ios - SwiftUI切换 View

Question

我对Swift还是很陌生，我向php脚本创建了一个小的POST请求，该请求发布了用户输入的数据并返回了JSON响应。但是现在我正在为某些事情而苦苦挣扎。在我的动作脚本中，按钮代表打印错误或打印json响应。
但是现在我想更改它，以便转到HomeView。

我试图将HomeView（）放入if语句中，但是它不起作用。

希望您能够帮助我。

import SwiftUI

struct AppRootView: View {

    @State var signedIn: Bool = false

    var body: some View {

        Group{
            if(signedIn){
                HomeView()
            } else {
                Login()
            }
        }
    }

}

struct ContentView: View {
    var body: some View {


        Login()

    }
}


struct HomeView: View {
    var body: some View {
    Text("test")
    }
}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}



struct Login : View {

    @State var user = ""
    @State var pass = ""

    @Binding var signedIn: Bool


    var body : some View {



        VStack{

            /*Group {
                       if (signedIn) {
                           HomeView()
                       } else {
                           Login()
                       }
                   }*/

            Image("logo")
                .resizable()
                .frame(width: 100, height: 100)

            Text("Sign In").fontWeight(.heavy).font(.largeTitle).foregroundColor(Color("Iso-Blue")).padding([.top,.bottom], 20)

            VStack(alignment: .leading){

                VStack(alignment: .leading){

                    Text("Username").font(.headline).fontWeight(.light)

                    HStack{

                        TextField("Enter Your Username", text: $user)


                    }

                    Divider()

                }

                VStack(alignment: .leading){

                    Text("Password").font(.headline).fontWeight(.light)


                        SecureField("Enter Your Password", text: $pass)

                        Divider()

                }




            }.padding(.horizontal, 6)

             VStack{

                /*if (signedIn == true) {
                    HomeView()
                } else {
                    Login()
                }*/

                 Button(action: {

                             let url = URL(string: "http://192.168.178.39/iso/loginserv.php")
                             guard let requestUrl = url else { fatalError() }

                             var request = URLRequest(url: requestUrl)
                             request.httpMethod = "POST"

                            let postString = "user=\(self.user)&pass=\(self.pass)";

                             request.httpBody = postString.data(using: String.Encoding.utf8);

                             let task = URLSession.shared.dataTask(with: request) {
                                 (data, response, error) in

                                 if let error = error {
                                     print("Error took place \(error)")
                                     return
                                 }

                                if let data = data, let dataString = String(data: data, encoding: .utf8) {
                                     print("Response data string:\n \(dataString)")
                                     self.signedIn = true


                                }

                    }

                task.resume()



                }) {
                     Text("Sign In").foregroundColor(.white).frame(width: UIScreen.main.bounds.width - 120).padding()

                 }.background(Color("Iso-Gray"))
                 .clipShape(Capsule())
                 .padding(.top, 45)
             }

        }.padding()  

    }
}

Answer 1

为了适应swiftui的声明性，这需要一些重新思考和重写。问题是登录结构不够高。登录之前，我们需要告诉框架有关HomeView的信息。

在UIKit应用中；我们将要求用户登录，然后在成功登录后选择进入HomeView。

在SwiftUI应用中；我们声明一个RootView根据当前状态显示正确的视图。

struct AppRootView: View {

  @State var signedIn: Bool = false

  var body: some View {

    Group {
      if (signedIn) {
        HomeView()
      } else {
        LoginView(signedIn: $signedIn)
      }
    }

  }
}

接下来，将绑定添加到您在上面链接的loginView上。注意，我将绑定作为参数传递给loginView。

struct LoginView: View {

  @Binding var signedIn: Bool

  ...

  if let data = data, let dataString = String(data: data, encoding: .utf8) {
    print("Response data string:\n \(dataString)")
    signedIn = true
  }

  ...

}