How to collapse content of AppBarLayout but not Toolbar

Question

Here is my application screen:

And layout xml:

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

<android.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:animateLayoutChanges="true">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:title="@string/app_name"
        app:theme="@style/Toolbar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Dark" />

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

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="16dp"
    android:src="@drawable/arrow_right_bold"
    app:fabSize="normal" />

And I want to collapse the only content while scrolling.

I figure out that I can move Toolbar out of AppBarLayout but whether there is a clear way? Otherwise, I will be forced set toolbar background color. I haven't any problem with it, but I think that it's some kind of dirty solution :)

So. How to collapse content of AppBarLayout but not Toolbar?

Answer 1

If I understood correctly, you want to collapse a portion of the header when scrolling. If that's the case, @Nerd's comment links to a good tutorial on how to do that. Anyway, I'll leave here an example of CoordinatorLayout usage that does what you are looking for:

<?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:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true"
        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"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <FrameLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent">

                <!-- PUT HERE THE PORTION OF THE HEADER YOU WANT TO COLLAPSE WHEN SCROLLING-->
            </FrameLayout>

            <android.support.v7.widget.Toolbar
                android:id="@+id/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/scroll"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clipToPadding="false"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <!-- YOUR SCROLLABLE CONTENT HERE -->
    </android.support.v4.widget.NestedScrollView>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:clickable="true"
        app:layout_anchor="@id/app_bar_layout"
        app:layout_anchorGravity="bottom|right|end"/>
</android.support.design.widget.CoordinatorLayout>