SwiftUI—如何切换部分表单项目的可见性

struct ContentView : View {
    @State var showingVisible = false //用来标识是否隐藏表单
    @State var userName = ""
    @State var password = ""
    var body: some View {
        NavigationView {
            Form {
                Toggle(isOn: $showingVisible.animation()) { //使用该视图显示或隐藏表单
                    if(showingVisible){
                        Text("Hide Form")
                    }
                    else{
                        Text("Show Form")
                    }
                }
                if(showingVisible)
                {
                    Section(header: Text("Please enter your information:")) {
                        TextField("Username", text: $userName)
                        SecureField("Password", text: $password)
                    }
                }
            }.navigationBarTitle(Text("Profiles"))
        }
    }
}