findFirstVisibleItemPosition() returns 0 inside nestedScrollView

Question

I have a recyclerView inside nestedScrollView. I know it's a bad practice, but there are some cases, that I can handle only in this way.

<androidx.core.widget.NestedScrollView
    android:id="@+id/nestedScroll"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycler_data"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
            tools:itemCount="1"
            tools:listitem="@layout/item_favorite_tournament"
            tools:visibility="visible" />

</androidx.core.widget.NestedScrollView>

And here's my code. I'll show you the scroll part, where I need to get the firstVisibleItemPosition. But it returns 0.

private void initList(RecyclerView recycler, View labelNoResults) {
    recycler.setAdapter(mAdapter);
    recycler.setHasFixedSize(true);
    mListLayoutManager = Objects.requireNonNull((LinearLayoutManager) recycler.getLayoutManager());


    recycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            final int p = mListLayoutManager.findFirstVisibleItemPosition();
            Log.d("Tag_1", "Position: " + p);
        }
    });
}

I think the problem is because of nestedScrollView. So how can I get the visibleItemPosition form recyclerView? Thank you.

Answer 1

The easiest way to fix this would be to replace NestedScrollView by simply ScrollView. This of course will change the behavior of your layout, but it will show you the right position.

In case of NestedScrollView, findFirstVisibleItemPosition() always returns 0 and findLastVisibleItemPosition() always returns the last item in the RecyclerView despite whether they are visible to the user or not. This happens because RecyclerView placed inside NestedScrollView behaves like a ListView without doing any recycling. Meaning all items are visible at the same time because all of them are bind at the same time.