如何隐藏顶部回收器视图中的浮动操作按钮并在向下滚动时显示？

Question

我试图仅在 Recycler 视图向下滚动时显示一个浮动操作按钮，并在位置位于最顶部时隐藏。对不起，我的英语很糟糕

Answer 1

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx,int dy){
        super.onScrolled(recyclerView, dx, dy);

        if (dy >0) {
            // Scroll Down
            if (fab.isShown()) {
                fab.hide();
            }
        }
        else if (dy <0) {
            // Scroll Up
            if (!fab.isShown()) {
                fab.show();
            }
        }
     }
})

Answer 2

这里你可以做些什么来识别滚动状态

 recyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);

            if (!recyclerView.canScrollVertically(1) && newState==RecyclerView.SCROLL_STATE_IDLE) {

               //do what you want if recyclerview scrolled to bottom
            }else{

                //do what you want if recyclerview not scrolled to bottom
            }
        }
    });

Answer 3

为 recylerview 添加滚动监听器并在滚动时隐藏 fab

 fun hideFabWhenScroll(fab: FloatingActionButton, recyclerView: RecyclerView){
    recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
        override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
            if (dy > 0 || dy < 0 && fab.isShown) {
                fab.hide()
            }
        }

        override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
            if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                fab.show()
            }

            super.onScrollStateChanged(recyclerView, newState)
        }
    })
}