res/layout/gallery_main.xml

<?xml version="1.0" encoding="utf-8"?>
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<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawerLayout"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

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

        <RelativeLayout
            android:id="@+id/gallery_root"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@+id/bottom_navigation">

            <!-- Toolbar -->
            <include layout="@layout/toolbar" />

            <!-- Main content -->
            <include layout="@layout/gl_root_group" />

        </RelativeLayout>

        <!-- Bottom bar -->
        <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottom_navigation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/primary"
            android:layout_alignParentBottom="true"
            app:menu="@menu/navigation_items"
            app:itemIconTint="@drawable/item_bg"
            app:itemTextColor="@drawable/item_bg" />

    </RelativeLayout>

</LinearLayout>