Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Enumerations and Optionals in Swift Introduction to Enumerations Enum Methods

Jonatan Witoszek
Jonatan Witoszek
15,384 Points

Use of unresolved identifier - compilation error

When I try to submit the code I get ¨use of unresolved identifier¨ compilatior error. What can be the cause of this?

Error log:

swift_lint.swift:52:55: error: use of unresolved identifier 'UIBarButtonStyle'
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.done, target: nil, action: nil)
                                                      ^~~~~~~~~~~~~~~~
swift_lint.swift:22:6: note: did you mean 'UIBarButtonItemStyle'?
enum UIBarButtonItemStyle : Int {
     ^
swift_lint.swift:27:7: note: did you mean 'UIBarButtonItem'?
class UIBarButtonItem {
      ^
swift_lint.swift:54:55: error: use of unresolved identifier 'UIBarButtonStyle'
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.plain, target: nil, action: nil)
                                                      ^~~~~~~~~~~~~~~~
swift_lint.swift:22:6: note: did you mean 'UIBarButtonItemStyle'?
enum UIBarButtonItemStyle : Int {
     ^
swift_lint.swift:27:7: note: did you mean 'UIBarButtonItem'?
class UIBarButtonItem {
      ^
buttons.swift
// Example of UIBarButtonItem instance
// let someButton = UIBarButtonItem(title: "A Title", style: .plain, target: nil, action: nil)

enum BarButton {
    case done(title: String)
    case edit(title: String)

    func button() -> UIBarButtonItem {
      switch self {
        case .done(let title):
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.done, target: nil, action: nil)
        case .edit(let title):
          return UIBarButtonItem(title: title, style: UIBarButtonStyle.plain, target: nil, action: nil)
      }
    }
}

let done = BarButton.done(title: "Save")
let button = done.button()

1 Answer

Hi Jonatan,

For the style just pass in .done or .plain without the preceding UIBarButtonStyle; like this:

    func button() -> UIBarButtonItem {
      switch self {
        case .done(let title):
          return UIBarButtonItem(title: title, style: .done, target: nil, action: nil)
        case .edit(let title):
          return UIBarButtonItem(title: title, style: .plain, target: nil, action: nil)
      }
    }    

That should work fine.

Steve.