SwiftUI Alert shown once-CodePudding

My app consumes few API endpoints to fetch data, that is managed by respective ViewModels.

For example, this ViewModel fetch the languages

class LanguageViewModel: ObservableObject {
    var subscriptions: Set<AnyCancellable> = []

    @Published private(set) var languages: [LanguageItem]?
    @Published private(set) var error: Error?

    func get() {
        APIService.fetchData()
            .receive(on: DispatchQueue.main)
            .sink(receiveCompletion: { [weak self] value in
                guard let self = self else { return }
                if case let .failure(error) = value {
                    self.error = error
                }

            }, receiveValue: { (data: [LanguageItem]) in
                self.languages = data

            })
            .store(in: &self.subscriptions)
    }
}

and so on.

Now for the main UI

struct ContentView: View {
    @ObservedObject private var languageViewModel = LanguageViewModel()

    var body: some View {
        let hasError = Binding<Bool>(
            get: { self.languageViewModel.error != nil },
            set: { _ in }
        )

        Button(action: {
            self.languageViewModel.get()
        }) {
            Text("Hello, World")
        }
        .alert(isPresented: hasError) {
            let message = self.languageViewModel.error?.description

            return Alert(title: Text("Error"), message: Text(message ?? ""), dismissButton: .default(Text("OK")))
        }
    }
}

If somehow the API call fails on clicking the button, the first and only first time the alert is shown, then on subsequent clicks does not appear.

Placing a breakpoint on .alert show that the code is running correctly, just not showing again.

Please send help!!

CodePudding user response：

On alert dismiss button action reset error back to nil, like:

.alert(isPresented: hasError) {
    let message = self.languageViewModel.error?.description

    return Alert(title: Text("Error"), message: Text(message ?? ""), dismissButton: .default(Text("OK")) {
       self.languageViewModel.error = nil    // << here !!
    })
}