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

Answer 1

Add android:fillViewport="true" in your NestedScrollView . period.

Answer 2

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);

Answer 3

I was having a similar problem (but without CollapsingToolbarLayout, just a simple Toolbar + TabLayout within the AppBarLayout). I wanted the Toolbar to scroll out of sight when scrolling down the contents of a ViewPager within the NestedScrollView.

My layout went something like this:

<android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:animateLayoutChanges="true">

            <android.support.v7.widget.Toolbar
                android:id="@+id/my_toolbar"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_scrollFlags="scroll|enterAlways"/>

            <android.support.design.widget.TabLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/my_tab_layout"
                android:fillViewport="false"
                app:tabMode="fixed"/>
         </android.support.design.widget.AppBarLayout>

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

                <android.support.v4.view.ViewPager
                    android:id="@+id/my_view_pager"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                     app:layout_behavior="@string/appbar_scrolling_view_behavior">
                </android.support.v4.view.ViewPager>
         </android.support.v4.widget.NestedScrollView>

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

This layout wasn't working as intended, but I solved it by simply getting rid of the NestedScrollView and using a LinearLayout instead. It worked for me right away on Android Support Library v23.1.0. Here's how the layout ended up:

<android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:animateLayoutChanges="true">

            <android.support.v7.widget.Toolbar
                android:id="@+id/my_toolbar"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_scrollFlags="scroll|enterAlways"/>

            <android.support.design.widget.TabLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/my_tab_layout"
                android:fillViewport="false"
                app:tabMode="fixed"/>
         </android.support.design.widget.AppBarLayout>

         <LinearLayout
            android:orientation="vertical"
            android:id="@+id/container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginBottom="4dp"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

                <android.support.v4.view.ViewPager
                    android:id="@+id/my_view_pager"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                     app:layout_behavior="@string/appbar_scrolling_view_behavior">
                </android.support.v4.view.ViewPager>
         </LinearLayout>

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

PS: These were actually two layout files in my project. I copied and pasted them here and tried to structure them as it would look like in a single file. I'm sorry if I screwed up while copy-pasting but please let me know if that's the case so I can fix it.

Answer 4

After spending hours tried all of the suggestions above, finally I made it work. The key is putting NestedScrollView inside PageViewer, AND set layout_behavior to '@string/appbar_scrolling_view_behavior' for BOTH views. The final layout is like

<CoordinatorLayout>
    <ViewPager app:layout_behavior="@string/appbar_scrolling_view_behavior">
        <NestedScrollView fillViewport="true" app:layout_behavior="@string/appbar_scrolling_view_behavior">
            <Content>...</Content>
        </NestedScrollView>
    </ViewPager>
    <AppBarLayout>...</AppBarLayout>
</CoordinatorLayout>

Answer 5

I have the same wish, nest a ViewPager inside a NestedScrollView. But it doesn't work for me neither. In my case, the ViewPager is inside a Fragment so I can switch content depending on the interactions with the drawer. Of course, AppBar, collapse, etc and all new feature of support library must work.

If a user vertically scrolls a page in the pager, I want other pages to be scrolled the same, to give the user the overall impression that the pager itself scrolled.

What I did, which works, is that I no longer embed the ViewPager inside a NestedScrollView, instead, I embed the content of the contained fragments inside a NestedScrollView.

Then, in case of a scroll in one fragment, I inform the container of the new scrolling position, which stores it.

Finally, on a swipe left or right detected from the pager (using addOnPageChangeListener looking for drag states) I inform the target left or right fragment where it must scroll (based on the container knowledge of it) to be aligned from the fragment I come from.

Answer 6

Use below customized class to resolve your problem. Don't forget to call onRefresh() method on pagechangelistener.

public class ContentWrappingViewPager extends ViewPager
{
    private int width = 0;
    public ContentWrappingViewPager(Context context) {
        super(context);
    }

    public ContentWrappingViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        int height = 0;
        width = widthMeasureSpec;
        if (getChildCount() > getCurrentItem()) {
            View child = getChildAt(getCurrentItem());
            child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
            int h = child.getMeasuredHeight();
            if(h > height) height = h;
        }

        heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    public void onRefresh()
    {
        try {
            int height = 0;
            if (getChildCount() > getCurrentItem()) {
                View child = getChildAt(getCurrentItem());
                child.measure(width, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
                int h = child.getMeasuredHeight();
                if(h > height) height = h;
            }

            int heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
            ViewGroup.LayoutParams layoutParams = this.getLayoutParams();
            layoutParams.height = heightMeasureSpec;
            this.setLayoutParams(layoutParams);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}