Question

我有一个带有几个按钮的UI。我想在单击按钮时导航到详细信息视图。第一次成功导航，但是当回到根视图并再次单击按钮时，我不导航。

我已经按照所有的教程进行了学习，可以看到与我所用的代码相同的代码，但是我没有发现发生了什么问题。

变量状态 @State var google: Int? = 0在视图类struct ContentView: View中已被定义

完整的根视图代码

struct ContentView: View {
@State var username: String = ""
@State var password: String = ""
@State var selection: Int? = nil
@State var google: Int? = 0
@State var buttton1: Int? = nil

var body: some View {
    NavigationView{
        VStack{
            Spacer()
            VStack (alignment: .center, spacing: 20){

                    Text("Quickly find and book a\n Doctors visit today")
                        .bold()
                        .font(.title)
                        .foregroundColor(.white)
                        .multilineTextAlignment(.center)

                    TextField("Email", text: $username)
                        .padding(.horizontal)
                        .foregroundColor(.white)
                        .accentColor(.white)

                    Divider()

                    TextField("Password", text: $password)
                         .padding(.horizontal)
                        .foregroundColor(.white)
                        .accentColor(.white)

                    Divider()

                    NavigationLink(destination: DetailView(), tag: 3, selection: self.$buttton1) {

                        EmptyView();
                    }

                    Button(action:{
                        self.buttton1 = 3;
                        print("Login");
                    }){

                        Text("Sign in")
                            .padding()
                            .frame(minWidth: 0, maxWidth: .infinity)
                            .background(Color.green)
                            .cornerRadius(3)
                            .foregroundColor(Color.white)
                    }

                    Text("Forgot password?")
                        .foregroundColor(Color.white)
            }
            .padding(20)

            HStack {
                VStack { Divider().background(Color.white) }
                Text("or")
                    .foregroundColor(Color.white)
                VStack { Divider().background(Color.white) }
            }
            .padding(20)

            VStack(alignment: .leading, spacing: 20){
                    Button(action:{
                        print("Search and sign up user");
                    }){
                        Text("Search and sign up user")
                            .padding()
                            .frame(minWidth: 0, maxWidth: .infinity)
                            .foregroundColor(Color.white)
                            .border(Color.white, width: 1)
                            .cornerRadius(3)
                    }

                NavigationLink(destination: DetailView(), tag: 2, selection: self.$google) {
                    Button(action:{
                        self.google = 2;
                        print("Sign in with Google");
                    }){
                        HStack {
                            /*Image(systemName: "")
                                .font(.title)*/
                            Text("Sign in with Google")
                                .padding()
                                .frame(minWidth: 0, maxWidth: .infinity)
                                .foregroundColor(Color.black)
                                .background(Color.white)
                                .cornerRadius(3)
                        }
                    }
                }



                /*NavigationLink(
                    destination: DetailView()){

                        Text("Click Me")
                        .frame(minWidth: 0, maxWidth: .infinity)
                        .background(Color.black)
                        .foregroundColor(Color.white)
                    }*/

                NavigationLink(destination: DetailView(), tag: 1, selection: $selection) {

                    //EmptyView()
                    Button(action:{
                                //self.tag = 1;
                        self.selection = 1;
                                print("Sign in with Apple");

                            },label: {
                                Text("Sign in with Apple")
                            })
                            .frame(minWidth: 0, maxWidth: .infinity,minHeight: 50, maxHeight: 50)
                            .background(Color.black)
                            .cornerRadius(3)
                            .foregroundColor(Color.white)
                            }
                }
                .padding(20)

            }
            .background(Color.blue)
            .edgesIgnoringSafeArea(.all)
    }
}
}

struct ContentView: View {
@State var username: String = ""
@State var password: String = ""
@State var selection: Int? = nil
@State var google: Int? = 0
@State var buttton1: Int? = nil

var body: some View {
    NavigationView{
        VStack{
            Spacer()
            VStack (alignment: .center, spacing: 20){

                    Text("Quickly find and book a\n Doctors visit today")
                        .bold()
                        .font(.title)
                        .foregroundColor(.white)
                        .multilineTextAlignment(.center)

                    TextField("Email", text: $username)
                        .padding(.horizontal)
                        .foregroundColor(.white)
                        .accentColor(.white)

                    Divider()

                    TextField("Password", text: $password)
                         .padding(.horizontal)
                        .foregroundColor(.white)
                        .accentColor(.white)

                    Divider()

                    NavigationLink(destination: DetailView(), tag: 3, selection: self.$buttton1) {

                        EmptyView();
                    }

                    Button(action:{
                        self.buttton1 = 3;
                        print("Login");
                    }){

                        Text("Sign in")
                            .padding()
                            .frame(minWidth: 0, maxWidth: .infinity)
                            .background(Color.green)
                            .cornerRadius(3)
                            .foregroundColor(Color.white)
                    }

                    Text("Forgot password?")
                        .foregroundColor(Color.white)
            }
            .padding(20)

            HStack {
                VStack { Divider().background(Color.white) }
                Text("or")
                    .foregroundColor(Color.white)
                VStack { Divider().background(Color.white) }
            }
            .padding(20)

            VStack(alignment: .leading, spacing: 20){
                    Button(action:{
                        print("Search and sign up user");
                    }){
                        Text("Search and sign up user")
                            .padding()
                            .frame(minWidth: 0, maxWidth: .infinity)
                            .foregroundColor(Color.white)
                            .border(Color.white, width: 1)
                            .cornerRadius(3)
                    }

                NavigationLink(destination: DetailView(), tag: 2, selection: self.$google) {
                    Button(action:{
                        self.google = 2;
                        print("Sign in with Google");
                    }){
                        HStack {
                            /*Image(systemName: "")
                                .font(.title)*/
                            Text("Sign in with Google")
                                .padding()
                                .frame(minWidth: 0, maxWidth: .infinity)
                                .foregroundColor(Color.black)
                                .background(Color.white)
                                .cornerRadius(3)
                        }
                    }
                }



                /*NavigationLink(
                    destination: DetailView()){

                        Text("Click Me")
                        .frame(minWidth: 0, maxWidth: .infinity)
                        .background(Color.black)
                        .foregroundColor(Color.white)
                    }*/

                NavigationLink(destination: DetailView(), tag: 1, selection: $selection) {

                    //EmptyView()
                    Button(action:{
                                //self.tag = 1;
                        self.selection = 1;
                                print("Sign in with Apple");

                            },label: {
                                Text("Sign in with Apple")
                            })
                            .frame(minWidth: 0, maxWidth: .infinity,minHeight: 50, maxHeight: 50)
                            .background(Color.black)
                            .cornerRadius(3)
                            .foregroundColor(Color.white)
                            }
                }
                .padding(20)

            }
            .background(Color.blue)
            .edgesIgnoringSafeArea(.all)
    }
}

}

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

Answer 1

带有SwiftUI的XCode和模拟器上的已知错误实际上在实际设备上可以正常运行。您不能在同一视图中连续两次按下

。

例如，假设您有3行（＃1，＃2，＃3），每行都有一个NavigationLink，则您将无法推动＃1，请再次返回并再次推动＃1。

如果您先运行＃1，＃2，然后再次运行＃1，则它会起作用。

同样，它只是在模拟器上。在真实的设备上尝试相同的代码，那会很好！

希望这会有所帮助！

更新：该错误已在XCode 11.4中修复。您现在可以多次导航到同一视图！苹果干得好;）

按钮单击导航到DetailView在SwiftUI中不起作用

1 个答案: