How to detect the turnover motion in android?

This sample activity demonstrates how a device's gravity sensor can be used to detect when the device is turned over. In method onSensorChanged(), term factor determines how complete the "turn over" must be. Typical range might be 0.7 to 0.95.

Support for Gravity Sensor was added in Android API 9. Not all devices have a gravity sensor.

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private static final String TAG = "Demo";

    private SensorManager mSensorManager;
    private Sensor mGravitySensor;
    private boolean mFacingDown;

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // nothing
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        final float factor = 0.95F;

        if (event.sensor == mGravitySensor) {
            boolean nowDown = event.values[2] < -SensorManager.GRAVITY_EARTH * factor;
            if (nowDown != mFacingDown) {
                if (nowDown) {
                    Log.i(TAG, "DOWN");
                } else {
                    Log.i(TAG, "UP");
                }
                mFacingDown = nowDown;
            }
        }
    }

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

        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mGravitySensor = mSensorManager.getDefaultSensor(Sensor.TYPE_GRAVITY);

        if (mGravitySensor == null) {
            Log.w(TAG, "Device has no gravity sensor");
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (mGravitySensor != null) {
            mSensorManager.registerListener(this, mGravitySensor, SensorManager.SENSOR_DELAY_NORMAL);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        mSensorManager.unregisterListener(this);
    }
}