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@tfcporciuncula
Last active April 23, 2024 13:29
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Getting arg from ViewModel with savedStateHandle
// Both screens look the same, but now we have a ViewModel and some differences on the App composable
@HiltViewModel
class DetailsViewModel @Inject constructor(
savedStateHandle: SavedStateHandle,
) : ViewModel() {
private val state = MutableStateFlow(requireNotNull(savedStateHandle.get("arg")))
fun state() = state.asStateFlow()
}
@Composable
fun App(
modifier: Modifier = Modifier,
) {
Box(
modifier = modifier
.fillMaxSize()
.background(color = colorScheme.background),
) {
val navController = rememberNavController()
NavHost(navController = navController, startDestination = "start") {
composable(route = "start") {
StartScreen(
onNavigateClick = { arg -> navController.navigate(route = "details/$arg") },
)
}
// ---> interesting changes are here <---
composable(route = "details/{arg}") { navBackStackEntry ->
val arg = requireNotNull(navBackStackEntry.arguments?.getString("arg"))
navBackStackEntry.savedStateHandle.set("arg", arg)
val viewModel = hiltViewModel<DetailsViewModel>()
val state by viewModel.state().collectAsStateWithLifecycle(lifecycleOwner = navBackStackEntry)
DetailsScreen(arg = state.arg)
}
}
}
}
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