Value updates not called within a coroutine scope on iOS

[azlekov]

@arkivanov this maybe is a bit tricky, but I'm trying to use coroutines making a network calls. I have a component with a state controlling the UI and a instance keeper following the samples. On Android everything works like a charm but on iOS my UI stuck on the initial UI state. The screen is updated if a navigate to another view and return back. Can you help here?

This is my common KMM decompose component

class HomesComponent(
    componentContext: DodiComponentContext,
    private val onNewHome: () -> Unit,
    private val onHomeDetails: (property: Property) -> Unit
) : Homes,
    DodiComponentContext by componentContext {

    private val scope = coroutineScope(Dispatchers.Main)
    private val homesRepository = HomesRepository(settings)
    private val handler = instanceKeeper.getOrCreate { Handler(Homes.UIState.Loading, scope, homesRepository) }

    override val state: Value<Homes.UIState>
        get() = handler.state

    override fun onNewHomeClicked() {
        onNewHome()
    }

    override fun onHomeDetailsClicked(property: Property) {
        onHomeDetails(property)
    }

    private class Handler(
        initialState: Homes.UIState,
        private val scope: CoroutineScope,
        private val homesRepository: HomesRepository
    ) : InstanceKeeper.Instance {
        val state: MutableValue<Homes.UIState> = MutableValue(initialState)

        init {
            scope.launch {
                state.value = Homes.UIState.Loading
                Logger.d("Loading")
                try {
                    val response = withContext(Dispatchers.Default) {
                        homesRepository.myHomes()
                    }

                    if (response.hasErrors()) {
                        Logger.e("Error")
                        state.value = Homes.UIState.Error
                        return@launch
                    }

                    if (response.data?.properties?.isEmpty() == true) {
                        Logger.d("HasNoData")
                        state.value = Homes.UIState.HasNoData
                    } else {
                        Logger.d("HasData(size = ${response.dataAssertNoErrors.properties.size})")
                        state.value = Homes.UIState.HasData(response.dataAssertNoErrors.properties.map { it.property })
                    }
                } catch (ex: Exception) {
                    state.value = Homes.UIState.Error
                }
            }
        }

        override fun onDestroy() {
            scope.cancel()
        }
    }
}

Even with a simpler suspend code is not working, I have tried also with:

private class Handler(
        initialState: Homes.UIState,
        private val scope: CoroutineScope,
    ) : InstanceKeeper.Instance {
        val state: MutableValue<Homes.UIState> = MutableValue(initialState)

        init {
            scope.launch {
                state.value = Homes.UIState.Loading
                Logger.d("Loading")
                delay(2000)
                state.value = Homes.UIState.Error
            }
        }

        override fun onDestroy() {
            scope.cancel()
        }
    }

Here is my Swift UI:

struct HomesView: View {
    
    private var component: Homes
    private var state: HomesUIState { component.state.value }
    
    init(_ component: Homes) {
        self.component = component
    }
    
    var body: some View {
        let _ = debugPrint(state)
        switch state {
        case is HomesUIState.Loading:
            VStack {
                Spacer()
                ProgressView().progressViewStyle(.circular).padding()
                Spacer()
            }
        case is HomesUIState.HasNoData:
            VStack {
                Spacer()
                EmptyPlaceholderView(image: "calendar-white-icon", title: "Add a property first", text: "You need to add a property before you can start accepting bookings", action: {component.onNewHomeClicked()}, actionIcon: "add-icon")
                Spacer()
            }
        case is HomesUIState.Error:
            VStack {
                Spacer()
                EmptyPlaceholderView(image: "calendar-white-icon", title: "Add a property first", text: "You need to add a property before you can start accepting bookings", action: {component.onNewHomeClicked()}, actionIcon: "add-icon")
                Spacer()
            }.toastView(toast: Binding.constant(Toast(message: "Error fetching properties")))
        default:
            EmptyView()
        }
    }
}

I'm seeing Loading on the log and that's it, nothing further. Android is working with both cases. Any ideas?

[arkivanov]

I think this is because SwiftUI doesn't observe Value. I updated the docs recently, you can try using ObservableValue.

[azlekov]

I will check and come back here, but looking at my code snippet the coroutines setup should be working, right?