I have tried to add an alert to the login button informing the user if they have entered an incorrect password. I added a showAlert.toggle to the signIn function but my syntax is wrong and XCode produces the following two errors:

1. "Value of tuple type '()' has no member 'alert'"

2. "Expected ',' separator"

Here is my ViewModel code:

 func badPassword() -> Alert {
    return Alert(title: Text("Incorrect password"))
}

func signIn(email: String, password: String) {
    
    Auth.auth().signIn(withEmail: email, password: password) { (authResult, error) in
        switch error {
        case .some(let error as NSError) where error.code == AuthErrorCode.wrongPassword.rawValue:
            showAlert.toggle()
                .alert(isPresented: $showAlert, content: {
                    badPassword()}
                    print("wrong password")
                case .some(let error):
                    print("Login error: \(error.localizedDescription)")
                case .none:
                    if let user = authResult?.user {
                        print(user.uid)
                        DispatchQueue.main.async {
                            self.signedIn = true
                        }
                    }
                }
                       }
                       }
                       }

Here is my View code:

struct SignInView: View {
@State var email = ""
@State var password = ""
@State var wrongPassword = false
@State var showAlert: Bool = false
@EnvironmentObject var viewModel: AppViewModel

var body: some View {
    ZStack {
        VStack {
            Spacer()
            HStack {
                Image(systemName: "mail")
                    .foregroundColor(.gray)
                TextField("Email Address", text: $email)
                    .disableAutocorrection(true)
                    .autocapitalization(.none)
                    .padding()
            }
            .frame(width: 325, height: 50)
            .background(Color.black.opacity(0.05))
            .cornerRadius(10)
            
            
            HStack {
                Image(systemName: "lock")
                    .foregroundColor(.gray)
                SecureField("Password", text: $password)
                    .disableAutocorrection(true)
                    .autocapitalization(.none)
                    .padding()
            }
            .frame(width: 325, height: 50)
            .background(Color.black.opacity(0.05))
            .cornerRadius(10)
            Button(action: {
                guard !email.isEmpty, !password.isEmpty else {
                    return
                }
                viewModel.signIn(email: email, password: password)
                }, label: {
                Text("Sign In")
                    .frame(width: 200, height: 50)
                    .background(Color.blue)
                    .cornerRadius(8)
                    .foregroundColor(Color.white)

CodePudding user response：

You can use Alert like this in SwiftUI:

struct ContentView: View {
 
  @StateObject var vm = ViewModel()

  var body: some View {
    
       ZStack {
         
        }.alert(isPresented: $vm.showError, content: {
                Alert(title: Text(vm.errorMessage))
            })
     }
}

And your ViewModel class:

class ViewModel: ObservableObject {
    
    @Published var showError = false
    var errorMessage = ""

   func showError(message: String) {
        errorMessage = message
        showError = true
    }

}

You can use showError(message: String) anywhere to show error. In your case:

switch error {
        case .some(let error as NSError) where error.code == AuthErrorCode.wrongPassword.rawValue:
            
        showError(message: "Wrong Password")
        
        ...
 }