Unable to navigate to a new instance of the same Fragment type after Jetpack Navigation 2.4.x update [237374580]

Fixed

Bug

Status Update

No update yet.

Description

ho...@gmail.com

created issue #1

Jun 28, 2022 01:57PM

Artifact used (ex. androidx.appcompat:appcompat:1.0.0-alpha1): androidx.navigation:navigation-ui-ktx, androidx.navigation:navigation-fragment-ktx

Version used: 2.4.2 Theme used: Devices/Android versions reproduced on: Pixel XL emulator / API 30

Relevant code to trigger the issue. https://github.com/rahobbs/NavExperiments

I'm updating Jetpack Navigation from 2.3.4 to 2.4.2 and believe I have found a breaking change in my project.

Let's say I have a MainFragment and a SecondFragment. Launching SecondFragment from MainFragment (with safeArgs) works as expected. However, I also need to be able to launch a new instance of SecondFragment from SecondFragment with new arguments. I'm constructing a new navigation action and telling the navController to navigate to it. Before updating, I could see that this navigation action was taken, and I hit onCreateView and other lifecycle methods in my SecondFragment class.

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    val button = view.findViewById<Button>(R.id.myButton)

    button.setOnClickListener {
        val action = SecondFragmentDirections.newSecondFragment("coming from second")
        Log.d("SecondFragment", "click ${action.arguments.get("myArg")}")
        findNavController().navigate(action)
    }

    val text = view.findViewById<TextView>(R.id.message)
    text.text = safeArgs.myArg
}

Now with the update, my log statement there is being logged and is correct, but it seems like the navigation action never happens, as I'm never hitting onCreateView or onViewCreated, and my SecondFragment does not update with the new arguments.

I have a small reproducible example here: https://github.com/rahobbs/NavExperiments/tree/main/app/src/main/java/com/example/navexperiments

Comments

st...@gmail.com <st...@gmail.com> #2Jul 7, 2022 12:24PM

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.

ow...@google.com <ow...@google.com> #3Jul 8, 2022 10:49AM

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

il...@google.com <il...@google.com> Jul 13, 2022 11:49PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #4Aug 24, 2022 12:04AM

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.

jb...@google.com <jb...@google.com> #5Aug 24, 2022 12:14AM

Marked as fixed.

Ups a typo: Navigate from ~~Second~~ First Fragment to Child nav graph (with non-nullable parameters).

Note: sorry for the spam but I am not able to edit my own comment.

l....@gmail.com <l....@gmail.com> #6Aug 24, 2022 09:01PM

This has been fixed and will be available in navigation 2.6.0-alpha08

na...@google.com <na...@google.com> #7Sep 12, 2022 05:52PM

Project: platform/frameworks/support
Branch: androidx-main

commit 6b358154b794a0456b089ac8e548bfb830dd6c22
Author: Clara Fok <clarafok@google.com>
Date: Tue Mar 14 17:56:12 2023

Fix missing non-nullable arg when rebuilding hierarchy

When navigating with NavDirections, args is populated with an empty bundle. This causes issue when we rebuild parent hierarchy while adding a new entry to NavBackStack. If the Entry being rebuilt contains a non-nullalbe arg, i.e. Long, this empty bundle will cause an exception.

Test: ./gradlew navigation:navigation-runtime:cC
Bug: 249988437
Change-Id: I5c8ce739ad9a3428c8a8de13eae391bfff0db5df

M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt

https://android-review.googlesource.com/2488855

am...@gmail.com <am...@gmail.com> #8Dec 9, 2022 10:43PM

The following release(s) address this bug.It is possible this bug has only been partially addressed:

androidx.navigation:navigation-runtime:2.6.0-alpha08

am...@gmail.com <am...@gmail.com> #9Dec 9, 2022 10:44PM

even after using app:launchSingleTop="false" new instance of fragment is not created