Android navigation component resets to start destination after configuration change

Question

I am using the Android navigation component and I have an activity with three fragments if I am in the second fragment and rotate the screen forcing the activity to restart the navigation is returned to the start destination.

shouldn't the navhostFragment retain the state of the graph when the activity restarts?

or is what is happening the default behavior here?

I don't want to add the following even though adding it "works"

 android:configChanges="orientation|screenSize|screenLayout|keyboardHidden"

because I don't want to handle orientation changes myself, I want it to be handled by the system normally and still retain the navigation state

I will provide some of my code if that helps

in the activity I use navController.setGraph() so I can pass data to the start destination like this

 navController = Navigation.findNavController(
        this,
        R.id.nav_host_fragment
    )
 setSupportActionBar(findViewById(R.id.toolbar))
 appBarConfiguration = AppBarConfiguration.Builder(navController.graph).build()
 supportActionBar?.setDisplayHomeAsUpEnabled(true)

 intent.putExtra("EXTRA_KEY","some_data")
 navController.setGraph(R.navigation.nav_graph,intent.extras)

and I navigate from fragment to fragment using this

navController.navigate(FirstFragmentDirections.actionFirstFragmentToSecondFragment())

here is the code in the nav_graph

<fragment
    android:id="@+id/FirstFragment"
    android:name="com.example.app.presentation.ui.FirstFragment"
    android:label="FirstFragment" >
    <action
        android:id="@+id/action_FirstFragment_to_secondFragment"
        app:destination="@id/secondFragment"
        app:enterAnim="@anim/enter_from_right"
        app:exitAnim="@anim/exit_to_left"
        app:popEnterAnim="@anim/enter_from_left"
        app:popExitAnim="@anim/exit_to_right"
        />
</fragment>
<fragment
    android:id="@+id/secondFragment"
    android:name="com.example.app.presentation.ui.secondFragment"
    android:label="secondFragment"
    tools:layout="@layout/fragment_second" />

any help is appreciated thank you

Jankowski

Answer 1

You should generally never need to call setGraph() yourself, but you can workaround it like so in this particular case (and it will actually still work as you expect, because NavController / Navigator restores state properly across config changes and process death automatically):

if (savedInstanceState == null) {
    navController.setGraph(R.navigation.nav_graph,intent.extras)
}

Basuto

thank you I tried it and it fixed things. so setting the graph in onCreate is what was making it reset. thank you very much – Jankowski

Whats this intent.extras? what are we passing in it – Lisk

The arguments passed to the initial destination, I think – Basuto

Hi @EpicPandaForce, I too am having the issue of the navigation graph being reset when I resume my application (single activity app). Where do I need to place the above code in order to resolve this? – Seessel

@Seessel i would need to see more of your code as to how you initialize your NavHostFragment and your graph in your Activity or Fragment, I recommend opening a new question and then posting a comment here with your link, I will look at it. Normally you don't need to programatically set the graph, but if you do, it's Activity.onCreate or even Fragment.onCreate (using onCreateView causes bugs, so you'd have to add the NavhostFragment in onCreate too, very hacky, I have an example for it somewhere). – Basuto

@Basuto thank you for your reply I did open a new question here #72196730 – Seessel