Changing of color is very pretty and cool looking any application. it’s focus to users and attract. below the code for you. This code help to create color changing animation on fab button.

final ObjectAnimator animator = ObjectAnimator.ofInt(_fab, "backgroundTint", Color.rgb(0, 121, 107), Color.rgb(226, 143, 34));
animator.setEvaluator(new ArgbEvaluator());
animator.setInterpolator(new DecelerateInterpolator(2));
animator.addUpdateListener(new ObjectAnimator.AnimatorUpdateListener() {
    public void onAnimationUpdate(ValueAnimator animation) {
        int animatedValue = (int) animation.getAnimatedValue();

To use this code in sketchwere add add source directly block.