Custom Layout Behavior

A custom behavior can be useful when the CoordinatorLayout contains non standard elements, which we want to move together with the bottom navigation view.

For instance, given this example:

You'll notice that I've used a non standard Floating Action Button. I'm using the FloatingActionMenu component.

This is my resource layout setup:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout android:id="@+id/CoordinatorLayout01"
    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:layout_height="match_parent"
    android:fitsSystemWindows="true">

    .... appbar layout and content here ....

    <com.github.clans.fab.FloatingActionMenu
        android:id="@+id/fab"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        app:menu_labels_singleLine="true">

        <com.github.clans.fab.FloatingActionButton
            android:id="@+id/fab_item1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@android:drawable/ic_menu_camera"
            app:fab_label="Menu item 2"
            app:fab_size="mini" />

        <com.github.clans.fab.FloatingActionButton
            android:id="@+id/fab_item2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@android:drawable/ic_menu_call"
            app:fab_label="Lorem Ipsum"
            app:fab_size="mini" />

    </com.github.clans.fab.FloatingActionMenu>

    <it.sephiroth.android.library.bottomnavigation.BottomNavigation
        android:id="@id/BottomNavigation"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="bottom"
        app:bbn_badgeProvider="@string/bbn_badgeProvider"
        app:bbn_entries="@menu/bottombar_menu_4items"
        app:layout_behavior="it.sephiroth.android.library.bottomnavigation.app.behaviors.BottomNavigationCustomBehavior" />

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

As you can see in this line: app:layout_behavior="it.sephiroth.android.library.bottomnavigation.app.behaviors.BottomNavigationCustomBehavior" a custom layout behavior is being used for the BottomNavigation. The class itself is just an extension of the built-in BottomBehavior:

public class BottomNavigationCustomBehavior extends BottomBehavior {

    @SuppressWarnings ("unused")
    public BottomNavigationCustomBehavior(final Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
    }

    @Override
    protected boolean isFloatingActionButton(final View dependency) {
        return super.isFloatingActionButton(dependency) || dependency instanceof FloatingActionMenu;
    }
}