Hi! I’m using navigation-compose alpha06 and having crashes whenever I tried to popBackStack from a ...

# compose

[Tin Tran]

Hi! I’m using navigation-compose alpha06 and having crashes whenever I tried to popBackStack from a nested navigation.
Does anyone having the same issue?
Sample code in 🧵

[Tin Tran]

sample.kt

[Tin Tran]

The error is because this line

hiltViewModel(navController.getBackStackEntry("b")

[Tin Tran]

Whenever I tried to popBackStack from nestedB got this error

java.lang.IllegalArgumentException: No destination with route b is on the NavController's back stack. The current destination is Destination(0xe5901274) route=a

[Tin Tran]

Issue created
https://issuetracker.google.com/issues/195570271

[Ian Lake]

Sounds like the same issue as https://kotlinlang.slack.com/archives/CJLTWPH7S/p1628012256418100?thread_ts=1628012256.418100&cid=CJLTWPH7S where you aren't taking into consideration that the animations between destinations mean you're going to recompose multiple times even after you are popped (for the fade exit animations)

[Ian Lake]

Have you tried wrapping your call to getBackStackEntry() in a remember?

[Tin Tran]

Not yet. I’ll try it

[Tin Tran]

I tried this but no luck

navigation(startDestination = "nestedB", route = "b") {
                        composable(route = "nestedB") {
                            val backStackEntry = remember {navController.getBackStackEntry("b")}
                            ComposableB(navController = navController, hiltViewModel(backStackEntry))
                        }
                        composable(route = "nestedC") {
                            val backStackEntry = remember {navController.getBackStackEntry("b")}
                            ComposableC(navController = navController, hiltViewModel(backStackEntry))
                        }
                    }

[Tin Tran]

it throws

java.lang.IllegalStateException: You cannot access the NavBackStackEntry's ViewModels until it is added to the NavController's back stack (i.e., the Lifecycle of the NavBackStackEntry reaches the CREATED state).

[Ian Lake]

Ah, I missed that you were accessing the nested graph, that'd be the same issue as this thread: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1626962860278800?thread_ts=1626960240.270300&cid=CJLTWPH7S

[Ian Lake]

Which resulted in this issue which we're tracking: https://issuetracker.google.com/issues/194313238

[Tin Tran]

Oh! Thank you! I’ll will comment on the duplicated issue of mine.