如何停止系列postDelayed處理程序

Question

我有一系列postDelayed處理程序。我無法設置一個停止處理程序的方法，當用戶在任何他想要的時間點擊停止按鈕時。

我會感謝任何人能夠提供幫助。 感謝

while (!lessonIsRunning) { 
     Handler handler0 = new Handler(); 
     handler0.postDelayed(new Runnable() { 
      @Override 
      public void run() { 
       plate1.setVisibility(ImageView.VISIBLE); 
       plate2.setVisibility(ImageView.VISIBLE); 
       plate3.setVisibility(ImageView.VISIBLE); 
      } 
     }, 6000); 

     Handler handler1 = new Handler(); 
     handler1.postDelayed(new Runnable() { 
      @Override 
      public void run() { 
       apples1.setVisibility(ImageView.VISIBLE); 
      } 
     }, 9000); 

     Handler handler2 = new Handler(); 
     handler2.postDelayed(new Runnable() { 
      @Override 
      public void run() { 
       plus1.setVisibility(TextView.VISIBLE); 
      } 
     }, 9250); 
} 
public void stopLesson(View V){ 

} 

Answer 1

而不是你必須用一個名稱來定義它的一個匿名的方式編寫可運行的任務，這樣以後你將有一個鏈接刪除：

//there is no need for multiple handlers 
//handler must be declared outside all functions, in order for you to use it everywhere. 

Handler handler = new Handler(); 
Runnable myFirstTask = new Runnable(){ 
     @Override 
       public void run() { 
        plate1.setVisibility(ImageView.VISIBLE); 
        plate2.setVisibility(ImageView.VISIBLE); 
        plate3.setVisibility(ImageView.VISIBLE); 
       } }; 

    Runnable mySecondTask = new Runnable(){ 
     @Override 
       public void run() { 
        plus1.setVisibility(TextView.VISIBLE); 
       } 

    }; 

    Runnable myThirdTask = new Runnable(){ 
     @Override 
       public void run() { 
        apples1.setVisibility(ImageView.VISIBLE); 
       } } 

    //you can put different tasks on the same handler object 

    while (!lessonIsRunning) { 
      handler.postDelayed(myFirstTask,6000); 
      handler.postDelayed(mySecondTask,9250); 
      handler.postDelayed(myThirdTask,9000); 
} 
public void stopLesson(View V){ 
    //notice that you don't need these, because the handlers are not recursive 
    //you don't have lines "handler.postDelayed(sameTask,someTime);" 
    //in your run Method of the runnable 
if(handler!=null){ 
    handler.removeCallbacks(myFirstTask); 
    handler.removeCallbacks(mySecondTask); 
    handler.removeCallbacks(myThirdTask); 
    //if this method is inside onPause or onDestroy add this line as well: 
    handler=null; 

} 
} 

Answer 2

你可以給

handler0.removeCallbacksAndMessages(null); 
handler1.removeCallbacksAndMessages(null); 
handler2.removeCallbacksAndMessages(null); 

一試。該文檔說，當您提交空令牌時，所有回調和消息都將被刪除。