Called when sensor values have changed.
See {@link android.hardware.SensorManager SensorManager}
for details on possible sensor types.
See also {@link android.hardware.SensorEvent SensorEvent}.
NOTE: The application doesn't own the
{@link android.hardware.SensorEvent event}
object passed as a parameter and therefore cannot hold on to it.
The object may be part of an internal pool and may be reused by
the framework.