Using switch/enums in SwiftUI Views - swiftui

Question

As of Xcode 11.4, SwiftUI doesn't allow switch statements in Function builder blocks like VStack {}, failing with a generic error like Generic parameter 'Content' could not be inferred. How can the switch statement be used in SwiftUI to create different Views depending on an enum value?

Answer 1

switch in SwiftUI view builders is supported since Xcode 12:
enum Status {
case loggedIn, loggedOut, expired
}
struct SwiftUISwitchView: View {
#State var userStatus: Status = .loggedIn
var body: some View {
VStack {
switch self.userStatus {
case .loggedIn:
Text("Welcome!")
case .loggedOut:
Image(systemName: "person.fill")
case .expired:
Text("Session expired")
}
}
}
}

Answer 2

You can use enum with #ViewBuilder as follow ...
Declear enum
enum Destination: CaseIterable, Identifiable {
case restaurants
case profile
var id: String { return title }
var title: String {
switch self {
case .restaurants: return "Restaurants"
case .profile: return "Profile"
}
}
}
Now in the View file
struct ContentView: View {
#State private var selectedDestination: Destination? = .restaurants
var body: some View {
NavigationView {
view(for: selectedDestination)
}
}
#ViewBuilder
func view(for destination: Destination?) -> some View {
switch destination {
case .some(.restaurants):
CategoriesView()
case .some(.profile):
ProfileView()
default:
EmptyView()
}
}
}
If you want to use the same case with the NavigationLink ... You can use it as follow
struct ContentView: View {
#State private var selectedDestination: Destination? = .restaurants
var body: some View {
NavigationView {
List(Destination.allCases,
selection: $selectedDestination) { item in
NavigationLink(destination: view(for: selectedDestination),
tag: item,
selection: $selectedDestination) {
Text(item.title).tag(item)
}
}
}
}
#ViewBuilder
func view(for destination: Destination?) -> some View {
switch destination {
case .some(.restaurants):
CategoriesView()
case .some(.profile):
ProfileView()
default:
EmptyView()
}
}
}