アンドロイドでバックグラウンドでフォアグラウンドサービスを実行する方法

Question

フォアグラウンドでのみ実行されるコードは、画面のロックとバックグラウンドの間にアプリを振ることでオン/オフを切り替えることができますフォアグラウンドサービスはバックグラウンドで継続できます。

MainActivty.java

public class Torchclass extends Activity { 

    // The following are used for the shake detection 
private SensorManager mSensorManager; 
private Sensor mAccelerometer; 
private ShakeDetector mShakeDetector; 
public static Camera cam = null; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.torchlayout); 

    Intent intent = new Intent(Torchclass.this, ShakeService.class); 
    startService(intent); 

    // ShakeDetector initialization 
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); 
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); 
    mShakeDetector = new ShakeDetector(); 
    mShakeDetector.setOnShakeListener(new ShakeDetector.OnShakeListener() { 

     @Override 
     public void onShake(int count) { 
      try { 
       if (getPackageManager().hasSystemFeature(
         PackageManager.FEATURE_CAMERA_FLASH)) { 
        cam = Camera.open(); 
        Parameters p = cam.getParameters(); 
        p.setFlashMode(Parameters.FLASH_MODE_TORCH); 
        cam.setParameters(p); 
        cam.startPreview(); 
       } 
      } catch (Exception e) { 

       e.printStackTrace(); 
       Toast.makeText(getBaseContext(), "Exception flashLightOn()", 
         Toast.LENGTH_SHORT).show(); 

       if (getPackageManager().hasSystemFeature(
         PackageManager.FEATURE_CAMERA_FLASH)) { 
        cam.stopPreview(); 
        cam.release(); 
        cam = null; 
       } 
      } 

     } 
    }); 
} 

@Override 
public void onResume() { 
    super.onResume(); 
    // Add the following line to register the Session Manager Listener onResume 
    mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI); 
} 

@Override 
public void onPause() { 
    // Add the following line to unregister the Sensor Manager onPause 
     mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI); 

    super.onPause(); 
} 
} 

ShakeDetector.java

public class ShakeDetector implements SensorEventListener { 

/* 
* The gForce that is necessary to register as shake. 
* Must be greater than 1G (one earth gravity unit). 
* You can install "G-Force", by Blake La Pierre 
* from the Google Play Store and run it to see how 
* many G's it takes to register a shake 
*/ 
private static final float SHAKE_THRESHOLD_GRAVITY = 2.7F; 
private static final int SHAKE_SLOP_TIME_MS = 500; 
private static final int SHAKE_COUNT_RESET_TIME_MS = 3000; 

private OnShakeListener mListener; 
private long mShakeTimestamp; 
private int mShakeCount; 

public void setOnShakeListener(OnShakeListener listener) { 
    this.mListener = listener; 
} 

public interface OnShakeListener { 
    public void onShake(int count); 
} 

@Override 
public void onAccuracyChanged(Sensor sensor, int accuracy) { 
    // ignore 
} 

@Override 
public void onSensorChanged(SensorEvent event) { 

    if (mListener != null) { 
     float x = event.values[0]; 
     float y = event.values[1]; 
     float z = event.values[2]; 

     float gX = x/SensorManager.GRAVITY_EARTH; 
     float gY = y/SensorManager.GRAVITY_EARTH; 
     float gZ = z/SensorManager.GRAVITY_EARTH; 

     // gForce will be close to 1 when there is no movement. 
     Float f = new Float(gX * gX + gY * gY + gZ * gZ); 
     Double d = Math.sqrt(f.doubleValue()); 
     float gForce = d.floatValue(); 

     if (gForce > SHAKE_THRESHOLD_GRAVITY) { 
      final long now = System.currentTimeMillis(); 
      // ignore shake events too close to each other (500ms) 
      if (mShakeTimestamp + SHAKE_SLOP_TIME_MS > now) { 
       return; 
      } 

      // reset the shake count after 3 seconds of no shakes 
      if (mShakeTimestamp + SHAKE_COUNT_RESET_TIME_MS < now) { 
       mShakeCount = 0; 
      } 

      mShakeTimestamp = now; 
      mShakeCount++; 

      mListener.onShake(mShakeCount); 
     } 
    } 
} 
} 

ShakeService.java

public class ShakeService extends Service { 

private SensorManager mSensorManager; 
private Sensor mAccelerometer; 
private ShakeDetector mShakeDetector; 

public ShakeService() { 
} 

@Override 
public IBinder onBind(Intent intent) { 
    // TODO: Return the communication channel to the service. 
    throw new UnsupportedOperationException("Not yet implemented"); 
} 

@Override 
public void onCreate() { 
    super.onCreate(); 
    // ShakeDetector initialization 
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); 
    mAccelerometer = mSensorManager 
      .getDefaultSensor(Sensor.TYPE_ACCELEROMETER); 
    mShakeDetector = new ShakeDetector(); 
    mShakeDetector.setOnShakeListener(new ShakeDetector.OnShakeListener() { 

     @Override 
     public void onShake(int count) { 

      Intent i = getApplicationContext().getPackageManager().getLaunchIntentForPackage("com.facebook.katana"); 
      getApplicationContext().startActivity(i); 

     } 
    }); 
    mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI); 
} 

@Override 
public void onDestroy() { 
    mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI); 

    super.onDestroy(); 
} 
} 

Answer 1

あなたはサービスでメソッドをオーバーライドする必要がありonStartCommand：

public int onStartCommand(Intent intent, int flags, int startId) { 
{ 
return START_STICKY 
}