I expected that the

savedStateHandle

in my `ViewModel`:

@HiltViewModel
class MyViewModel @Inject constructor(
    savedStateHandle: SavedStateHandle,
)

was the same as the

savedStateHandle

from the

NavBackStackEntry

that was used as the

ViewModelStoreOwner

to create the `ViewModel`:

composable("route") {
    val viewModel: MyViewModel = hiltViewModel(
        remember { navController.getBackStackEntry("route") }
    )
    val savedStateHandle = navController.getBackStackEntry("route").savedStateHandle
    MyComposable(/* args */)
}

… but it’s not. Is there a way to accomplish this without having to update properties on the

ViewModel

after it’s been created?

All

navBackStackEntry.savedStateHandle

does is create its own ViewModel and get its SavedStateHandle: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:navigation/navigation-common/src/main/java/androidx/navigation/NavBackStackEntry.kt;l=117 so yeah, it'll be a different SavedStateHandle

You'd need to request exactly the same ViewModel (i.e., ask for a ChargeSessionsViewModel) if you want that exact ViewModel. That's certainly supported and means you don't need to go through SavedStateHandle at all

But at that point, maybe you should take a step back and think about if your initial request makes sense at all. If you're on your second screen and you go through process death and recreation, then that previous destinations ViewModel won't exist anymore - it'll be recreated when you access it. It will have its SavedStateHandle restored and maybe that's enough for your case?

But it really sounds like if you aren't processing your results in the destination itself, then maybe you shouldn't be returning a result at all and should instead have that second destination directly access what shared repository later that both ViewModels use as their single source of truth

I still think that the mechanism for communicating simple data between destinations is useful, but you end up having to handle that data in the UI. It would be nice to be able to handle that communication in the ViewModel.

For completeness, this is how I tried to work around that. It works, but it’s not very elegant:

composable("route") {
    val viewModel: MyViewModel = hiltViewModel()
    LaunchedEffect(viewModel, navController) {
        val savedStateHandle =
            navController.getBackStackEntry("route").savedStateHandle
        savedStateHandle
            .getLiveData<String?>("result")
            .asFlow()
            .filterNotNull()
            .collect {
                viewModel.onResult(it)
                savedStateHandle["result"] = null
            }
    }
    MyComposable(/* args */)
}