recyclerview中的cardview阴影高程动画

Question

我想要 cardview elevation 动画，就像 Google 在“PlayGames”动画中所做的那样。这是动画的示例gif。谁能指导我如何做或参考任何图书馆。

sample gif animation

谢谢

Answer 1

怎么做？ 使用 Viewpager 和阴影变换

1- 为卡片视图创建一个PagerAdapter

2- 在适配器内部instantiateItem 方法为卡设置高程像这样

 CardView cardView = (CardView) view.findViewById(R.id.cardView);

        if (mBaseElevation == 0) {
            mBaseElevation = cardView.getCardElevation();
        }

        cardView.setMaxCardElevation(mBaseElevation * MAX_ELEVATION_FACTOR);
        mViews.set(position, cardView);
        return view;

之后实现ViewPager.OnPageChangeListener 里面onPageScrolled

        if (currentCard != null) {
            if (mScalingEnabled) {
                currentCard.setScaleX((float) (1 + 0.1 * (1 - realOffset)));
                currentCard.setScaleY((float) (1 + 0.1 * (1 - realOffset)));
            }
            currentCard.setCardElevation((baseElevation + baseElevation
                    * (CardAdapter.MAX_ELEVATION_FACTOR - 1) * (1 - realOffset)));
        }

        CardView nextCard = mAdapter.getCardViewAt(nextPosition);

        // We might be scrolling fast enough so that the next (or previous) card
        // was already destroyed or a fragment might not have been created yet
        if (nextCard != null) {
            if (mScalingEnabled) {
                nextCard.setScaleX((float) (1 + 0.1 * (realOffset)));
                nextCard.setScaleY((float) (1 + 0.1 * (realOffset)));
            }
            nextCard.setCardElevation((baseElevation + baseElevation
                    * (CardAdapter.MAX_ELEVATION_FACTOR - 1) * (realOffset)));
        }

完整代码ViewPagerCards

如果你想这样做，请使用RecyclerView
你可以得到中间项目并检查onBindViewHolder如果该项目是中间项目然后做缩放动画 要知道得到中间检查这个答案： Get center visible item of RecycleView when scrolling