SwiftUI 使用按钮更改视图 [英] SwiftUI Change View with Button

问题描述

我知道有 PresentationButton 和 NavigationButton 是为了在最新的 SwiftUI 中更改视图.但是我想做一个简单的操作，如下所示.当用户单击登录"按钮时，如果凭据正确，它将登录并执行 segue(在这种情况下更改视图).但是，我无法在 PresentationButton 中检查它们是否正确，也无法更改普通按钮中的视图.还有其他方法吗?

I understand there is PresentationButton and NavigationButton in order to change views in the latest SwiftUI. However I want to do a simple operation like below. When user clicks on SignIn button if credentials are correct it will sign them in but also do a segue (in this case change the view). However I could not check if they are correct in PresentationButton and I could not change the view in a normal button. Is there another way to do that?

  @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
        }




    }

推荐答案

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.")
        }
    }
}

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