Enum with switch in Swift

Question

I'm trying to loop over all tab items to set some properties through a switch using enum:

enum TabItems {
    case FirstTab
    case SecondTab
    case ThirdTab
}

Here's my loop:

for item in self.tabBar.items {
    switch item.tag {
    case .FirstTab:
        println("first tab")
    default:
        println("tab not exists")
    }
}

There is an error: Enum case 'FirstTab' not found in type 'Int!'. How do I properly use enum in this switch statement?

Answer 1

You're getting the error because item.tag is declared as an Int (NSInteger in the API originally) but you're trying to compare it to your TabItems enumeration. You can either use Int values in your switch statement:

for item in self.tabBar.items {
    switch item.tag {
    case 0:
        println("first tab")
    case 1:
        println("second tab")
    default:
        println("not recognized")
    }
}

Or you can convert the tag to your enum, like the example below. (Note that you'll need to update your enumeration's declaration to support .fromRaw().)

enum TabItems : Int {
    case FirstTab = 0
    case SecondTab
    case ThirdTab
}

for item in self.tabBar.items {
    if let tabItem = TabItems.fromRaw(item.tag) {
        switch tabItem {
        case .FirstTab:
            println("first tab")
        case .SecondTab:
            println("second tab")
        default:
            println("not recognized")
        }
    }
}