onSensorChanged() for accelerometer demo

gistfile1.java

@Override
public void onSensorChanged(SensorEvent event) {
	if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
		if (isShakeDetected(event)) {
			// If we detected a shake, update to the next background color.
			mBackgroundColorIndex = (mBackgroundColorIndex + 1) % mBackgroundColorArray.length;
			mTargetView.setBackgroundColor(mBackgroundColorArray[mBackgroundColorIndex]);
		}
	}
}

/*
 * This function determines whether the accelerometer detected a force of
 * greater than SHAKE_FORCE_THRESHOLD_IN_G, which we will consider to be a shake.
 * For details of the information returned by the accelerometer and how to use it, 
 * please see the android documentation at:
 * http://developer.android.com/guide/topics/sensors/sensors_motion.html
 *
 */
private boolean isShakeDetected(SensorEvent event){
	float[] values = event.values;
	float x = values[0];
	float y = values[1];
	float z = values[2];

	float numberOfGsDetected = (x * x + y * y + z * z)
			/ (SensorManager.GRAVITY_EARTH * SensorManager.GRAVITY_EARTH);
	if (numberOfGsDetected >= SHAKE_FORCE_THRESHOLD_IN_G)
	{
		long currentMs = System.currentTimeMillis();
		if ((currentMs - mLastUpdateMs) > MAX_COLOR_CHANGE_FREQUENCEY_MS) {
			mLastUpdateMs = currentMs;
			return true;
		}
	}

	return false;
}