Single-Activity: Create Login Credentials (Jetpack Navigation)

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"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/navigation"/>

</FrameLayout>

create-login-credentials-fragment.kt

class CreateLoginCredentialsFragment : Fragment(R.layout.create_login_credentials_fragment) {
    private val viewModel by navGraphSavedStateViewModels(R.id.registration_graph) { handle -> // ViewModelUtils.kt
        Injector.get().registrationViewModelFactory().create(handle) // Dagger + AssistedInject
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
      
        val binding = CreateLoginCredentialsFragmentBinding.bind(view)
        // ...

create-login-credentials-viewmodel.kt

class RegistrationViewModel @AssistedInject constructor(
    private val authenticationManager: AuthenticationManager,
    @Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
    @AssistedInject.Factory
    interface Factory {
        fun create(savedStateHandle: SavedStateHandle): RegistrationViewModel
    }
  
    // ...
}

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/navigation"
    app:startDestination="@id/splash_graph"
    tools:ignore="UnusedNavigation">
  
    <!-- ... -->
    <navigation
        android:id="@+id/registration_graph"
        app:startDestination="@id/enter_profile_data_fragment">

        <action
            android:id="@+id/registration_to_logged_in"
            app:destination="@id/logged_in_graph"
            app:enterAnim="@anim/fragment_fade_enter"
            app:exitAnim="@anim/fragment_fade_exit"
            app:popEnterAnim="@anim/fragment_fade_enter"
            app:popExitAnim="@anim/fragment_fade_exit"
            app:popUpTo="@id/logged_out_graph"
            app:popUpToInclusive="true">
            <argument
               android:name="username"
               app:argType="string"
               app:nullable="false" />
        </action>

        <fragment
            android:id="@+id/create_login_credentials_fragment"
            android:name=".features.registration.CreateLoginCredentialsFragment"
            tools:layout="@layout/create_login_credentials_fragment" />
    </navigation>
</navigation>