Implements a custom navigator host in an activity

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    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_height="match_parent"
    android:layout_width="match_parent">

    <fragment
        android:id="@+id/navigation_host"
        android:name="com.example.MyNavHostFragment"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/main_graph"
        tools:context=".MainActivity" />
</FrameLayout>