Android: Can a NestedScrollView along with a CollapsingToolbarLayout have a non-rectangular background?

Question

Android

If you bind NestedScrollView to CollapsingToolbarLayout then they cannot be separated from each other. But the problem is that if you set the NestedScrollView to the top of the View that is not a rectangle, for example , then this gap occurs . As intended, it should look like this . If you stretch the CollapsingToolbarLayout down, then this View will also move, but this should not happen.

<com.google.android.material.appbar.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="126dp"
    android:fitsSystemWindows="true">

    <com.google.android.material.appbar.CollapsingToolbarLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/cyan"
        android:fitsSystemWindows="true"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"
        app:toolbarId="@+id/toolbar">

        <carbon.widget.RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_collapseMode="parallax">

            <!-- content of AppBarLayout-->

        </carbon.widget.RelativeLayout>

    </com.google.android.material.appbar.CollapsingToolbarLayout>

</com.google.android.material.appbar.AppBarLayout>

<androidx.core.widget.NestedScrollView
    android:id="@+id/nested_scroll_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:overScrollMode="never"
    android:scrollbars="none"
    app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">

    <!-- content of NestedScrollView -->

</androidx.core.widget.NestedScrollView>

Answer 1

try making the fab button
app:layout_anchor="@+id/app_bar"
app:layout_anchorGravity="bottom|right|end"