[android] How to refresh app upon shaking the device?

I have tried several implementations, but would like to share my own. It uses G-force as unit for the threshold calculation. It makes it a bit easier to understand what is going on, and also with setting a good threshold.

It simply registers a increase in G force and triggers the listener if it exceeds the threshold. It doesn't use any direction thresholds, cause you don't really need that if you just want to register a good shake.

Of-course you need the standard registering and UN-registering of this listener in the Activity.

Also, to check what threshold you need, I recommend the following app (I am not in any way connected to that app)

    public class UmitoShakeEventListener implements SensorEventListener {

    /**
     * The gforce that is necessary to register as shake. (Must include 1G
     * gravity)
     */
    private final float shakeThresholdInGForce = 2.25F;

    private final float gravityEarth = SensorManager.GRAVITY_EARTH;

    private OnShakeListener listener;

    public void setOnShakeListener(OnShakeListener listener) {
        this.listener = listener;
    }

    public interface OnShakeListener {
        public void onShake();
    }

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

    }

    @Override
    public void onSensorChanged(SensorEvent event) {

        if (listener != null) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            float gX = x / gravityEarth;
            float gY = y / gravityEarth;
            float gZ = z / gravityEarth;

            //G-Force will be 1 when there is no movement. (gravity)
            float gForce = FloatMath.sqrt(gX * gX + gY * gY + gZ * gZ); 



            if (gForce > shakeThresholdInGForce) {
                listener.onShake();

            }
        }

    }

}