IssueTracker

Able to reproduce the issue from your description, video attached (though I'm not able to see yours, I assume they're similar).

The problem is that when the list shortens to be smaller than the viewport, the AsyncPagedListDiffer doesn't receive any signals that tell it that more needs to be loaded - it currently only loads in response to getItem(). Will fix this, but in the meantime you can workaround this by calling getItem() in onCurrentListChanged:


class MyAdapter extends PagedListAdapter<...> {

    int lastPos = 0;

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        lastPos = position;
        // ... regular bind code ...
    }

    @Override
    public void onCurrentListChanged(@Nullable PagedList<Item> currentList) {
        // trigger load around most recently bound item
        getItem(Math.min(lastPos, getItemCount() - 1));
    }
}

In general, using a larger initial load size/prefetch distance avoids this problem as well.

We recommend page size to be several viewports worth of items ( https://developer.android.com/reference/androidx/paging/PagedList.Config.Builder#setPageSize(int) ). If you follow that, you'll typically avoid this problem, as initial load size + prefetch are >= page size by default.

Fix merged, will likely go out after 2.0: https://android-review.googlesource.com/c/platform/frameworks/support/+/760841

Again though, I'd like to reiterate that the ideal fix is, on the app side, using a large enough initial load size that this doesn't happen.