Animation utility for showing and hiding a View with a slide animation, used for Views that are anchored to the bottom of the screen overlaying the main content, usually confirmation buttons.

AnimationUtils.java

public class AnimationUtils {

    private static final int SLIDE_DURATION = 150;
    private static final int FADE_DURATION = 100;
    private static final ArrayMap<View, ObjectAnimator> showing = new ArrayMap<>();
    private static final ArrayMap<View, ObjectAnimator> hiding = new ArrayMap<>();

    private AnimationUtils() {
    }

    private static boolean isRunning(View view, ArrayMap map) {
        return map.containsKey(view);
    }

    private static long cancelAnimations(View view, ArrayMap<View, ObjectAnimator> map) {
        ObjectAnimator anim = map.remove(view);
        long duration = 0;
        if (anim != null) {
            duration = anim.getCurrentPlayTime();
            anim.cancel();
        }
        return duration;
    }

    private static void adjustPlayTime(ObjectAnimator anim, long elapsed) {
        if (elapsed > 0) {
            anim.setCurrentPlayTime(anim.getDuration() - elapsed);
        }
    }

    public static void slideUp(View view) {
        if (isRunning(view, showing) || view.getVisibility() == View.VISIBLE && !isRunning(view, hiding)) {
            return;
        }

        int height = view.getHeight();
        if (height == 0) {
            view.measure(makeMeasureSpec(0, UNSPECIFIED), makeMeasureSpec(0, UNSPECIFIED));
            height = view.getMeasuredHeight();
        }

        long elapsed = cancelAnimations(view, hiding);
        ObjectAnimator anim = ObjectAnimator.ofFloat(view, "translationY", height, 0f);
        anim.setDuration(SLIDE_DURATION);
        adjustPlayTime(anim, elapsed);
        anim.addListener(new ViewObjectAnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation, View view) {
                view.setVisibility(View.VISIBLE);
            }

            @Override
            public void onAnimationEnd(Animator animation, View view) {
                view.setTranslationY(0f);
                showing.remove(view);
            }
        });
        anim.start();
        showing.put(view, anim);
    }

    public static void slideDown(View view) {
        if (isRunning(view, hiding) || view.getVisibility() == View.GONE) {
            return;
        }

        long elapsed = cancelAnimations(view, showing);
        ObjectAnimator anim = ObjectAnimator.ofFloat(view, "translationY", 0f, view.getHeight());
        anim.setDuration(SLIDE_DURATION);
        adjustPlayTime(anim, elapsed);
        anim.addListener(new ViewObjectAnimatorListener() {
            @Override
            public void onAnimationEnd(Animator animation, View view) {
                view.setVisibility(View.GONE);
                view.setTranslationY(0f);
                hiding.remove(view);
            }
        });
        anim.start();
        hiding.put(view, anim);
    }

    public static void fadeIn(View view) {
        if (isRunning(view, showing) || view.getVisibility() == View.VISIBLE && !isRunning(view, hiding)) {
            return;
        }

        long elapsed = cancelAnimations(view, hiding);
        ObjectAnimator anim = ObjectAnimator.ofFloat(view, "alpha", 0f, 1f);
        anim.setDuration(FADE_DURATION);
        adjustPlayTime(anim, elapsed);
        anim.addListener(new ViewObjectAnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation, View view) {
                view.setVisibility(View.VISIBLE);
            }

            @Override
            public void onAnimationEnd(Animator animation, View view) {
                view.setAlpha(1f);
                showing.remove(view);
            }
        });
        anim.start();
        showing.put(view, anim);
    }

    public static void fadeOut(View view, int visibility) {
        if (isRunning(view, hiding) || view.getVisibility() == visibility) {
            return;
        }

        long elapsed = cancelAnimations(view, showing);
        ObjectAnimator anim = ObjectAnimator.ofFloat(view, "alpha", 1f, 0f);
        anim.setDuration(FADE_DURATION);
        adjustPlayTime(anim, elapsed);
        anim.addListener(new ViewObjectAnimatorListener() {
            @Override
            public void onAnimationEnd(Animator animation, View view) {
                view.setVisibility(visibility);
                view.setAlpha(1f);
                hiding.remove(view);
            }
        });
        anim.start();
        hiding.put(view, anim);
    }
}