private void adjustFilterEmptyView() {
        final boolean listIsEmpty = filterListAdapter.getItemCount() == 0;
        binding.filterList.setVisibility(listIsEmpty ? View.GONE : View.VISIBLE);
        binding.filterListEmpty.setVisibility(!listIsEmpty ? View.GONE : View.VISIBLE);
    }
Show a filter selection using an {@code ExpandableListView}.
main/src/main/java/cgeo/geocaching/filters/gui/GeocacheFilterActivity.java