bar.setProgress（0）不起作用

Question

以下代碼來自Beginning Android 3，Chapter 20.當手機旋轉時，將創建一個新的活動並調用onStart（），所以bar.setProgress（） 0）被調用。但是，我沒有看到酒吧的進展回到了開始。爲什麼不？

public class HandlerDemo extends Activity { 
    ProgressBar bar; 
    Handler handler=new Handler() { 
     @Override 
     public void handleMessage(Message msg) { 
      bar.incrementProgressBy(5); 
     } 
    }; 

    AtomicBoolean isRunning=new AtomicBoolean(false); 

    @Override 
    public void onCreate(Bundle icicle) { 
     super.onCreate(icicle); 
     setContentView(R.layout.main); 
     bar=(ProgressBar)findViewById(R.id.progress); 
    } 
    public void onStart() { 
     super.onStart(); 
     bar.setProgress(0); 
     Thread background=new Thread(new Runnable() { 
      public void run() { 
       try { 
        for (int i=0;i<20 && isRunning.get();i++) { 
         Thread.sleep(1000); 
         handler.sendMessage(handler.obtainMessage()); 
        } 
       } catch (Throwable t) { 
       // just end the background thread 
       } 
      } 
     }); 
     isRunning.set(true); 
     background.start(); 
    } 

    public void onStop() { 
     super.onStop(); 
     isRunning.set(false); 
    } 
} 

Answer 1

嘗試使用此代碼

@Override 
    protected void onPause() { 
      super.onPause(); 
      isRunning.set(false); 
      bar.setProgress(0); 
    }