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iOS Enumerations and Optionals in Swift Introduction to Enumerations Enum Methods

Joan Perez Lozano
PLUS
Joan Perez Lozano
Courses Plus Student 3,190 Points

What is missing here?

Next, add a method to the enum named button that returns an instance of the class UIBarButtonItem configured properly. An example of how to create an instance for this task is shown in the comments below. Use the same initializer.

In the method, using the associated values as titles for the button, return a button with style UIBarButtonStyle.done for the done member of the BarButton enum. Similarly for the edit member, return a UIBarButtonItem instance with the style set to UIBarButtonStyle.plain.

In both cases you can pass nil for target and action. Once you have a method, call it on the value we created in the previous task and assign it to a constant named button.

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 {
      let someButton = UIBarButtonItem(title: "A Title", style: .plain, target: nil, action: nil)
      switch self {
       case .done: return UIBarButtonStyle.done
       case .edit: return UIBarButtonItem.plain
      }
    }

}



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

1 Answer

David Papandrew
David Papandrew
8,386 Points

A couple of items to fix:

1) The someButton constant should be declared outside the enum code block

2) You need to tweak the method so that a UIBarButtonItem with all the necessary parameters is returned

Here's the corrected code:

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

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

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