VR Motion Test [Part 1] (Android Studio - Java)

I made an extremely simple app that gets the exact angle in degrees of your android based phone / tablet device and displays the resulted values of azimuth, pitch, and roll in the TextView which can be used for Virtual Reality based apps. My next app that I will display will actually demonstrate this in a real 3D world done in OpenGL ES 3.0 (Coming Soon):

Java Code:

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.WindowManager;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity implements SensorEventListener{
 
    private SensorManager sensorManager;
 
    float[] rotMatrix = new float[9];
    float[] radianValues = new float[3];
 
    TextView textView;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        textView = findViewById(R.id.textView);
    }
 
    @Override
    protected void onPause() {
        super.onPause();
 
        // Don't receive any more updates from either sensor.
        sensorManager.unregisterListener(this);
    }
 
    //when this Activity starts
    @Override
    protected void onResume()
    {
        super.onResume();
 
        sensorManager.registerListener(this , sensorManager.getDefaultSensor(Sensor.TYPE_GAME_ROTATION_VECTOR), SensorManager.SENSOR_DELAY_NORMAL);
    }
 
    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_GAME_ROTATION_VECTOR) {
                SensorManager.getRotationMatrixFromVector(rotMatrix, event.values);
                SensorManager.remapCoordinateSystem(rotMatrix,
                        SensorManager.AXIS_X, SensorManager.AXIS_Y, rotMatrix);
                SensorManager.getOrientation(rotMatrix, radianValues);
                float azimuth = (float) Math.toDegrees(radianValues[0]);
                float pitch = (float) Math.toDegrees(radianValues[1]);
                float roll = (float) Math.toDegrees(radianValues[2]);
                textView.setText(getString(R.string.vr, azimuth, pitch, roll));
        }
    }
 
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
 
    }
}