public interface AnimationStepListener
onStep(int) method will be called with a value between the given start and stop. Whatever the way
(forward or backward), this value goes from start to stop.
start- the animation start value.
stop- the animation stop value.
from- the widget before the animation.
to- the widget after the animation.
trueif going forward,
void onStep(int value)
value- the step value.