Scrollable Recycler view and view pager

Question

I have a screen where i need to display a toolbar at the top, a slideshow below the toolbar and a recyclerview below the slideshow. For displaying the slideshow I am using a viewPager which slides images horizontally.

The problem I am currently facing is that when the recyclerview is scrolled the viewPager needs to scroll with it and the toolbar should stay pinned.

I tried putting the viewPager and the recyclerview inside a nested Scroll but since a nested scroll requires a single child i had to put both the viewpager and recyclerview inside a linear layout because of which the scrolling behaviour of the recyclerview went for a toss ( i am monitoring the recyclerview scroll so i can load more results when it reaches the bottom ).

Answer 1

You can solve this problem by using CoordinatorLayout , AppBarLayout , and CollapsingToolbarLayout . You put your Toolbar and ViewPager in the CollapsingToolbarLayout , and you use the RecyclerView as the scrolling sibling to the AppBarLayout so that it can correctly collapse the ViewPager .

Here's some example XML I used to achieve what I think you described:

<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="wrap_content">

        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <android.support.v4.view.ViewPager
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:layout_marginTop="?attr/actionBarSize"/>

            <android.support.v7.widget.Toolbar
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_collapseMode="pin"/>

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

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

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        app:layoutManager="LinearLayoutManager"/>

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

The only tricky bit is that the <Toolbar> tag has to come after the <ViewPager> tag, since they're both inside a view that derives from FrameLayout . Normally, this would mean that the toolbar obscures the top portion of the viewpager, but the viewpager's marginTop attribute stops that from happening.