如何停止和启动异步任务。（Android）

我有启动和停止按钮，还有文本视图 我要单击按钮开始文本视图倒计时100->0。 当我单击按钮停止倒计时停止，然后我单击按钮重新开始倒计时继续。 对不起，我的英语不好

类似的事

private Handler h = null;
final int delay = 2500; //millisecond
private Runnable myRunnable = new Runnable(){
    public void run(){
         runOnUiThread(new Runnable() {
            //Stuff here
         }
        }
    };

//To stop Handler when you leave your activity
@Override
public void onStop() {
    super.onStop();
    if (h != null && myRunnable != null) h.removeCallbacks(myRunnable);
    Log.d(TAG, "Stop Handler");
}

//Call this when you want to start your work
public void StartHandler(){
    h = new Handler();
    h.postDelayed(myRunnable, delay);
    Log.d(TAG, "Start Handler");
}