private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
                @Override
               public void onReceive(Context context, Intent intent) {
                       unregisterReceiver(this); // 這句話必須要寫要不會報錯，不寫雖然能關閉，會報一堆錯
                       ((Activity) context).finish();
                    }
            };

                @Override
       public void onResume() {
               super.onResume();

               // 在當前的activity中註冊廣播
                    IntentFilter filter = new IntentFilter();
               filter.addAction("liu");
               registerReceiver(this.broadcastReceiver, filter); // 註冊
            }

    public void close() {
                Intent intent = new Intent();
                intent.setAction("liu"); // 說明動作
                sendBroadcast(intent);// 該函式用於傳送廣播
                finish();
    }