Volume control pressing in Android game

Question

I'm developing a simple Android game that plays sound in background by service. When game starts, the sound is playing good. But when pressing volume up key or down button, the app exits immediately.

public class PlayAudio extends Service{
    private static final String LOGCAT = null;
    MediaPlayer objPlayer;

    public void onCreate(){
        super.onCreate();
        Log.d(LOGCAT, "Service Started!");
        objPlayer = MediaPlayer.create(this,R.raw.relax);
    }

    public int onStartCommand(Intent intent, int flags, int startId){
        objPlayer.start();
        Log.d(LOGCAT, "Media Player started!");
        if(objPlayer.isLooping() != true){
            Log.d(LOGCAT, "Problem in Playing Audio");
        }
        return 1;
    }

    public void onStop(){
        objPlayer.stop();
        objPlayer.release();
    }

    public void onPause(){
        objPlayer.stop();
        objPlayer.release();
    }

    public void onDestroy(){
        objPlayer.stop();
        objPlayer.release();
    }

    @Override
    public IBinder onBind(Intent objIndent) {
        return null;
    }
}

this code to start playing sound

public void playAudio() {
    Intent objIntent = new Intent(this, PlayAudio.class);
    startService(objIntent);
}

Answer 1

Problem solved. I just missed the condition:

if (keyCode == KeyEvent.KEYCODE_BACK){}