SwiftUI 使用按钮更改视图

Question

我知道有PresentationButton 和NavigationButton 以便在最新的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，但也会执行 segue（在这种情况下更改视图）。但是我无法检查它们在PresentationButton 中是否正确，也无法在普通按钮中更改视图。

还有其他方法吗？

  @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.")
        }
    }
}

Answer 2

我的一个应用也有同样的需求，我找到了解决方案...

基本上你需要在 NavigationView 中插入你的主视图，然后在你的视图中添加一个不可见的 NavigationLink，创建一个 @state 变量来控制你何时想要推送视图并在你的登录回调中更改它的值...

代码如下：

struct ContentView: View {
    @State var showView = false
    var body: some View {
        NavigationView {
            VStack {
                Button(action: {
                    print("*** Login in progress... ***")
                    DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
                        self.showView = true
                    }
                }) {
                    Text("Push me and go on")
                }

                //MARK: - NAVIGATION LINKS
                NavigationLink(destination: PushedView(), isActive: $showView) {
                    EmptyView()
                }
            }
        }
    }
}


struct PushedView: View {
    var body: some View {
        Text("This is your pushed view...")
            .font(.largeTitle)
            .fontWeight(.heavy)
    }
}

Answer 3

尝试使用 state & .sheet

struct ContentView: View {
    @State var showingDetail = false

    var body: some View {
        Button(action: {
            self.showingDetail.toggle()
        }) {
            Text("Show Detail")
        }.sheet(isPresented: $showingDetail) {
            DetailView()
        }
    }
}

Answer 4

您可以使用带有标签的导航链接，

代码如下：

首先，声明标签变量

@State var tag : Int? = nil

然后创建你的按钮视图：

Button("Log In", action: {
                        Auth.auth().signIn(withEmail: self.email, password: self.password, completion: { (user, error) in
                            if error == nil {
                                self.tag = 1
                                print("success")
                            }else{
                                print(error!.localizedDescription)
                            }
                        })

所以当登录成功标签将变为 1 时，当标签变为 1 时，您的导航链接将被执行

导航链接代码：

NavigationLink(destination: HomeView(), tag: 1, selection: $tag) {
                EmptyView()
                }.disabled(true)

如果您使用的是表单，请使用 .disabled，因为此处的空视图将在表单上可见，并且您不希望您的用户单击它并转到 homeView。