ViewModel onCleared not called in Compose Navigation when Screen is rotated while navigation Back [298164648]

Fixed

Bug

Status Update

No update yet.

Description

to...@chefkoch.de

created issue #1

Aug 30, 2023 12:53PM

Component used: Navigation

Version used:

navigation-compose:2.7.1
hilt-navigation-compose:1.0.0
compose 1.5.0

If this is a bug in the library, we would appreciate if you could attach:

Sample project to trigger the issue -> https://github.com/TobyEb/NavigationOrientationChange

Issue:

Hi, I just encountered a weird behaviour which can be reproduced every time. My setup looks like this, Single Activity with Compose Navigation, some screens are locked to portrait orientation, some can be used in every orientation, e.g. to display images or videos.

Orientation is set like this while navigating:

class DestinationChangedListenerForOrientation : NavController.OnDestinationChangedListener {
        @SuppressLint("SourceLockedOrientationActivity")
        override fun onDestinationChanged(controller: NavController, destination: NavDestination, arguments: Bundle?) {
            requestedOrientation = if (destination.route == Screens.screenB) {
                ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED
            } else {
                ActivityInfo.SCREEN_ORIENTATION_PORTRAIT
            }
        }
    }

ScreenA is locked to portrait, ScreenB can be used in every orientation. If ScreenB is used in landscape mode, while navigating back an orientation change is requested which leads to activity recreation. I think because of the activity recreation ScreenBViewModel.onCleared is not called...

How to reproduce?

Start App
Navigate to ScreenB
Rotate your device to Landscape
Navigate back
Screen orientation changes and ScreenA is visible, ScreenBViewModel.onCleared is not called

You can just search the logs for "ScreenBViewModel", an info gets logged for init and onCleared of ScreenBViewModel. If ScreenB doesn't change its orientation onCleared is called as expected.

Expected behaviour:

For step 5 ScreenBViewModel.onCleared is called

Do you have any recommendations for a temporary workaround or any suggestions how orientation changes can be forced without losing the onCleared call?

Let me know if you need more info.

Best regards ✌️

Comments

il...@google.com <il...@google.com> Aug 30, 2023 04:58PM

Assigned to cl...@google.com.

cl...@google.com <cl...@google.com> #2Oct 6, 2023 02:09AM

Yigit, do you have time to fix it?

reemission of the same liveData is racy

ap...@google.com <ap...@google.com> #3Oct 10, 2023 11:04PM

yea i'll take it.

cl...@google.com <cl...@google.com> #4Oct 10, 2023 11:05PM

Marked as fixed.

Thanks for the detailed analysis. This may not be an issue anymore since we've started using Main.immediate there but I' not sure; I'll try to create a test case.

na...@google.com <na...@google.com> #5Nov 1, 2023 05:20PM

just emitting same live data reproduces the issue.

@Test
fun raceTest() {
val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData)
emitSource(subLiveData) //crashes
}
subject.addObserver().apply {
testScope.advanceUntilIdle()
}
}

na...@google.com <na...@google.com> #6Jan 24, 2024 07:53PM

With 2.2.0-alpha04 (that use Main.immediate), the issue seems to be still there (I tested it by calling emitSource() twice, like your test case)