How to disable scrolling of AppBarLayout in CoordinatorLayout?

Question

I have MapFragment with parallax effect inside AppBarLayout:

I want to disable scrolling on AppBarLayout, because it is not possible to move across map, since touch evenys on the map are always handled as scroll events. I would like to handle collapsing of AppBarLayout by scrolling RecyclerView only, which is on the bottom of the screen.

This is my xml:

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    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="wrap_content"
        android:fitsSystemWindows="true"
        app:contentScrim="@color/white"
        app:expandedTitleMarginEnd="64dp"
        app:expandedTitleMarginStart="48dp"
        app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
        app:titleEnabled="false">

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_collapseMode="parallax"
            android:fitsSystemWindows="true">

            <fragment
                android:id="@+id/map"
                android:name="com.androidmapsextensions.SupportMapFragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
        </FrameLayout>

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="73dp"
            app:contentInsetLeft="0dp"
            app:contentInsetStart="0dp"
            app:layout_collapseMode="pin"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

            <include
                android:id="@+id/search_bar"
                layout="@layout/layout_searchbar" />
        </android.support.v7.widget.Toolbar>

        <View
            android:id="@+id/toolbar_shadow"
            android:layout_width="match_parent"
            android:layout_height="3dp"
            android:layout_below="@id/search_bar"
            android:layout_gravity="bottom"
            android:background="@drawable/toolbar_dropshadow"
            android:visibility="gone" />
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>


<RecyclerView
    android:id="@+id/farm_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

Thank you for the response.

Answer 1

I'm not sure I got it, but I think you are looking for a DragCallback.

The DragCallback interface allows to choose whether the sibling scrolling view should be controlled by scrolls onto the AppBarLayout.

You can define one by calling:

CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
behavior.setDragCallback(new AppBarLayout.Behavior.DragCallback() {
    @Override
    public boolean canDrag(@NonNull AppBarLayout appBarLayout) {
        return false;
    }
});

By always returning false, your scrolling view will not be controlled by the ABL any longer.

Note: before calling this you should check that ViewCompat.isLaidOut(appBarLayout), otherwise params.getBehavior() will return null.