recyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
                            @Override
                            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                                super.onScrolled(recyclerView, dx, dy);
                                if (dy > 0) {
                                    buttontop.setVisibility(View.VISIBLE);
                                }
                                if (dy < 0){
                                    buttontop.setVisibility(View.GONE);
                                }
                            }
                        });