SwiftUI doesn't like switch? - swift

Question

Trying to following this discussion, I implemented the suggestion of Yurii Kotov:
struct ContentView: View {
#State private var index = 0
#ViewBuilder
var body: some View {
if index == 0 {
MainView()
} else {
LoginView()
}
}
It works fine. But if I try to use a switch statement instead:
switch index {
case 0: MainView()
case 1: LoginView()
default:
print("# error in switch")
}
nothing happens. There is no mistake alert, but also no result at all. Could somebody help?

Answer 1

I had an issue with the default case where I wanted a "break" type situation for the switch to be exhaustive. SwiftUI requires some type of view, I found that
EmptyView() solved the issue.
also noted here EmptyView Discussion that you "have to return something"
struct FigureListMenuItems: View {
var showContextType: ShowContextEnum
#Binding var isFavoriteSeries: Bool?
var body: some View {
Menu {
switch showContextType {
case .series:
Button(action: { toggleFavoriteSeries() }) {
isFavoriteSeries! ?
Label("Favorite Series?", systemImage: "star.fill")
.foregroundColor(.yellow)
:
Label("Favorite Series?", systemImage: "star")
.foregroundColor(.yellow)
}
default: // <-- can use EmptyView() in this default too if you want
Button(action: {}) {
Text("No menu items")
}
}
} label: {
switch showContextType {
case .series:
isFavoriteSeries! ?
Image(systemName: "star.fill")
.foregroundColor(.yellow)
:
Image(systemName: "star")
.foregroundColor(.yellow)
default:
EmptyView()
}
Label("Menu", systemImage: "ellipsis.circle")
}
}
private func toggleFavoriteSeries() {
isFavoriteSeries?.toggle()
}
}
Enum for switch
enum ShowContextEnum: Int {
case series = 1
case whatIsNew = 2
case allFigures = 3
}

Answer 2

As #Sweeper said: your if...else and switch...case statements are not equal. The main idea is: body is just a computed variable of a View protocol and it should return something of its' type. Sure, you can do it with switch...case statements. In your code snippet mistake is in default statement: body cannot return() -> Void, only some View. So your code should looks like this:
struct ViewWithSwitchStatements: View {
#State var option = 0
var body: some View {
switch option {
case 1:
return AnyView(Text("Option 1"))
case 2:
return AnyView(Text("Option 2"))
default:
return AnyView(Text("Wrong option!"))
}
}
}
However you can't put it into VStack or something else, like if...else statements.