mobile_navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation 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/mobile_navigation"
    app:startDestination="@id/AFragment">

    <fragment
        android:id="@+id/AFragment"
        android:name="com.example.samplemediumapp.ui.a_fragment.AFragment"
        android:label="AFragment"
        tools:layout="@layout/fragment_a">
        <action
            android:id="@+id/action_AFragment_to_greetingDialog"
            app:destination="@id/greetingDialog" />
    </fragment>
    <dialog
        android:id="@+id/greetingDialog"
        tools:layout="@layout/dialog_greeting"
        android:name="com.example.samplemediumapp.ui.a_dialog.GreetingDialog"
        android:label="GreetingDialog" />
</navigation>