推,Segue,召唤,导航到以编程方式快速查看

我想做最简单的事情。我只想以编程方式调用一个新的SwiftUI视图-不是用按钮,而是用代码。我已经读过几十篇关于这个的文章和苹果文档——但我发现的几乎所有内容都与被重命名或弃用的代码有关。我发现最接近的是:

NavigationLink(destination: NewView(), isActive: $something) {
    EmptyView()
}

但在Xcode Beta 7中这对我不起作用。下面是一个简单的应用程序:

struct ContentView: View {
    @State private var show = false

    var body: some View {

        VStack {
            Text("This is the ContentView")

            Toggle(isOn: $show) {
                Text("Toggle var show")
            }
            .padding()

            Button(action: {
                self.show = !self.show
            }, label: {
                Text(self.show ? "Off" : "On")
            })
            Text(String(show))

            //this does not work - the ContentView is still shown
            NavigationLink(destination: SecondView(), isActive: $show)
            {
             EmptyView()
            }

            //this does not work - it adds SecondView to ContentView
            //I want a new view here, not an addition
            //to the ContentView()
//            if show {
//                //I want a new view here, not an addition to the ContentView()
//                SecondView()
//            }
        }
    }

}

还有一个极其简单的目的地:

struct SecondView: View {
    var body: some View {
        Text("this is the second view!")
    }
}

我一定错过了一些非常简单的东西。任何指导都将不胜感激。 iOS 13.1,卡特琳娜19A546d,Xcode 11M392r