Android Gyroscope Hatası

public class MainActivity extends AppCompatActivity { ImageView img = null; private SensorManager mSensorManager; private Sensor mSensor; float buttonX; float buttonY; float viewWidth; float viewHeight; EditText webin; TextView TextX; TextView TextY; TextView TextZ; float x; float y; float z;

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

    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);

/*  Display display = getWindowManager().getDefaultDisplay();
    int imageSize = img.getWidth();
    Point size = new Point();
    display.getSize(size);
    viewWidth = size.x;
    viewHeight = size.y; */

}

private float mAccel; // acceleration apart from gravity
private float mAccelCurrent; // current acceleration including gravity
private float mAccelLast; // last acceleration including gravity

private final SensorEventListener mSensorListener = new SensorEventListener() {
    public void onSensorChanged(SensorEvent se) {
        float x = se.values[0];
        TextView TextX = (TextView) findViewById(R.id.TextX);
        TextX.setText(String.valueOf(x));
        float y = se.values[1];
        TextView TextY = (TextView) findViewById(R.id.TextY);
        TextY.setText(String.valueOf(y));
        float z = se.values[2];
        TextView TextZ = (TextView) findViewById(R.id.TextZ);
        TextZ.setText(String.valueOf(z));

        ImageView img = (ImageView) findViewById(R.id.imageView);

        //   TextX.setText(String.valueOf(x));  //ekran sallayınca x koordinatı değişecek.
        // float y = se.values[1];

        //  TextY.setText(String.valueOf(y)); //ekranı sallayınca y koordinati değişecek.
        // float z = se.values[2];

        //   TextZ.setText(String.valueOf(z)); //ekranı sallayınca z koordinatı değişecek.
        mAccelLast = mAccelCurrent;
        mAccelCurrent = (float) Math.sqrt((double) (x * x + y * y + z * z));
        float delta = mAccelCurrent - mAccelLast;
        mAccel = mAccel * 0.9f + delta; // perform low-cut filter

        //img.setZ(z);

       /* if (buttonX < viewWidth) { */
        //    buttonX -= x;
      /*  } */

       /* if (buttonY < viewHeight) { */
        //   buttonY += y;
    /*    } */

        // img.setX(buttonX);
        // img.setY(buttonY);

    }

Kod hata vermiyor ama nesne hareket etmiyor neden?