Android sensors return the same values for every app opening

Question

Every time I open my app, I get the device's orientation values. If I turn the device 90 degrees to the right at the X-axis, the values change as well. But every time I reopen my app, it shows that the X value is 348. Even if I rotated the phone 90 degrees before opening my app. Why do the sensors return the same value at the start?

Whu every time I entry the app, the starting points are always the same?

I rotated the device before opening the app to 0 degrees and got:

I rotated the device before opening the app to 90 degrees and got:

I'm rotating the correct axis, this is not the problem

My code:

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

        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);

        sensorManager.registerListener(MainActivity.this, sensor, SensorManager.SENSOR_DELAY_FASTEST);
    }

    @Override
    public void onSensorChanged(SensorEvent event) { // Activated every changes in sensors
        Log.i(TAG, event.values[0] + " | " + event.values[1] + " | " + event.values[2]); // Prit the sensors values
    }

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

    }

Answer 1

Does this do what you wanted it to do?

I am just registering the listener in onStart and unregistering the listener in onStop and reading the sensorEvent value for the x-axis.

class MainActivity : AppCompatActivity() {

    private var sensorManager: SensorManager? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager?
    }

    override fun onStart() {
        super.onStart()

        val sensorAccelerometer = sensorManager?.getDefaultSensor(Sensor.TYPE_ORIENTATION)
        if (sensorAccelerometer != null) {
            sensorManager?.registerListener(sensorEventListener, sensorAccelerometer, SensorManager.SENSOR_DELAY_UI)
        } else {
            // No accelerometer available
        }
    }

    override fun onStop() {
        super.onStop()

        sensorManager?.unregisterListener(sensorEventListener)
    }

    private val sensorEventListener: SensorEventListener = object : SensorEventListener {

        override fun onSensorChanged(sensorEvent: SensorEvent?) {
            val rotationX = sensorEvent?.values?.get(0)?.toInt()

            // I am writing the int value to a TextView in the UI
            findViewById<TextView>(R.id.text_view_rotation_x).text = String.format(Locale.ENGLISH, "$rotationX")
        }

        override fun onAccuracyChanged(sensor: Sensor?, accuracy: Int) {
            // Do something
        }
    }
}