如何在停止服務後從傳感器註銷偵聽器？

Question

我正在創建一個應用程序，在按下「開始」按鈕時啓動服務，並在按下「停止」按鈕時停止它。在服務中，我註冊了傳感器ACCELEROMETER的監聽器，以便獲取x，y，z軸的加速度計值。但是，當我停止應用程序並從傳感器註銷監聽器時，即使這樣我仍然可以獲得加速度計值。

下面的代碼：

// Service 
public class Accel extends Service 
{ 
    private static Context CONTEXT; 
    private static Sensor sensor; 
    private static SensorManager sensorManager; 
    private static boolean running = false; 

    @Override 
    public void onCreate() 
    { 
    } 

    // code to execute when the service is shutting down 
    @Override 
    public void onDestroy() 
    { 
     if (isListening()) 
      stopListening(); 
    } 

    // code to execute when the service is starting up 
    @Override 
    public void onStart(Intent intent, int startid) 
    { 
     CONTEXT = this; 
     startListening(this); 
    } 

    public static Context getContext() 
    { 
     return CONTEXT; 
    } 

    // Returns true if the manager is listening to orientation changes 
    public static boolean isListening() 
    { 
     return running; 
    } 

    //Unregisters listeners 
    public static void stopListening() 
    { 
     running = false; 
     sensorManager.unregisterListener(sensorEventListener, sensor); 
    } 

    /** 
    * Registers a listener and start listening 
    * @param accelerometerListener 
    *    callback for accelerometer events 
    */ 
    public static void startListening(AccelerometerListener accelerometerListener) 
    { 
     sensorManager = (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE); 
     List<Sensor> sensors = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER); 
     if (sensors.size() > 0) 
     { 
      sensor = sensors.get(0); 
      running = sensorManager.registerListener(sensorEventListener, sensor, SensorManager.SENSOR_DELAY_GAME); 
      listener = accelerometerListener; 
     } 
    } 

    /** 
    * The listener that listen to events from the accelerometer listener 
    */ 
    private static SensorEventListener sensorEventListener = 
    new SensorEventListener() 
    { 
    public void onAccuracyChanged(Sensor sensor, int accuracy) {} 
    public void onSensorChanged(SensorEvent event) 
    { 
       // the code to perform on sensor change 
    } 
}; 

}

任何人都可以請幫我？

Answer 1

onDestroy()可能不會被您的應用程序中的操作系統直接調用。將您的stopListening()呼叫撥入您的onResume()功能中的onPause()和startListening()。通過這種方式，您可以確保應用程序註冊並使用傳感器取消註冊。