ReturnToTopDemoScrollListener.kt

recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrolled(recyclerView: RecyclerView?, dx: Int, dy: Int) {
                super.onScrolled(recyclerView, dx, dy)
                if ((recyclerView?.layoutManager as LinearLayoutManager)
                                .findFirstCompletelyVisibleItemPosition() == 0) {
                    buttonReturnToTop.visibility = View.GONE
                }
            }
        })