public class ActivityMain extends Activity {
    protected static final long DEFAULT_WAIT_TIMEOUT_MS = 1000;

    private final DefaultServiceConnectionListener mConnectionListener =
            new DefaultServiceConnectionListener();

    private Car                 car;
    private TextView            textView;


    private CarSensorManager.OnSensorChangedListener    onSensorChangedListener =
            carSensorEvent -> textView.setText(carSensorEvent.toString());
    private CarSensorManager                            carSensorManager;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.display_txt);
        car = Car.createCar(this, mConnectionListener, null);
        car.connect();
        try {
            mConnectionListener.waitForConnection(DEFAULT_WAIT_TIMEOUT_MS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (carSensorManager != null)
            carSensorManager.unregisterListener(onSensorChangedListener);
    }

    protected class DefaultServiceConnectionListener implements ServiceConnection {
        private final Semaphore mConnectionWait = new Semaphore(0);

        public void waitForConnection(long timeoutMs) throws InterruptedException {
            mConnectionWait.tryAcquire(timeoutMs, TimeUnit.MILLISECONDS);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            System.out.println(name.getShortClassName());
        }

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            System.out.println(name.getShortClassName());
            mConnectionWait.release();
            try {
                carSensorManager = (CarSensorManager) car.getCarManager(Car.SENSOR_SERVICE);
                int[] supportedSensors = carSensorManager.getSupportedSensors();
                for (int sensor: supportedSensors) {
                    carSensorManager.registerListener(onSensorChangedListener, sensor, CarSensorManager.SENSOR_RATE_NORMAL);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}