How to retrieve ViewModel using viewModel(...) whose ViewModelStore is Activity itself of Activity scoped?

Question

Jetnews demo application uses this code for retrieving ViewModel https://github.com/android/compose-samples/blob/main/JetNews/app/src/main/java/com/example/jetnews/ui/JetnewsNavGraph.kt :

    composable(JetnewsDestinations.INTERESTS_ROUTE) {
        val interestsViewModel: InterestsViewModel = viewModel(
            factory = InterestsViewModel.provideFactory(appContainer.interestsRepository)
        )
        InterestsRoute(
            interestsViewModel = interestsViewModel,
            isExpandedScreen = isExpandedScreen,
            openDrawer = openDrawer
        )
    }

viewModel has documentation for the viewModelStoreOwner:

viewModelStoreOwner: ViewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current)

viewModelStoreOwner - The owner of the ViewModel that controls the scope and lifetime of the returned ViewModel. Defaults to using LocalViewModelStoreOwner.

https://stackoverflow.com/a/58893398/1375882 assures that both Fragment and Activity is ViewModelStore - implements relevenat capability.

My question is - how can I get access to the Activity as the ViewModelStore in the NavGraph composable(ROUTE) code block (which is @Composable apparently) and use is as viewModelStoreOwner argument for creating/retrieving activity-wide ViewModel instance? Is this possible at all? This block is part of @Composable and the reference to Activity my induce some leaks, isn't it?

score 0 · Answer 1 · answered Aug 09 '22 at 14:10

My experiments and tests show that the following works as expected:

composable(JetnewsDestinations.INTERESTS_ROUTE) {
        val interestsViewModel: InterestsViewModel = viewModel(
            viewModelStoreOwner = (LocalContext.current as AppCompatActivity),
            factory = InterestsViewModel.provideFactory(appContainer.interestsRepository)
        )
        InterestsRoute(
            interestsViewModel = interestsViewModel,
            isExpandedScreen = isExpandedScreen,
            openDrawer = openDrawer
        )
    }

My understanding is that AppCompatActivity I can use (my MainActivity is of this type, I have single-activity Jetpack Compose app), but I should be very, very cautious about getting the reference to it, as detailed in How to get activity in compose

How to retrieve ViewModel using viewModel(...) whose ViewModelStore is Activity itself of Activity scoped?

1 Answers1