
+            HttpGet httpGet = new HttpGet(loginUrl);
+            HttpResponse response = mHttpClient.execute(httpGet);
+
+            // 获取 Cookie
+            List<Cookie> cookies = mHttpClient.getCookieStore().getCookies();
+            boolean hasAuthCookie = false;
+            for (Cookie cookie : cookies) {
+                if (cookie.getName().contains("GTL")) {
+                    hasAuthCookie = true;
+                }
+            }
+            if (!hasAuthCookie) {
+                Log.w(TAG, "未找到授权 Cookie");
+            }
+
+            // 获取客户端版本
+            String resString = getResponseContent(response.getEntity());
+            String jsBegin = "_setup(";
+            String jsEnd = ");";
+
+            int beginIndex = resString.indexOf(jsBegin);
+            int endIndex = resString.indexOf(jsEnd);
+            if (beginIndex != -1 && endIndex != -1) {
+                String jsonString = resString.substring(beginIndex + jsBegin.length(), endIndex);
+                JSONObject jsonObject = new JSONObject(jsonString);
+                mClientVersion = jsonObject.optLong("clientVersion", -1);
+            }
+            return true;
+        } catch (Exception e) {
+            Log.e(TAG, "登录失败：" + e.getMessage());
+            return false;
+        }
+    }
+
+    // 获取 HTTP 响应内容
+    private String getResponseContent(HttpEntity entity) throws IOException {
+        InputStream inputStream = entity.getContent();
+        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
+        StringBuilder stringBuilder = new StringBuilder();
+        String line;
+        while ((line = bufferedReader.readLine()) != null) {
+            stringBuilder.append(line).append("\n");
+        }
+        return stringBuilder.toString();
+    }
+
+    // 获取当前同步的 Google 帐号
+    public Account getSyncAccount() {
+        return mAccount;
+    }
+
+    // 获取已登录状态
+    public boolean isLoggedin() {
+        return mLoggedin;
+    }
+}

src/GTaskManager.java

@@ -0,0 +1,805 @@
+/*
+ * Copyright (c) 2010 - 2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.app.Activity;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.data.MetaData;
+import net.micode.notes.gtask.data.Node;
+import net.micode.notes.gtask.data.SqlNote;
+import net.micode.notes.gtask.data.Task;
+import net.micode.notes.gtask.data.TaskList;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.gtask.exception.NetworkFailureException;
+import net.micode.notes.tool.DataUtils;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+
+// GTaskManager类用于管理与Google Task的同步操作等相关功能
+public class GTaskManager {
+    private static final String TAG = GTaskManager.class.getSimpleName();
+
+    // 同步成功状态码
+    public static final int STATE_SUCCESS = 0;
+    // 网络错误状态码
+    public static final int STATE_NETWORK_ERROR = 1;
+    // 内部错误状态码
+    public static final int STATE_INTERNAL_ERROR = 2;
+    // 同步正在进行状态码
+    public static final int STATE_SYNC_IN_PROGRESS = 3;
+    // 同步已取消状态码
+    public static final int STATE_SYNC_CANCELLED = 4;
+
+    private static GTaskManager mInstance = null;
+
+    // 关联的Activity，用于获取认证令牌等操作
+    private Activity mActivity;
+    // 上下文对象
+    private Context mContext;
+    // 内容解析器，用于操作内容提供器相关数据
+    private ContentResolver mContentResolver;
+    // 标记是否正在同步
+    private boolean mSyncing;
+    // 标记同步是否已取消
+    private boolean mCancelled;
+    // 存储Google Task列表的哈希表，以任务列表的GID为键，对应的TaskList对象为值
+    private HashMap<String, TaskList> mGTaskListHashMap;
+    // 存储Google Task节点的哈希表，以任务的GID为键，对应的Node对象为值
+    private HashMap<String, Node> mGTaskHashMap;
+    // 存储元数据的哈希表，以相关GID为键，对应的MetaData对象为值
+    private HashMap<String, MetaData> mMetaHashMap;
+    // 元数据列表对象
+    private TaskList mMetaList;
+    // 存储本地要删除的记录的ID集合
+    private HashSet<Long> mLocalDeleteIdMap;
+    // 存储Google任务的GID到本地记录ID的映射关系
+    private HashMap<String, Long> mGidToNid;
+    // 存储本地记录ID到Google任务的GID的映射关系
+    private HashMap<Long, String> mNidToGid;
+
+    // 私有构造函数，用于初始化相关成员变量
+    private GTaskManager() {
+        mSyncing = false;
+        mCancelled = false;
+        mGTaskListHashMap = new HashMap<String, TaskList>();
+        mGTaskHashMap = new HashMap<String, Node>();
+        mMetaHashMap = new HashMap<String, MetaData>();
+        mMetaList = null;
+        mLocalDeleteIdMap = new HashSet<Long>();
+        mGidToNid = new HashMap<String, Long>();
+        mNidToGid = new HashMap<Long, String>();
+    }
+
+    // 获取GTaskManager的单例实例
+    public static synchronized GTaskManager getInstance() {
+        if (mInstance == null) {
+            mInstance = new GTaskManager();
+        }
+        return mInstance;
+    }
+
+    // 设置关联的Activity上下文，主要用于获取认证令牌等操作
+    public synchronized void setActivityContext(Activity activity) {
+        // used for getting authtoken
+        mActivity = activity;
+    }
+
+    // 执行同步操作的核心方法，根据不同情况进行与Google Task的同步流程
+    public int sync(Context context, GTaskASyncTask asyncTask) {
+        if (mSyncing) {
+            Log.d(TAG, "Sync is in progress");
+            return STATE_SYNC_IN_PROGRESS;
+        }
+        mContext = context;
+        mContentResolver = mContext.getContentResolver();
+        mSyncing = true;
+        mCancelled = false;
+        // 清除之前同步相关的数据缓存
+        mGTaskListHashMap.clear();
+        mGTaskHashMap.clear();
+        mMetaHashMap.clear();
+        mLocalDeleteIdMap.clear();
+        mGidToNid.clear();
+        mNidToGid.clear();
+
+        try {
+            GTaskClient client = GTaskClient.getInstance();
+            client.resetUpdateArray();
+
+            // 登录Google Task，如果取消则不执行登录操作，登录失败抛出网络异常
+            if (!mCancelled) {
+                if (!client.login(mActivity)) {
+                    throw new NetworkFailureException("login google task failed");
+                }
+            }
+
+            // 发布初始化任务列表的进度提示
+            asyncTask.publishProgess(mContext.getString(R.string.sync_progress_init_list));
+            initGTaskList();
+
+            // 发布正在同步内容的进度提示
+            asyncTask.publishProgess(mContext.getString(R.string.sync_progress_syncing));
+            syncContent();
+        } catch (NetworkFailureException e) {
+            Log.e(TAG, e.toString());
+            return STATE_NETWORK_ERROR;
+        } catch (ActionFailureException e) {
+            Log.e(TAG, e.toString());
+            return STATE_INTERNAL_ERROR;
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return STATE_INTERNAL_ERROR;
+        } finally {
+            // 无论如何，最终都要清除同步相关的数据缓存，并重置同步状态
+            mGTaskListHashMap.clear();
+            mGTaskHashMap.clear();
+            mMetaHashMap.clear();
+            mLocalDeleteIdMap.clear();
+            mGidToNid.clear();
+            mNidToGid.clear();
+            mSyncing = false;
+        }
+
+        return mCancelled? STATE_SYNC_CANCELLED : STATE_SUCCESS;
+    }
+
+    // 初始化Google Task列表，从Google获取任务列表信息并进行相关处理
+    private void initGTaskList() throws NetworkFailureException {
+        if (mCancelled)
+            return;
+        GTaskClient client = GTaskClient.getInstance();
+        try {
+            // 获取Google Task列表的JSON数组表示
+            JSONArray jsTaskLists = client.getTaskLists();
+
+            // 先初始化元数据列表，查找特定名称的元数据列表
+            mMetaList = null;
+            for (int i = 0; i < jsTaskLists.length(); i++) {
+                JSONObject object = jsTaskLists.getJSONObject(i);
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                String name = object.getString(GTaskStringUtils.GTASK_JSON_NAME);
+
+                if (name.equals(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_META)) {
+                    mMetaList = new TaskList();
+                    mMetaList.setContentByRemoteJSON(object);
+
+                    // 加载元数据，获取对应任务列表下的元数据数组并逐个处理
+                    JSONArray jsMetas = client.getTaskList(gid);
+                    for (int j = 0; j < jsMetas.length(); j++) {
+                        object = (JSONObject) jsMetas.getJSONObject(j);
+                        MetaData metaData = new MetaData();
+                        metaData.setContentByRemoteJSON(object);
+                        if (metaData.isWorthSaving()) {
+                            mMetaList.addChildTask(metaData);
+                            if (metaData.getGid()!= null) {
+                                mMetaHashMap.put(metaData.getRelatedGid(), metaData);
+                            }
+                        }
+                    }
+                }
+            }
+
+            // 如果元数据列表不存在，则创建一个新的元数据列表并上传到Google
+            if (mMetaList == null) {
+                mMetaList = new TaskList();
+                mMetaList.setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_META);
+                GTaskClient.getInstance().createTaskList(mMetaList);
+            }
+
+            // 初始化常规任务列表，遍历任务列表数组，创建并填充TaskList对象以及其包含的Task对象
+            for (int i = 0; i < jsTaskLists.length(); i++) {
+                JSONObject object = jsTaskLists.getJSONObject(i);
+                String gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                String name = object.getString(GTaskStringUtils.GTASK_JSON_NAME);
+
+                if (name.startsWith(GTaskStringUtils.MIUI_FOLDER_PREFFIX) &&
+                       !name.equals(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_META)) {
+                    TaskList tasklist = new TaskList();
+                    tasklist.setContentByRemoteJSON(object);
+                    mGTaskListHashMap.put(gid, tasklist);
+                    mGTaskHashMap.put(gid, tasklist);
+
+                    // 加载任务，获取对应任务列表下的任务数组并逐个处理
+                    JSONArray jsTasks = client.getTaskList(gid);
+                    for (int j = 0; j < jsTasks.length(); j++) {
+                        object = (JSONObject) jsTasks.getJSONObject(j);
+                        gid = object.getString(GTaskStringUtils.GTASK_JSON_ID);
+                        Task task = new Task();
+                        task.setContentByRemoteJSON(object);
+                        if (task.isWorthSaving()) {
+                            task.setMetaInfo(mMetaHashMap.get(gid));
+                            tasklist.addChildTask(task);
+                            mGTaskHashMap.put(gid, task);
+                        }
+                    }
+                }
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("initGTaskList: handing JSONObject failed");
+        }
+    }
+
+    // 同步内容的主要方法，协调本地和远程数据的同步操作
+    private void syncContent() throws NetworkFailureException {
+        int syncType;
+        Cursor c = null;
+        String gid;
+        Node node;
+
+        mLocalDeleteIdMap.clear();
+
+        if (mCancelled) {
+            return;
+        }
+
+        // 处理本地已删除的笔记，查询本地已删除笔记并与远程数据对比进行相应同步操作
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type<>? AND parent_id=?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, null);
+            if (c!= null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node!= null) {
+                        mGTaskHashMap.remove(gid);
+                        doContentSync(Node.SYNC_ACTION_DEL_REMOTE, node, c);
+                    }
+
+                    mLocalDeleteIdMap.add(c.getLong(SqlNote.ID_COLUMN));
+                }
+            } else {
+                Log.w(TAG, "failed to query trash folder");
+            }
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // 同步文件夹相关数据
+        syncFolder();
+
+        // 处理数据库中已存在的笔记，查询并根据情况确定同步类型，然后执行相应同步操作
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type=? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_NOTE), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c!= null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node!= null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, c.getLong(SqlNote.ID_COLUMN));
+                        mNidToGid.put(c.getLong(SqlNote.ID_COLUMN), gid);
+                        syncType = node.getSyncAction(c);
+                    } else {
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {
+                            // 本地新增情况
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;
+                        } else {
+                            // 远程删除情况
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;
+                        }
+                    }
+                    doContentSync(syncType, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query existing note in database");
+            }
+
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // 处理剩余的未处理的任务，进行添加本地任务的同步操作
+        Iterator<Map.Entry<String, Node>> iter = mGTaskHashMap.entrySet().iterator();
+        while (iter.hasNext()) {
+            Map.Entry<String, Node> entry = iter.next();
+            node = entry.getValue();
+            doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);
+        }
+
+        // 如果未取消同步，清除本地已删除的记录
+        // mCancelled可以被其他线程设置，所以需要逐个检查
+        if (!mCancelled) {
+            if (!DataUtils.batchDeleteNotes(mContentResolver, mLocalDeleteIdMap)) {
+                throw new ActionFailureException("failed to batch-delete local deleted notes");
+            }
+        }
+
+        // 如果未取消同步，提交更新并刷新本地同步ID
+        if (!mCancelled) {
+            GTaskClient.getInstance().commitUpdate();
+            refreshLocalSyncId();
+        }
+
+    }
+
+    // 同步文件夹的具体操作方法，处理不同类型文件夹（根文件夹、通话记录文件夹、本地现有文件夹、远程新增文件夹等）的同步
+    private void syncFolder() throws NetworkFailureException {
+        Cursor c = null;
+        String gid;
+        Node node;
+        int syncType;
+
+        if (mCancelled) {
+            return;
+        }
+
+        // 处理根文件夹的同步操作，查询根文件夹并根据情况进行相应同步操作
+        try {
+            c = mContentResolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,
+                    Notes.ID_ROOT_FOLDER), SqlNote.PROJECTION_NOTE, null, null, null);
+            if (c!= null) {
+                c.moveToNext();
+                gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                node = mGTaskHashMap.get(gid);
+                if (node!= null) {
+                    mGTaskHashMap.remove(gid);
+                    mGidToNid.put(gid, (long) Notes.ID_ROOT_FOLDER);
+                    mNidToGid.put((long) Notes.ID_ROOT_FOLDER, gid);
+                    // 对于系统文件夹，仅在必要时更新远程名称
+                    if (!node.getName().equals(
+                            GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT))
+                        doContentSync(Node.SYNC_ACTION_UPDATE_REMOTE, node, c);
+                } else {
+                    doContentSync(Node.SYNC_ACTION_ADD_REMOTE, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query root folder");
+            }
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // 处理通话记录文件夹的同步操作，查询通话记录文件夹并根据情况进行相应同步操作
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE, "(_id=?)",
+                    new String[] {
+                        String.valueOf(Notes.ID_CALL_RECORD_FOLDER)
+                    }, null);
+            if (c!= null) {
+                if (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node!= null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, (long) Notes.ID_CALL_RECORD_FOLDER);
+                        mNidToGid.put((long) Notes.ID_CALL_RECORD        }
+            } else {
+                Log.w(TAG, "failed to query call note folder");
+            }
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // 处理本地现有文件夹的同步操作，查询本地现有文件夹并根据情况确定同步类型，然后执行相应同步操作
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type=? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c!= null) {
+                while (c.moveToNext()) {
+                    gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    node = mGTaskHashMap.get(gid);
+                    if (node!= null) {
+                        mGTaskHashMap.remove(gid);
+                        mGidToNid.put(gid, c.getLong(SqlNote.ID_COLUMN));
+                        mNidToGid.put(c.getLong(SqlNote.ID_COLUMN), gid);
+                        syncType = node.getSyncAction(c);
+                    } else {
+                        if (c.getString(SqlNote.GTASK_ID_COLUMN).trim().length() == 0) {
+                            // 本地添加情况
+                            syncType = Node.SYNC_ACTION_ADD_REMOTE;
+                        } else {
+                            // 远程删除情况
+                            syncType = Node.SYNC_ACTION_DEL_LOCAL;
+                        }
+                    }
+                    doContentSync(syncType, node, c);
+                }
+            } else {
+                Log.w(TAG, "failed to query existing folder");
+            }
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+
+        // 处理远程添加的文件夹，遍历远程任务列表哈希表，进行相应添加本地任务的同步操作
+        Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();
+        while (iter.hasNext()) {
+            Map.Entry<String, TaskList> entry = iter.next();
+            gid = entry.getKey();
+            node = entry.getValue();
+            if (mGTaskHashMap.containsKey(gid)) {
+                mGTaskHashMap.remove(gid);
+                doContentSync(Node.SYNC_ACTION_ADD_LOCAL, node, null);
+            }
+        }
+
+        if (!mCancelled)
+            GTaskClient.getInstance().commitUpdate();
+    }
+
+    // 根据不同的同步类型执行具体的内容同步操作，如添加本地节点、添加远程节点、删除本地节点、删除远程节点等
+    private void doContentSync(int syncType, Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        MetaData meta;
+        switch (syncType) {
+            case Node.SYNC_ACTION_ADD_LOCAL:
+                addLocalNode(node);
+                break;
+            case Node.SYNC_ACTION_ADD_REMOTE:
+                addRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_DEL_LOCAL:
+                meta = mMetaHashMap.get(c.getString(SqlNote.GTASK_ID_COLUMN));
+                if (meta!= null) {
+                    GTaskClient.getInstance().deleteNode(meta);
+                }
+                mLocalDeleteIdMap.add(c.getLong(SqlNote.ID_COLUMN));
+                break;
+            case Node.SYNC_ACTION_DEL_REMOTE:
+                meta = mMetaHashMap.get(node.getGid());
+                if (meta!= null) {
+                    GTaskClient.getInstance().deleteNode(meta);
+                }
+                GTaskClient.getInstance().deleteNode(node);
+                break;
+            case Node.SYNC_ACTION_UPDATE_LOCAL:
+                updateLocalNode(node, c);
+                break;
+            case Node.SYNC_ACTION_UPDATE_REMOTE:
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_UPDATE_CONFLICT:
+                // 合并双方修改可能是个好主意，目前简单使用本地更新
+                updateRemoteNode(node, c);
+                break;
+            case Node.SYNC_ACTION_NONE:
+                break;
+            case Node.SYNC_ACTION_ERROR:
+            default:
+                throw new ActionFailureException("unkown sync action type");
+        }
+    }
+
+    // 添加本地节点的操作方法，根据节点类型（任务列表或普通任务）创建对应的本地记录并进行相关设置和更新
+    private void addLocalNode(Node node) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote;
+        if (node instanceof TaskList) {
+            if (node.getName().equals(
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT)) {
+                sqlNote = new SqlNote(mContext, Notes.ID_ROOT_FOLDER);
+            } else if (node.getName().equals(
+                    GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_CALL_NOTE)) {
+                sqlNote = new SqlNote(mContext, Notes.ID_CALL_RECORD_FOLDER);
+            } else {
+                sqlNote = new SqlNote(mContext);
+                sqlNote.setContent(node.getLocalJSONFromContent());
+                sqlNote.setParentId(Notes.ID_ROOT_FOLDER);
+            }
+        } else {
+            sqlNote = new SqlNote(mContext);
+            JSONObject js = node.getLocalJSONFromContent();
+            try {
+                if (js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+                    JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+                    if (note.has(NoteColumns.ID)) {
+                        long id = note.getLong(NoteColumns.ID);
+                        if (DataUtils.existInNoteDatabase(mContentResolver, id)) {
+                            // 如果ID已存在，需要创建一个新的，移除原来的ID
+                            note.remove(NoteColumns.ID);
+                        }
+                    }
+                }
+
+                if (js.has(GTaskStringUtils.META_HEAD_DATA)) {
+                    JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                    for (int i = 0; i < dataArray.length(); i++) {
+                        JSONObject data = dataArray.getJSONObject(i);
+                        if (data.has(DataColumns.ID)) {
+                            long dataId = data.getLong(DataColumns.ID);
+                            if (DataUtils.existInDataDatabase(mContentResolver, dataId)) {
+                                // 如果数据ID已存在，需要创建一个新的，移除原来的ID
+                                data.remove(DataColumns.ID);
+                            }
+                        }
+                    }
+
+                }
+            } catch (JSONException e) {
+                Log.w(TAG, e.toString());
+                e.printStackTrace();
+            }
+            sqlNote.setContent(js);
+
+            Long parentId = mGidToNid.get(((Task) node).getParent().getGid());
+            if (parentId == null) {
+                Log.e(TAG, "cannot find task's parent id locally");
+                throw new ActionFailureException("cannot add local node");
+            }
+            sqlNote.setParentId(parentId.longValue());
+        }
+
+        // 创建本地节点，提交到本地数据库（不触发本地修改检查）
+        sqlNote.setGtaskId(node.getGid());
+        sqlNote.commit(false);
+
+        // 更新GID和本地记录ID的映射关系
+        mGidToNid.put(node.getGid(), sqlNote.getId());
+        mNidToGid.put(sqlNote.getId(), node.getGid());
+
+        // 更新远程元数据相关信息
+        updateRemoteMeta(node.getGid(), sqlNote);
+    }
+
+    // 更新本地节点的操作方法，更新本地记录的内容、父节点等信息，并更新远程元数据相关信息
+    private void updateLocalNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote;
+        // 根据传入的游标更新本地记录内容
+        sqlNote = new SqlNote(mContext, c);
+        sqlNote.setContent(node.getLocalJSONFromContent());
+
+        Long parentId = (node instanceof Task)? mGidToNid.get(((Task) node).getParent().getGid())
+                : new Long(Notes.ID_ROOT_FOLDER);
+        if (parentId == null) {
+            Log.e(TAG, "cannot find task's parent id locally");
+            throw new ActionFailureException("cannot update local node");
+        }
+        sqlNote.setParentId(parentId.longValue());
+        sqlNote.commit(true);
+
+        // 更新远程元数据相关信息
+        updateRemoteMeta(node.getGid(), sqlNote);
+    }
+
+    // 添加远程节点的操作方法，根据节点类型（任务或任务列表）在远程进行相应创建操作，并更新本地记录相关信息和映射关系
+    private void addRemoteNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);
+        Node n;
+
+        // 根据节点类型进行不同的远程更新操作
+        if (sqlNote.isNoteType()) {
+            Task task = new Task();
+            task.setContentByLocalJSON(sqlNote.getContent());
+
+            String parentGid = mNidToGid.get(sqlNote.getParentId());
+            if (parentGid == null) {
+                Log.e(TAG, "cannot find task's parent tasklist");
+                throw new ActionFailureException("cannot add remote task");
+            }
+            mGTaskListHashMap.get(parentGid).addChildTask(task);
+
+            GTaskClient.getInstance().createTask(task);
+            n = (Node) task;
+
+            // 添加元数据相关更新
+            updateRemoteMeta(task.getGid(), sqlNote);
+        } else {
+            TaskList tasklist = null;
+
+            // 根据不同的本地记录ID确定文件夹名称，查找是否已存在同名文件夹
+            String folderName = GTaskStringUtils.MIUI_FOLDER_PREFFIX;
+            if (sqlNote.getId() == Notes.ID_ROOT_FOLDER)
+                folderName += GTaskStringUtils.FOLDER_DEFAULT;
+            else if (sqlNote.getId() == Notes.ID_CALL_RECORD_FOLDER)
+                folderName += GTaskStringUtils.FOLDER_CALL_NOTE;
+            else
+                folderName += sqlNote.getSnippet();
+
+            Iterator<Map.Entry<String, TaskList>> iter = mGTaskListHashMap.entrySet().iterator();
+            while (iter.hasNext()) {
+                Map.Entry<String, TaskList> entry = iter.next();
+                String gid = entry.getKey();
+                TaskList list = entry.getValue();
+
+                if (list.getName().equals(folderName)) {
+                    tasklist = list;
+                    if (mGTaskHashMap.containsKey(gid)) {
+                        mGTaskHashMap.remove(gid);
+                    }
+                    break;
+                }
+            }
+
+            // 如果没有找到同名文件夹，则创建新的任务列表并上传到远程
+            if (tasklist == null) {
+                tasklist = new TaskList();
+                tasklist.setContentByLocalJSON(sqlNote.getContent());
+                GTaskClient.getInstance().createTaskList(tasklist);
+                mGTaskListHashMap.put(tasklist.getGid(), tasklist);
+            }
+            n = (Node) tasklist;
+        }
+
+        // 更新本地记录的GID等信息，并提交到本地数据库（先提交不触发本地修改检查，再提交触发检查）
+        sqlNote.setGtaskId(n.getGid());
+        sqlNote.commit(false);
+        sqlNote.resetLocalModified();
+        sqlNote.commit(true);
+
+        // 更新GID和本地记录ID的映射关系
+        mGidToNid.put(n.getGid(), sqlNote.getId());
+        mNidToGid.put(sqlNote.getId(), n.getGid());
+    }
+
+    // 更新远程节点的操作方法，更新远程节点内容、移动任务（如果需要）、清除本地修改标记等操作，并更新远程元数据相关信息
+    private void updateRemoteNode(Node node, Cursor c) throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        SqlNote sqlNote = new SqlNote(mContext, c);
+
+        // 更新远程节点内容
+        node.setContentByLocalJSON(sqlNote.getContent());
+        GTaskClient.getInstance().addUpdateNode(node);
+
+        // 更新远程元数据相关信息
+        updateRemoteMeta(node.getGid(), sqlNote);
+
+        // 如果是任务类型，检查是否需要移动任务到不同的任务列表
+        if (sqlNote.isNoteType()) {
+            Task task = (Task) node;
+            TaskList preParentList = task.getParent();
+
+            String curParentGid = mNidToGid.get(sqlNote.getParentId());
+            if (curParentGid == null) {
+                Log.e(TAG, "cannot find task's parent tasklist");
+                throw new ActionFailureException("cannot update remote task");
+            }
+            TaskList curParentList = mGTaskListHashMap.get(curParentGid);
+
+            if (preParentList!= curParentList) {
+                preParentList.removeChildTask(task);
+                curParentList.addChildTask(task);
+                GTaskClient.getInstance().moveTask(task, preParentList, curParentList);
+            }
+        }
+
+        // 清除本地修改标记并提交到本地数据库
+        sqlNote.resetLocalModified();
+        sqlNote.commit(true);
+    }
+
+    // 更新远程元数据的操作方法，根据情况更新已存在的元数据或者创建新的元数据并上传到远程
+    private void updateRemoteMeta(String gid, SqlNote sqlNote) throws NetworkFailureException {
+        if (sqlNote!= null && sqlNote.isNoteType()) {
+            MetaData metaData = mMetaHashMap.get(gid);
+            if (metaData!= null) {
+                metaData.setMeta(gid, sqlNote.getContent());
+                GTaskClient.getInstance().addUpdateNode(metaData);
+            } else {
+                metaData = new MetaData();
+                metaData.setMeta(gid, sqlNote.getContent());
+                mMetaList.addChildTask(metaData);
+                mMetaHashMap.put(gid, metaData);
+                GTaskClient.getInstance().createTask(metaData);
+            }
+        }
+    }
+
+    // 刷新本地同步ID的方法，重新获取最新的Google Task列表信息，然后更新本地记录的同步ID
+    private void refreshLocalSyncId() throws NetworkFailureException {
+        if (mCancelled) {
+            return;
+        }
+
+        // 获取最新的Google Task列表相关数据，清除之前缓存
+        mGTaskHashMap.clear();
+        mGTaskListHashMap.clear();
+        mMetaHashMap.clear();
+        initGTaskList();
+
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, SqlNote.PROJECTION_NOTE,
+                    "(type<>? AND parent_id<>?)", new String[] {
+                            String.valueOf(Notes.TYPE_SYSTEM), String.valueOf(Notes.ID_TRASH_FOLER)
+                    }, NoteColumns.TYPE + " DESC");
+            if (c!= null) {
+                while (c.moveToNext()) {
+                    String gid = c.getString(SqlNote.GTASK_ID_COLUMN);
+                    Node node = mGTaskHashMap.get(gid);
+                    if (node!= null) {
+                        mGTaskHashMap.remove(gid);
+                        ContentValues values = new ContentValues();
+                        values.put(NoteColumns.SYNC_ID, node.getLastModified());
+                        mContentResolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI,
+                                c.getLong(SqlNote.ID_COLUMN)), values, null, null);
+                    } else {
+                        Log.e(TAG, "something is missed");
+                        throw new ActionFailureException(
+                                "some local items don't have gid after sync");
+                    }
+                }
+            } else {
+                Log.w(TAG, "failed to query local note to refresh sync id");
+            }
+        } finally {
+            if (c!= null) {
+                c.close();
+                c = null;
+            }
+        }
+    }
+
+    // 获取同步账户名称的方法
+    public String getSyncAccount() {
+        return GTaskClient.getInstance().getSyncAccount().name;
+    }
+
+    // 取消同步的方法，设置同步已取消的标记
+    public void cancelSync() {
+        mCancelled = true;
+    }
+}

src/GTaskSyncService.java

@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.remote;
+
+import android.app.Activity;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.IBinder;
+
+/**
+ * GTaskSyncService 是一个后台服务，用于管理Google任务（GTask）的同步操作。
+ * 它提供启动和取消同步的方法，并在同步过程中广播进度更新。
+ */
+public class GTaskSyncService extends Service {
+
+    /**
+     * 表示同步动作类型的字符串常量名。
+     */
+    public final static String ACTION_STRING_NAME = "sync_action_type";
+
+    /**
+     * 同步开始的动作代码。
+     */
+    public final static int ACTION_START_SYNC = 0;
+
+    /**
+     * 取消同步的动作代码。
+     */
+    public final static int ACTION_CANCEL_SYNC = 1;
+
+    /**
+     * 无效或未定义的动作代码。
+     */
+    public final static int ACTION_INVALID = 2;
+
+    /**
+     * 广播名称，用于发送同步状态和服务消息。
+     */
+    public final static String GTASK_SERVICE_BROADCAST_NAME = "net.micode.notes.gtask.remote.gtask_sync_service";
+
+    /**
+     * 广播中表示是否正在进行同步的键名。
+     */
+    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";
+
+    /**
+     * 广播中表示同步进度信息的键名。
+     */
+    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";
+
+    /**
+     * 当前执行的同步任务实例。
+     */
+    private static GTaskASyncTask mSyncTask = null;
+
+    /**
+     * 当前同步任务的进度信息。
+     */
+    private static String mSyncProgress = "";
+
+    /**
+     * 开始同步操作。如果当前没有正在运行的同步任务，则创建并启动一个新的同步任务。
+     */
+    private void startSync() {
+        if (mSyncTask == null) {
+            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
+                @Override
+                public void onComplete() {
+                    mSyncTask = null;
+                    sendBroadcast("");
+                    stopSelf();
+                }
+            });
+            sendBroadcast("");
+            mSyncTask.execute();
+        }
+    }
+
+    /**
+     * 取消正在进行的同步操作。
+     */
+    private void cancelSync() {
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+
+    /**
+     * 当服务被创建时调用。
+     */
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        mSyncTask = null;
+    }
+
+    /**
+     * 当服务接收到启动命令时调用。
+     */
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        Bundle bundle = intent.getExtras();
+        if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) {
+            switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) {
+                case ACTION_START_SYNC:
+                    startSync();
+                    break;
+                case ACTION_CANCEL_SYNC:
+                    cancelSync();
+                    break;
+                default:
+                    // 忽略未知动作
+                    break;
+            }
+            return START_STICKY; // 如果进程被杀死，尝试重启服务
+        }
+        return super.onStartCommand(intent, flags, startId);
+    }
+
+    /**
+     * 当系统内存不足时调用，尝试释放资源。
+     */
+    @Override
+    public void onLowMemory() {
+        super.onLowMemory();
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+
+    /**
+     * 返回绑定到此服务的IBinder对象，本服务不支持绑定，所以返回null。
+     */
+    @Override
+    public IBinder onBind(Intent intent) {
+        return null;
+    }
+
+    /**
+     * 发送广播以通知其他组件当前同步的状态和进度。
+     */
+    public void sendBroadcast(String msg) {
+        mSyncProgress = msg;
+        Intent intent = new Intent(GTASK_SERVICE_BROADCAST_NAME);
+        intent.putExtra(GTASK_SERVICE_BROADCAST_IS_SYNCING, mSyncTask != null);
+        intent.putExtra(GTASK_SERVICE_BROADCAST_PROGRESS_MSG, msg);
+        sendBroadcast(intent);
+    }
+
+    /**
+     * 静态方法，从Activity启动同步服务。
+     */
+    public static void startSync(Activity activity) {
+        GTaskManager.getInstance().setActivityContext(activity);
+        Intent intent = new Intent(activity, GTaskSyncService.class);
+        intent.putExtra(ACTION_STRING_NAME, ACTION_START_SYNC);
+        activity.startService(intent);
+    }
+
+    /**
+     * 静态方法，通过上下文取消同步操作。
+     */
+    public static void cancelSync(Context context) {
+        Intent intent = new Intent(context, GTaskSyncService.class);
+        intent.putExtra(ACTION_STRING_NAME, ACTION_CANCEL_SYNC);
+        context.startService(intent);
+    }
+
+    /**
+     * 检查是否有同步任务正在进行。
+     */
+    public static boolean isSyncing() {
+        return mSyncTask != null;
+    }
+
+    /**
+     * 获取当前同步任务的进度信息。
+     */
+    public static String getProgressString() {
+        return mSyncProgress;
+    }
+}

src/NetworkFailureException.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.gtask.exception;
+
+/**
+ * NetworkFailureException 类是用于表示网络操作失败时抛出的异常。
+ * 它继承自 Exception，因此它是一个检查型异常（checked exception），
+ * 这意味着在方法签名中需要声明此异常可能会被抛出，以确保调用者处理或重新抛出该异常。
+ */
+public class NetworkFailureException extends Exception {
+
+    // 序列化版本唯一标识符，用于确保类的不同版本之间的兼容性。
+    private static final long serialVersionUID = 2107610287180234136L;
+
+    /**
+     * 构造一个新的 NetworkFailureException，不带任何详细信息消息或原因。
+     */
+    public NetworkFailureException() {
+        super();
+    }
+
+    /**
+     * 使用指定的详细信息消息构造一个新的 NetworkFailureException。
+     * @param message 提供更多关于异常的信息的消息字符串。
+     */
+    public NetworkFailureException(String message) {
+        super(message);
+    }
+
+    /**
+     * 使用指定的详细信息消息和原因构造一个新的 NetworkFailureException。
+     * @param message 提供更多关于异常的信息的消息字符串。
+     * @param cause 导致当前异常的底层原因。
+     */
+    public NetworkFailureException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}