protected static final String TAG = "WatchDogService";
private AppLockDao dao;
private List<String> lockApps;
private ActivityManager am;
private Intent lockappintent;
@Override
public IBinder onBind(Intent intent) {
    return null;
}
/**
* 服務(wù)第一次被調(diào)用的時候調(diào)用 的方法
*/
@Override
public void onCreate() {
    super.onCreate();
    dao = new AppLockDao(this);
    //得到所用的要鎖定的應(yīng)用程序
    lockApps = dao.getAllPackName();
    am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
    lockappintent = new Intent(this,LockScreenActivity.class);
    lockappintent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    new Thread(){
      public void run() {
        while(true){
          try {
            //得到當(dāng)前正在運(yùn)行應(yīng)用程序的報名
            //返回系統(tǒng)里的任務(wù)棧的信息，taskInfos只有一個元素，對應(yīng)當(dāng)前正在運(yùn)行的應(yīng)用程序
            List<RunningTaskInfo> taskInfos = am.getRunningTasks(1);
            RunningTaskInfo currentTask = taskInfos.get(0);
            //獲取當(dāng)前用戶可見的Activity所在的程序的包名
            String packName = currentTask.topActivity.getPackageName();
            Log.i(TAG, "當(dāng)前運(yùn)行的程序包名："+packName);
            if(lockApps.contains(packName)){//鎖定
              lockappintent.putExtra("packname", packName);
              startActivity(lockappintent);
            }else{//放行
            }
            sleep(200);
          } catch (Exception e) {
            e.printStackTrace();
          }
        }
      };
    }.start();
}