swift - SwiftUI用按钮更改 View

Question

我了解有PresentationButton和NavigationButton以便在最新的SwiftUI中更改 View 。但是我想做一个简单的操作，如下所示。如果凭据正确无误，当用户单击“登录”按钮时，它将登录它们，但还会进行排序(在这种情况下，请更改 View )。但是，我无法在PresentationButton中检查它们是否正确，也无法在普通按钮中更改 View 。还有另一种方法吗？

  @IBAction func signInClicked(_ sender: Any) {

        if emailText.text != "" && passwordText.text != "" {

            Auth.auth().signIn(withEmail: emailText.text!, password: passwordText.text!) { (userdata, error) in
                if error != nil {
                   //error
                } else {

                   performSegue(withIdentifier: "toFeedActivity", sender: nil)


                }
            }

        } else {
            //error
        }




    }

Answer 1

这是一种方法。

struct AppContentView: View {
    
    @State var signInSuccess = false
    
    var body: some View {
        return Group {
            if signInSuccess {
                AppHome()
            }
            else {
                LoginFormView(signInSuccess: $signInSuccess)
            }
        }
    }
}

struct LoginFormView : View {
    
    @State private var userName: String = ""
    @State private var password: String = ""
    
    @State private var showError = false
    
    @Binding var signInSuccess: Bool
    
    var body: some View {
        VStack {
            HStack {
                Text("User name")
                TextField("type here", text: $userName)
            }.padding()
            
            HStack {
                Text(" Password")
                TextField("type here", text: $password)
                    .textContentType(.password)
            }.padding()
            
            Button(action: {
                // Your auth logic
                if(self.userName == self.password) {
                    self.signInSuccess = true
                }
                else {
                    self.showError = true
                }
                
            }) {
                Text("Sign in")
            }
            
            if showError {
                Text("Incorrect username/password").foregroundColor(Color.red)
            }
        }
    }
}

struct AppHome: View {
    
    var body: some View {
        VStack {
        Text("Hello freaky world!")
        Text("You are signed in.")
        }
    }
}