diff --git a/GTaskSyncService.java.txt b/GTaskSyncService.java.txt
new file mode 100644
index 0000000..d4f105c
--- /dev/null
+++ b/GTaskSyncService.java.txt
@@ -0,0 +1,114 @@
+package net.micode.notes.gtask.remote;
+
+// Service是在一段不定的时间运行在后台，不和用户交互的应用组件
+
+public class GTaskSyncService extends Service {
+    public final static String ACTION_STRING_NAME = "sync_action_type";
+ 
+    public final static int ACTION_START_SYNC = 0;
+ 
+    public final static int ACTION_CANCEL_SYNC = 1;
+ 
+    public final static int ACTION_INVALID = 2;
+ 
+    public final static String GTASK_SERVICE_BROADCAST_NAME = "net.micode.notes.gtask.remote.gtask_sync_service";
+ 
+    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";
+ 
+    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";
+ 
+    private static GTaskASyncTask mSyncTask = null;
+ 
+    private static String mSyncProgress = "";
+    
+    //开始一个同步的工作
+    private void startSync() {
+        if (mSyncTask == null) {
+            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
+                public void onComplete() {
+                    mSyncTask = null;
+                    sendBroadcast("");
+                    stopSelf();  
+                }
+            });
+            sendBroadcast("");
+            mSyncTask.execute(); //这个函数让任务是以单线程队列方式或线程池队列方式运行
+        }
+    }
+    
+    //取消同步的方法
+    private void cancelSync() {
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+ 
+    @Override
+    public void onCreate() {  //初始化一个service
+        mSyncTask = null;
+    }
+ 
+
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {////service生命周期的组成部分，相当于重启service（比如在被暂停之后），而不是创建一个新的
+        Bundle bundle = intent.getExtras();
+        if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) {
+            switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) {
+            //两种情况，开始同步或者取消同步
+                case ACTION_START_SYNC:
+                    startSync();
+                    break;
+                case ACTION_CANCEL_SYNC:
+                    cancelSync();
+                    break;
+                default:
+                    break;
+            }
+            return START_STICKY; //等待新的intent来是这个service继续运行
+        }
+        return super.onStartCommand(intent, flags, startId);
+    }
+ 
+    @Override
+    public void onLowMemory() { //在没有内存的情况下如果存在service则结束掉这的service
+
+        if (mSyncTask != null) {
+            mSyncTask.cancelSync();
+        }
+    }
+ 
+    public IBinder onBind(Intent intent) {  
+        return null;
+    }
+ 
+    public void sendBroadcast(String msg) {  //发送同步的相关通知
+        mSyncProgress = msg;
+        Intent intent = new Intent(GTASK_SERVICE_BROADCAST_NAME);  //创建一个新的Intent
+        intent.putExtra(GTASK_SERVICE_BROADCAST_IS_SYNCING, mSyncTask != null); //附加INTENT中的相应参数的值
+        intent.putExtra(GTASK_SERVICE_BROADCAST_PROGRESS_MSG, msg);
+        sendBroadcast(intent);   //发送这个通知
+    }
+ 
+    public static void startSync(Activity activity) {//执行一个service，service的内容里的同步动作就是开始同步
+        GTaskManager.getInstance().setActivityContext(activity);
+        Intent intent = new Intent(activity, GTaskSyncService.class);
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_START_SYNC);
+        activity.startService(intent);
+    }
+ 
+    public static void cancelSync(Context context) {//执行一个service，service的内容里的同步动作就是取消同步
+        Intent intent = new Intent(context, GTaskSyncService.class);
+        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_CANCEL_SYNC);
+        context.startService(intent);
+    }
+ 
+    public static boolean isSyncing() { //判读是否在进行同步
+        return mSyncTask != null;
+    }
+ 
+    public static String getProgressString() {  // 获取当前进度的信息
+
+        return mSyncProgress;
+    }
+}
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