private void scrollAndAnimateBy(int increment) {
        if(loadingDone && (scrollerTimer == null || !scrollerTimer.isRunning())) {
            int index = avatarIndex + increment;
            if(index < 0)
                index = 0;
            else if(index >= avatars.size())
                index = avatars.size() - 1;

            DrawableAvatar drawable = null;

            if (drawableAvatars != null) {
                for(DrawableAvatar avatar: drawableAvatars) {
                    if(avatar.index == index) {
                        drawable = avatar;
                        break;
                    }
                }
            }
            if (drawable != null) {
                scrollAndAnimate(drawable);
            }
        }
    }