CoordinatorLayout not working well with NestedScrollView and viewpager

Question

Recently, I used Android Design Support Library and I have the following code for my collapsing toolbar.

<android.support.design.widget.CoordinatorLayout
    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.support.design.widget.AppBarLayout
        android:id="@+id/media_detail_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/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:contentScrim="?attr/colorPrimary"
            >

            <include
                layout="@layout/layout_card"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                />

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

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

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        >

        <android.support.design.widget.TabLayout
            android:id="@+id/media_detail_tabs"
            android:layout_width="match_parent"
            android:layout_height="?android:attr/actionBarSize"
            android:background="@color/blue_2"
            app:tabMode="scrollable"
            />

        <android.support.v4.view.ViewPager
            android:id="@+id/view_pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />

    </LinearLayout>

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

I have two fragments for the View Pager. One is NestedScrollView and the other is Recycler View. My issue is the NestedScrollView, here's the code below.

<android.support.v4.widget.NestedScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        >
    </LinearLayout>
</android.support.v4.widget.NestedScrollView>

My issue is that when you scroll the view up, as soon as your finger moves a bit on the side, it triggers the horizontal scroll for the view pager. Could you please help me to avoid that ? When we scroll up and down, the view pager shouldn't be triggered. It works well in my recycler view fragment. Thanks.

Answer 1

I tried same layout with the latest version of these libraries

compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:design:23.1.1'

and it works well as expected, that is:

if the gesture is mainly vertical scroll (even diagonal) NestedScrollView triggers the scroll, otherwise if the gesture is mainly horizontal swipe (even with a minimal vertical gap) ViewPager triggers the swipe. To solve upgrade your libraries.