实现底部栏动态跟随列表显示隐藏

// 动画工具类
public class AnimatorUtil {

    private static LinearOutSlowInInterpolator FAST_OUT_SLOW_IN_INTERPOLATOR = new LinearOutSlowInInterpolator();

    private static AccelerateInterpolator LINER_INTERPOLATOR = new AccelerateInterpolator();


    /**
     * 显示view
     *
     * @param view View
     * @param viewPropertyAnimatorListener ViewPropertyAnimatorListener
     */
    public static void scaleShow(View view, ViewPropertyAnimatorListener viewPropertyAnimatorListener) {
        view.setVisibility(View.VISIBLE);
        ViewCompat.animate(view)
                .scaleX(1.0f)
                .scaleY(1.0f)
                .alpha(1.0f)
                .setDuration(800)
                .setListener(viewPropertyAnimatorListener)
                .setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR)
                .start();
    }

    /**
     * 隐藏view
     *
     * @param view View
     * @param viewPropertyAnimatorListener ViewPropertyAnimatorListener
     */
    public static void scaleHide(View view, ViewPropertyAnimatorListener viewPropertyAnimatorListener) {
        ViewCompat.animate(view)
                .scaleX(0.0f)
                .scaleY(0.0f)
                .alpha(0.0f)
                .setDuration(800)
                .setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR)
                .setListener(viewPropertyAnimatorListener)
                .start();
    }

    /**
     * 显示view
     *
     * @param view View
     * @param viewPropertyAnimatorListener ViewPropertyAnimatorListener
     */
    public static void translateShow(View view, ViewPropertyAnimatorListener viewPropertyAnimatorListener) {
        if (view.getVisibility()==View.VISIBLE){
            return;
        }
        view.setVisibility(View.VISIBLE);
        ViewCompat.animate(view)
                .translationY(0)
                .setDuration(400)
                .setListener(viewPropertyAnimatorListener)
                .setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR)
                .start();
    }

    /**
     * 隐藏view
     *
     * @param view View
     * @param viewPropertyAnimatorListener ViewPropertyAnimatorListener
     */
    public static void translateHide(View view, ViewPropertyAnimatorListener viewPropertyAnimatorListener) {
        if (view.getVisibility()==View.GONE){
            return;
        }
        view.setVisibility(View.GONE);
        ViewCompat.animate(view)
                .translationY(360)
                .setDuration(400)
                .setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR)
                .setListener(viewPropertyAnimatorListener)
                .start();
    }
}

然后就是页面代码

LinearLayout bootomView=findByid(R.id.xx)

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull final RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                // 第一种，直接取消动画
                RecyclerView.ItemAnimator animator = mRecyclerView.getItemAnimator();
                if (animator instanceof SimpleItemAnimator) {
                    ((SimpleItemAnimator) animator).setSupportsChangeAnimations(false);
                }
                mRecyclerView.getItemAnimator().setChangeDuration(0);
            }

            @Override
            public void onScrolled(@NonNull final RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                Log.e("tag", "当前滚动状态:" + recyclerView.getScrollState() + "当前位置:" + dy);
                 //上滑
                if (dy > 0) {
                    getActivity().runOnUiThread(() -> {
                        AnimatorUtil.translateHide(bootomView, null);
                    });
                } else if (dy < -1) {
                    //下滑
                    getActivity().runOnUiThread(() -> {
                        AnimatorUtil.translateShow(bootomView, null);
                    });
                }
                //底部数据特效
                LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
                int childCount = layoutManager.getChildCount();
                //对每个item进行初始化
                for (int i = 0; i < childCount; i++) {
                    layoutManager.getChildAt(i).setAlpha(1);
                    layoutManager.getChildAt(i).setScaleY(1);
                    layoutManager.getChildAt(i).setScaleX(1);
                }
                new ThreadPoolUtils().ioExecutor.execute(() -> {
                    calculateAlphaAndScale(recyclerView, layoutManager);
                });
            }
        });

// 底部数据动态缩放模糊动画效果
 private void calculateAlphaAndScale(RecyclerView recyclerView, LinearLayoutManager layoutManager) {
        LinearLayoutManager manager = (LinearLayoutManager) recyclerView.getLayoutManager();
        int firstItemPosition = manager.findFirstVisibleItemPosition();
        int lastItemPosition = manager.findLastVisibleItemPosition();
        View lastView = manager.getChildAt(lastItemPosition - firstItemPosition);
        if (lastView != null) {
            int itemHeight = lastView.getHeight();
            int visibleHeight = recyclerView.getHeight() - lastView.getTop();
            if (visibleHeight < 0) {
                return;
            }
            float ratio = visibleHeight * 1.0f / itemHeight;
            if (ratio > 1.0) {
                return;
            }
            lastView.setAlpha(ratio);
            float scale = 0.9f;
            float scaleFactor = scale + (1 - scale) * ratio;

            lastView.setScaleX(scaleFactor);
            lastView.setScaleY(scaleFactor);
        }
    }