RecyclerView inside NestedScrollView is not scrolling up when Image is collapsed

Question

Here is a link to the whole project so that you can reproduce the problem: https://github.com/FaridArbai/TapExchange/tree/master/TapExchange

I would like to ask for help with an issue that I've been struggling with for about two days and yet found no solution in spite of the thorough research that I have done.

Basically, I have an AppBarLayout with a CollapsingToolbarLayout inside whose mission is to collapse a background image when the user scrolls down a RecyclerView of CardViews. The problem arises when I try to scroll down that RecyclerView once the Image is fully collapsed: It won't scroll if I touch one of the cardviews that compose the RecyclerView!

Here is the look with no collapse (here I can scroll with no problem):

Uncollapsed Image, able to scroll in any direction

And here is the look once the image is collapsed (here I cannot scroll down if my finger touches any cardview that compose the RecyclerView):

Collapsed Image, unable to scroll down if I touch one of the cardviews

The code for the whole layout:

    <?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".profiles.PersonalProfile"
    android:background="#FCFCFC">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/personal_appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/personal_collapsing"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
            app:contentScrim="?attr/colorPrimary"
            app:title=""
            app:titleEnabled="false">

            <ImageView
                android:id="@+id/personal_image_background"
                android:layout_width="match_parent"
                android:layout_height="340dp"
                android:scaleType="centerCrop"
                android:src="@drawable/profile_background"/>

            <android.support.v7.widget.Toolbar 
                android:id="@+id/personal_toolbar"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_collapseMode="pin"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:title="">

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal">
                    <Space
                        android:id="@+id/avatar_collapsed_target"
                        android:layout_width="40dp"
                        android:layout_height="40dp"
                        android:layout_marginLeft="0dp"/>

                    <TextView
                        android:id="@+id/personal_title"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:textSize="18dp"
                        android:layout_gravity="center"
                        android:layout_marginLeft="10dp"
                        android:text="Unknown Username"/>
                </LinearLayout>

            </android.support.v7.widget.Toolbar>

        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>


    <android.support.design.widget.FloatingActionButton
        android:id="@+id/section_selection_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        app:srcCompat="@drawable/ic_action_add" />


    <de.hdodenhof.circleimageview.CircleImageView
        android:id="@+id/personal_image_foreground"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_marginTop="120dp"
        android:layout_gravity="top|center_horizontal"
        android:src="@drawable/executive"
        app:collapsedTarget="@id/avatar_collapsed_target"
        app:layout_behavior="com.faridarbai.tapexchange.graphical.CollapsingAvatarBehavior"
        android:elevation="5dp"/>

    <LinearLayout
        android:id="@+id/personal_status"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_anchor="@id/personal_image_foreground"
        app:layout_anchorGravity="bottom|center"
        android:paddingTop="30dp">

        <TextView
            android:id="@+id/username_status"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Unknown Username"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
    </LinearLayout>

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/personal_nested_scroll_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:fillViewport="true">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/personal_sections_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="0dp" />

    </android.support.v4.widget.NestedScrollView>

</android.support.design.widget.CoordinatorLayout>

I am building with the API 25 and using GUI utilities from version 25.4.0. I would be extremely grateful if anybody can help.

Thanks

EDIT

I tried with SDK nº 27 and 27.1.1 building tools, supressed both "snap" and the NestedScrollView and still got the same problem: Once the background image has collapsed the RecyclerView is unable to scroll up if I initially put my finger on a CardView from the RecyclerView. This is quite odd because WhatsApp, Facebook and Telegram use a very similar Layout and they don't have this problem so there should be a well accepted work around.

Anyone to help?

Answer 1

why you are using RecyclerView inside NestedScrollView?!. if yo have more items with different layouts you can use recyclerView With different ViewTypes but i won't recommend to use it inside NestedScrollView try to use it Directly and don't forget to put this app:layout_behavior="@string/appbar_scrolling_view_behavior" in the recylerView and it will work.