fragment_bottom_nav.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/bottom_nav_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.android.navigationsamples.BottomNavFragment">

    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/bottom_nav_toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimary"
        app:menu="@menu/toolbar"
        app:titleTextColor="@android:color/white" />


    <!-- Do not add: app:navGraph="@navigation/graph"
    or: android:name="androidx.navigation.fragment.NavHostFragment" -->
    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/bottom_nav_container"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/white"
        app:menu="@menu/bottom_nav" />
</LinearLayout>