Parameterized titles/labels for fragments using NavArgs and String id [167959935]

Fixed

Feature Request

androidx-bug-bounty

androidx-ui-starter-projects

Status Update

No update yet.

Description

co...@gmail.com

created issue #1

Sep 7, 2020 03:57PM

In order navigate using "NavDirection" directly created from a ViewModel would it be possible to pass R.string.id as argument?

Imagine a case where multiple errors leads you to a fragment that differs only by its text. Same behavior inside but only information change sightly. You would try to re-use that common part and avoid duplication.

If you try to generate a direction from your ViewModel with argument you won't be able to retrieve context assosiated string to fill the label. So would it be possible to parse a dynamic label's id instead of applying a toString() on it?

Currently if I send a NavDirection with an argument in it which is also {label} it will just apply a toString() and show id in place of toolbar title. Expected is the localised string as title to not resolve it using getString by myself (in a fragment, before or after navigation)

Sample project to trigger the issue.

   // snippet from nav_graph.xml
   <fragment
        android:id="@+id/FailureWithTitle"
        android:name="com.example.MyFragment"
        android:label="{title}" >
        <argument
            android:name="title"
            app:type="resource" />
   </fragment>
   <fragment
        android:id="@+id/firstFragemnt"
        android:name="com.example.MyFirstFragment"
        android:label="title" >
        <action 
               android:id="@+id/navigateToFailureWithTitle"
               ansdroid:destination= "@id/failureWithTitle"
        />
   </fragment>

   // snippet from strings.xml
   <string name="failure_invalid_request">Failure</string>
   <string name="failure_timeout">Timeout</string>
   <string name="failure_not_found">Not Found</string>

Some snippets from the way I would otherwise do it.

// viewModel
val navigateTo = MutableLiveData<NavDirection>()

private fun navigate() {
  when(case) {
   case0 -> navigateTo.post(MyFragmentAction.navigateToSuccess())
   case1 -> navigateTo.post(MyFragmentAction.navigateToFailureWithTitle(R.string.failure_invalid_request))
   case2 -> navigateTo.post(MyFragmentAction.navigateToFailureWithTitle(R.string.failure_timeout))
   case3 -> navigateTo.post(MyFragmentAction.navigateToFailureWithTitle(R.string.failure_not_found))
}

// Fragment
viewModel.navigateTo.observe(viewLifeCycleOwner, Observer { findNavController().navigateToDirection(it) } )

Current work around would be to create one destination per string_id reusing the same fragment "name" attribute and duplicate actions.

This would also remove the need of "getString()" logic from fragment or hook the "onDestinationChanged" as suggested some places just to update a title.

Screenshot_20200907-174905.jpg

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co...@gmail.com <co...@gmail.com> #2Sep 7, 2020 03:59PM

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.

il...@google.com <il...@google.com> Oct 5, 2021 09:25PM

Assigned to jb...@google.com.

jb...@google.com <jb...@google.com> Oct 6, 2021 04:49PM

Reassigned to sa...@google.com.

il...@google.com <il...@google.com> Jun 9, 2022 10:32PM

Reassigned to cl...@google.com.

cl...@google.com <cl...@google.com> Jun 14, 2022 05:54PM

Accepted by cl...@google.com.

ap...@google.com <ap...@google.com> #3Jun 17, 2022 12:41AM

Marked as fixed.

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

co...@gmail.com <co...@gmail.com> #4Jun 17, 2022 12:04PM

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.

cl...@google.com <cl...@google.com> #5Jun 17, 2022 05:08PM

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.

il...@google.com <il...@google.com> #6Jun 21, 2022 03:40PM

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