DynamicNavHostFragment cause IllegalStateException in 2.6.0-alpha05 [268360479]

Fixed

Bug

Status Update

No update yet.

Description

da...@gmail.com

created issue #1

Feb 9, 2023 02:36AM

Using DynamicNavHostFragment in androidx.navigation:*:2.6.0-alpha05 cause an IllegalStateException when navigating.

Stacktrace:

FATAL EXCEPTION: main Process: com.geekorum.rdv.bwemanje.debug, PID: 10981 java.lang.IllegalStateException: You cannot access the Navigator's state until the Navigator is attached at androidx.navigation.Navigator.getState(Navigator.kt:68) at androidx.navigation.fragment.FragmentNavigator.access$getState(FragmentNavigator.kt:53) at androidx.navigation.fragment.FragmentNavigator$1.onBackStackChangeCommitted(FragmentNavigator.kt:81) at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:1954) at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1841) at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1778) at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:565) at android.os.Handler.handleCallback(Handler.java:942) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loopOnce(Looper.java:201) at android.os.Looper.loop(Looper.java:288) at android.app.ActivityThread.main(ActivityThread.java:7872) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)

This is caused by registering an OnBackStackChangeListener when constructing FragmentNavigator.

DynamicNavHostFragment first create a regular FragmentNavigator that registers his OnBackStackChangeListener. This navigator is then replaced by a DynamicFragmentNavigator. When the graph is created the navigators are all attached except the replaced FragmentNavigator which cause the crash as its OnBackStackChangeListener is still called.

To reproduce use the following layout in an activity and cause a navigation

        <androidx.fragment.app.FragmentContainerView
            android:id="@+id/nav_host_fragment"
            android:name="androidx.navigation.dynamicfeatures.fragment.DynamicNavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:defaultNavHost="true"
            app:navGraph="@navigation/mobile_navigation" />

Comments

il...@google.com <il...@google.com> Feb 9, 2023 04:37PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #2Feb 15, 2023 08:43PM

Oh I forgot to mention that I thought it might be connected to this issue: https://issuetracker.google.com/issues/243778589. But after trying 2.5.2 I can say that the issue persists.

jb...@google.com <jb...@google.com> #3Feb 15, 2023 09:35PM

Marked as fixed.

Please provide a minimal sample project along with the minimal steps to recreate the issue in the project.

na...@google.com <na...@google.com> #4Feb 22, 2023 07:10PM

Sorry for the delay. I got a working example here: https://github.com/Del-S/issues. The project is set up to crash when navigating to ThirdFragment (nested nav graph) with poping the graph.

I poked into it a little bit and it seems to be connected to SafeArgs gradle plugin. When safe args is used to navigate to ThirdFragment (with nested graph poped) it will try to recreate te parent but there were no arguments passed so it crashes.

Steps to reproduce:

Navigate from Second Fragment to Child nav graph (with non-nullable parameters).
Navigate to Third fragment using SafeArgs and the app crashes.

Crash log:

Process: cz.dels.issues, PID: 1743
java.lang.NullPointerException: null cannot be cast to non-null type kotlin.Long
at androidx.navigation.NavType$Companion$LongType$1.get(NavType.kt:352)
at androidx.navigation.NavType$Companion$LongType$1.get(NavType.kt:342)
at androidx.navigation.NavArgument.verify(NavArgument.kt:76)
at androidx.navigation.NavDestination.addInDefaultArgs(NavDestination.kt:502)
at androidx.navigation.NavController.addEntryToBackStack(NavController.kt:1865)
at androidx.navigation.NavController.addEntryToBackStack$default(NavController.kt:1813)
at androidx.navigation.NavController$navigate$4.invoke(NavController.kt:1721)
at androidx.navigation.NavController$navigate$4.invoke(NavController.kt:1719)
at androidx.navigation.NavController$NavControllerNavigatorState.push(NavController.kt:287)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:246)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.kt:162)
at androidx.navigation.NavController.navigateInternal(NavController.kt:260)
at androidx.navigation.NavController.navigate(NavController.kt:1719)
at androidx.navigation.NavController.navigate(NavController.kt:1545)
at androidx.navigation.NavController.navigate(NavController.kt:1472)
at androidx.navigation.NavController.navigate(NavController.kt:1930)
at cz.dels.issues.SecondFragment.onViewCreated$lambda-0(SecondFragment.kt:38)
at cz.dels.issues.SecondFragment.$r8$lambda$XDYnOS_cYrafiNQ5rcCu1WCn0IE(Unknown Source:0)
at cz.dels.issues.SecondFragment$$ExternalSyntheticLambda0.onClick(Unknown Source:2)

Note: If in step 2 SaveArgs is not used then navigation works correctly. More information is here: https://github.com/Del-S/issues/blob/master/app/src/main/java/cz/dels/issues/SecondFragment.kt#L37.

Issue 268360479

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Comments

il...@google.com <il...@google.com> Feb 9, 2023 04:37PM

ap...@google.com <ap...@google.com> #2Feb 15, 2023 08:43PM

jb...@google.com <jb...@google.com> #3Feb 15, 2023 09:35PM

na...@google.com <na...@google.com> #4Feb 22, 2023 07:10PM

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