如何让方法每隔一次什么都不做？

Question

我正在尝试制作一个应用程序，它只在接近传感器被覆盖时播放声音，但是当传感器未覆盖时，它会再次播放声音。

如何让它只在被覆盖时播放声音，而在未覆盖时不播放任何声音？

public class MainActivity extends ActionBarActivity {


SensorManager sm;
Sensor ProximitySensor;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment())
                .commit();
    }

    sm = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
    ProximitySensor = sm.getDefaultSensor(Sensor.TYPE_PROXIMITY);
    sm.registerListener(proximitySensorEventListener,
            ProximitySensor,
            SensorManager.SENSOR_DELAY_FASTEST);

}



SensorEventListener proximitySensorEventListener = new SensorEventListener() {
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_PROXIMITY) {
                call();
        }

    }
};

    private void call() {
        ImageView im = (ImageView) findViewById(R.id.nfcoff);
        ImageView imm = (ImageView) findViewById(R.id.buz);

        if (im.getVisibility() == View.INVISIBLE && imm.getVisibility() == View.VISIBLE) {
            mp = MediaPlayer.create(this, R.raw.ovnoise);
            mp.start();
            mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                @Override
                public void onCompletion(MediaPlayer mp) {
                    mp.release();
                }
            });


        } else
            if (im.getVisibility() == View.INVISIBLE && imm.getVisibility() == View.INVISIBLE) {
                mp = MediaPlayer.create(this, R.raw.ovbus);
                mp.start();
                mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mp) {
                        mp.release();
                    }
                });
            }
        }

Answer 1

我添加了一个int count来计算该方法被调用的次数，并添加了一个if语句，声明该方法只有在int为奇数时才能被调用，这使得该方法每隔一次被调用都是无效的。

static int count = 0;

count++;

if (count % 2 != 0) {}