custom transition help

public class AlphaScale extends Visibility {
    @Override
    public Animator onAppear(ViewGroup sceneRoot, View view, TransitionValues startValues, TransitionValues endValues) {
      return createAlphaScaleAnimator (view, 0,1 );


    }

    @Override
    public Animator onDisappear(ViewGroup sceneRoot, View view, TransitionValues startValues, TransitionValues endValues) {
        return null;
    }

    private Animator createAlphaScaleAnimator(View view, float fromScale, float toScale, float fromAlpha, float toAlpha) {
        AnimatorSet set = new AnimatorSet();
        ObjectAnimator x = ObjectAnimator.ofFloat(view, View.SCALE_X, fromScale, toScale);
        ObjectAnimator y = ObjectAnimator.ofFloat(view, View.SCALE_Y, fromScale, toScale);
        ObjectAnimator alpha = ObjectAnimator.ofFloat(view, View.ALPHA, fromAlpha, toAlpha);
        set.playTogether(x, y, alpha);
        return set;
    }
}