RecyclerView滚动到顶部按钮

Question

I want to add back to top button in my app. I use recyclerview for displaying items. I added button and when I click on it, view is going to top, but my goal is to show this button only if application is scrolled down or up, and my first item is not visible (I hope thats clear explanation). I tried with

LayoutManager.findFirstCompletelyVisibleItemPosition();

and other methods for LayoutManager but without acceptable effects.

Answer 1

My solution is showed below. I add OnScrollListener on my RecyclerView, and when view is scrolled I check if the first item is visible and I set visibility of my button.

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

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        int visibility = (MyLayoutManager.findFirstCompletelyVisibleItemPosition() != 0) ? View.VISIBLE : View.GONE;
        btn.setVisibility(visibility);
    }
});