state.swift

struct MyView: View {
    @State var text: String = "hello"
    var body: some View {
        TextField("title", text: $text)
    }
}

struct ContentView: View {
    @State var toggled: Bool = false
    var body: some View {
        let theTextView = MyView()
        return VStack {
            Toggle(isOn: $toggled, label: { Text("Toggle") })
            if toggled {
                theTextView
            } else {
                theTextView.accentColor(.green)
            }
        }
    }
}