ItemDecoration doesn't work inside NestedScrollView

Question

I have implemented RecyclerView with sticky headers and I did it through ItemDecoration. It works as expected in the case of stand-alone recycler view.

<LinearLayout ...>
    <androidx.recyclerview.widget.RecyclerView .../>
    <androidx.recyclerview.widget.RecyclerView ... /> // ItemDecoration is supposed to be here and it works excellent
</LinearLayout>

But I have two lists and I need to use NestedScrollView

<androidx.core.widget.NestedScrollView ...>
<LinearLayout ...>
    <androidx.recyclerview.widget.RecyclerView .../>
    <androidx.recyclerview.widget.RecyclerView ... /> // It doesn't work here
</LinearLayout>
</androidx.core.widget.NestedScrollView ...>

In this case ItemDecoration doesn't work.

I've found out next information:

onDrawOver's are not called on scrolling because RecyclerView.draw() is not called as well.
All items are created at same time (so Adapter creates view holders for all items in the data). It's bad, but it's not my main problem.
I tried to force calling recyclerview's redraw on scrolling but it doesn't work

Do you have any advice how to fix it?

UPD xml file:

<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    android:scrollbars="none">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/black_background_color"
        android:focusableInTouchMode="true"
        android:orientation="vertical">
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/menuNewsList"
            android:layout_width="match_parent"
            android:layout_height="170dp" />
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/listMenu"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center"
            app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />
    </LinearLayout>
</androidx.core.widget.NestedScrollView>

Code initialization:

listMenu.apply {
    adapter = dishAdapter
    isNestedScrollingEnabled = false
}
listMenu.addItemDecoration(HeaderItemDecoration(listMenu, isHeader = isHeader()))

HeaderItemDecoration was copied from there How can I make sticky headers in RecyclerView? (Without external lib)

Can you clear one thing, by "ItemDecoration doesn't work" do you mean the decoration headers don't render or it does but doesn't scroll as required. — ljk, Feb 24 '20 at 14:49
ItemDecoration doesn't render. Actually onDrawOver's are even not called — NIkita Nezhevskii, Feb 24 '20 at 16:55
Did you ever find a solution for this? Stuck with the same problem here. — Tharkius, Oct 14 '21 at 14:11

danmaze · Answer 1 · 2020-02-23T19:15:26.540

0

Shouldn't you add an ItemDecoration to a RecyclerView using the addDecoration(ItemDecoration decoration) method?

edited Feb 23 '20 at 19:15

answered Feb 23 '20 at 16:34

danmaze

319
3
8

I've added. In the first described case it works well. – NIkita Nezhevskii Feb 23 '20 at 17:36
Does the ItemDecoration work for the first RecyclerView, even if it's not actually supposed to be there? Have you tried that? – danmaze Feb 23 '20 at 18:40
Can you provide more details such as the attributes of the views and view group? I would have tried to replicate the problem but it's more difficult to that without more contextual information? – danmaze Feb 23 '20 at 19:17
First RecyclerView has a horizontal scrolling, so ItemDecoration won't work with it. But if move 2nd RecyclerView to the top it won't work as well. Also if remove NestedScrollView it works as expected – NIkita Nezhevskii Feb 24 '20 at 09:27
I've added more details to the my main question – NIkita Nezhevskii Feb 24 '20 at 09:27
did you fix this one, I am facing the same issue – Prasanna Narshim May 27 '20 at 06:38

ItemDecoration doesn't work inside NestedScrollView

1 Answers1