beauty_recycle.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        if (dy > 0 && floatingActionButton.getVisibility() == View.VISIBLE){
            floatingActionButton.hide();
        }else if (dy < 0 && floatingActionButton.getVisibility() != View.VISIBLE){
            floatingActionButton.show();
        }
    }
 

});

給RecycleView設定監聽。

滑動置頂

fab_data.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        re_data.smoothScrollToPosition(0);
    }
});