爲什麼if語句在仿真器上工作，但不在實際設備上工作

Question

我想要有一個定時器對話框，它將從0開始，每5秒發出一個聲音。它適用於Nexus S API 22的仿真器，但不適用於我的HTC One M8 API 21手機。記錄日誌消息並在模擬器上聽到聲音，但在我的實際電話上都沒有發生，所以我認爲這不是一個合理的問題。

private Runnable updateTimerThread = new Runnable() { 

    public void run() { 
     timeInMilliseconds = SystemClock.uptimeMillis() - startTime; 

     updatedTime = timeSwapBuff + timeInMilliseconds; 

     int secs = (int) (updatedTime/1000); 
     int mins = secs/60; 
     secs = secs % 60; 
     int milliseconds = (int) (updatedTime % 1000); 

     if(secs > 0 && ((secs%5) == 0) && milliseconds == 0){ 
      Log.d("BEEP", "beep"); 
      tg.startTone(ToneGenerator.TONE_PROP_BEEP); 
     } 

     timerValue.setText("" + mins + ":" 
       + String.format("%02d", secs) + ":" 
       + String.format("%03d", milliseconds)); 
     customHandler.postDelayed(this, 0); 
    } 
}; 

這裏也是用於參考的onCreate和變量名。

public class TimerDialogFragment extends DialogFragment implements DialogInterface.OnClickListener{  

private TextView timerValue; 

private long startTime = 0L; 

private Handler customHandler = new Handler(); 

long timeInMilliseconds = 0L; 
long timeSwapBuff = 0L; 
long updatedTime = 0L; 

ToneGenerator tg; 

@Override 
public Dialog onCreateDialog(Bundle savedInstanceState) { 
    super.onCreateDialog(savedInstanceState); 
    View v = getActivity().getLayoutInflater().inflate(R.layout.dialog_timer,null); 

    tg = new ToneGenerator(AudioManager.STREAM_NOTIFICATION, 100); 

    timerValue = (TextView) v.findViewById(R.id.timerText); 
    startTime = SystemClock.uptimeMillis(); 
    customHandler.postDelayed(updateTimerThread, 0); 



    return new AlertDialog.Builder(getActivity()) 
      .setView(v) 
      .setMessage("") 
      .setCancelable(true) 
      .setNegativeButton("Continue with instructions",this) 
      .create(); 
} 

.... 

} 

Answer 1

在這個片斷：

if(secs > 0 && ((secs%5) == 0) && milliseconds == 0){ 
     Log.d("BEEP", "beep"); 
     tg.startTone(ToneGenerator.TONE_PROP_BEEP); 
    } 

你在milliseconds計數是爲了爲0的蜂鳴聲。這不是一個可靠的假設 - 這是一種非常糟糕的編碼習慣。如果你想發出蜂鳴聲，每5秒，改變你的Runnable這樣：

private Runnable updateTimerThread = new Runnable() { 
    public void run() { 
    timeInMilliseconds = SystemClock.uptimeMillis() - startTime; 

    updatedTime = timeSwapBuff + timeInMilliseconds; 

    int secs = (int) (updatedTime/1000); 
    int mins = secs/60; 
    secs = secs % 60; 
    int milliseconds = (int) (updatedTime % 1000); 

    // if(secs > 0 && ((secs%5) == 0) && milliseconds == 0){ // <<<<<<<<< 
    Log.d("BEEP", "beep"); 
    tg.startTone(ToneGenerator.TONE_PROP_BEEP); 
    // } // <<<<<<<<< 

    timerValue.setText("" + mins + ":" 
      + String.format("%02d", secs) + ":" 
      + String.format("%03d", milliseconds)); 
    customHandler.postDelayed(this, 5000); // <<<<<<<<< 
    } 
};