ViewPager in a NestedScrollView

Question

I need to create an interface like Google Newsstand which is a sort of ViewPager (horizontal scroll) over a collapsing header (vertical scroll). One of my requirements is to use the new Design Support Library presented at the Google IO 2015. (http://android-developers.blogspot.ca/2015/05/android-design-support-library.html)

Based on the sample created by Chris Banes (https://github.com/chrisbanes/cheesesquare) I've reach the point that I'm able to do the collapsing behaviour but with a basic LinearLayout (without horizontal scroll).

I tried to replace the LinearLayout by a ViewPager and I got a blank screen. I played with: width, weight and all kind of view groups but.... still a blank screen. It seems that ViewPager and NestedScrollView don't like each other.

I tried a workaround by using an HorizontalScrollView: it works but I loose the benefit of the PagerTitleStrip feature and the focus on a single panel (I can stop the horizontally between 2 panels).

Now I have no more ideas, if anyone can lead me to a solution...

Thanks

Here is my latest layout file :

<?xml version="1.0" encoding="utf-8"?>
<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:layout_width="match_parent"
        android:layout_height="@dimen/header_height"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <include
                layout="@layout/part_header"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_collapseMode="parallax"/>

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

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

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

        <android.support.v4.view.ViewPager
            android:id="@+id/activity_main_viewpager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#FFA0"/>


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

Answer 1

I meet this problem ,i solve it by setFillViewport (true)

<android.support.v4.widget.NestedScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="@+id/nest_scrollview"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="mio.kon.yyb.nestedscrollviewbug.ScrollingActivity"
tools:showIn="@layout/activity_scrolling">


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

in activity

  NestedScrollView scrollView = (NestedScrollView) findViewById (R.id.nest_scrollview);
    scrollView.setFillViewport (true);