安卓定時器在服務 - 如何停止和啓動

我已閱讀了很多帖子，但無法找到我的具體問題的答案。安卓定時器在服務 - 如何停止和啓動

下面的服務運作良好。我可以開始它。開始。我可以阻止它。它停下來。我可以重新啓動一個新的時間間隔。這也適用。當我停止時，它不會停止。在onDestroy中，這是timer = null的情況。如果我將timer.cancel插入到timer = null情況下的onDestroy中，那麼我會在執行空指針時發生崩潰。然而，它仍然在運行，如日誌輸出所示！

這裏是日誌輸出，如果有幫助的（最後的「noOutRows」後，它只是不斷運行）

E/ timer: startservice 
E/ timer: timeInterval 1000 
E/ timer: isNotNull 
E/ timer: no noOutRows 1503945704743 
E/ timer: no noOutRows 1503945705712 
E/ timer: no noOutRows 1503945706714 
E/ timer: no noOutRows 1503945707713 
E/ timer: no noOutRows 1503945708712 
E/ timer: stopservice 
E/ timer: stop - isNotNull 
E/ timer: startservice 
E/ timer: timeInterval 5000 
E/ timer: isNull 
E/ timer: no noOutRows 1503945744406 
E/ timer: no noOutRows 1503945749407 
E/ timer: no noOutRows 1503945754407 
E/ timer: stopservice 
E/ timer: stop - isNull 
E/ timer: no noOutRows 1503945759407 
E/ timer: no noOutRows 1503945764407 
E/ timer: no noOutRows 1503945769773

這裏是我的代碼

public class LocalService extends Service 
{ 
    public Integer timeInterval = 1000; 
    private static Timer timer = new Timer(); 
    public IBinder onBind(Intent arg0) 
    { 
     return null; 
    } 

    @Override 
    public void onCreate() 
    { 
     super.onCreate(); 
    } 
    @Override 
    public int onStartCommand(Intent intent, int flags, int startId) { 
     Log.e(" timer"," startservice"); 
     int newTimeInterval = intent.getIntExtra("time_interval", -99); 
      timeInterval = newTimeInterval; 
      Log.e(" timer ", " timeInterval " + timeInterval); 
      if (timer == null){ 
       Log.e(" timer"," isNull"); 
       Timer timer = new Timer(); 
       timer.scheduleAtFixedRate(new mainTask(), 0, timeInterval); 
      } else { 
       Log.e(" timer"," isNotNull"); 
       timer.scheduleAtFixedRate(new mainTask(), 0, timeInterval); 
      } 
     return START_STICKY; 
    } 
    private class mainTask extends TimerTask 
    { 
     public void run() 
     { 
      logHandler.sendEmptyMessage(0); 
     } 
    } 
    public void onDestroy() 
    { 
     Log.e(" timer"," stopservice"); 
     if (timer != null) { 
      Log.e(" timer"," stop - isNotNull"); 
      timer.cancel(); 
      timer = null; 
     } else { 
      Log.e(" timer"," stop - isNull"); 
     } 
     super.onDestroy(); 
    } 
    private final Handler logHandler = new Handler() 
    { 
     @Override 
     public void handleMessage(Message msg) 
     { 
      int maxRows = MainActivity.Cache.alls.size()-1; 
      if (maxRows > 0) { 
       Log.e(" timer ", " outRows " + maxRows + " " + MainActivity.Cache.alls.get(maxRows).toString()); 
      } else { 
       Log.e(" timer ", " no noOutRows " + MainActivity.utcNow().getTime()); 
      } 
     } 
    }; 
}

來源

2017-08-28 Frank Zappa

這難道不正常嗎？ https://stackoverflow.com/q/9093271/1531971 – jdv

謝謝。好問題。我對START_STICKY不是很熟悉。不過，我會嘗試下面的Runnable方法。 –

出於某種原因，我不不記得所有人都同意在Android中不使用定時器，他們選擇了Runnable/Handler組合。它是這樣的

private static final int delay = 1000; 
private final Handler handler = new Handler(); 

Runnable runnable = new Runnable() { 
    @Override 
    public void run() { 
     yourAdvancedScheduledLogic();//pre or post as you wish 
     if(!yourExitCondition()) { 
      handler.postDelayed(this, delay); 
     } 
    } 
};

和

runnable.run();//stars the timer

來源

2017-08-28 19:28:23 Nick

謝謝。我創建了一個類，並將上面的代碼放在其中。現在我只需要處理啓動/停止並傳遞延遲值。 –

安卓定時器在服務 - 如何停止和啓動

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