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iOS Swift 2.0 Enumerations and Optionals Introduction to Enumerations Enum Methods

Posted by Abdijabar Mohamed
Abdijabar Mohamed
1,462 Points

What is missing here?

Please help me debug this: To the button enum, add a method named toUIBarButtonItem that returns an instance of UIBarButton item configured properly.

In the buttons.swift file there is a basic implementation of UIBarButtonItem. You can create buttons with three different styles and titles.

Using the associated values as titles for the button, return a button with style UIBarButtonStyle.Done for the Done member of the Button 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 doneButton.

buttons.swift 
import Foundation

enum UIBarButtonStyle {
    case Done
    case Plain
    case Bordered
}

class UIBarButtonItem {

    var title: String?
    let style: UIBarButtonStyle
    var target: AnyObject?
    var action: Selector

    init(title: String?, style: UIBarButtonStyle, target: AnyObject?, action: Selector) {
        self.title = title
        self.style = style
        self.target = target
        self.action = action
    }
}
enums.swift 
enum Button {
    case Done(String)
    case Edit(String)

func toUIBarButtonItem() -> UIBarButton {
switch self {
case Button.Done: UIBarButtonItem(title: String?, style: UIBarButtonStyle.Done, target: nil, action: nil)
case Button.Edit: UIBarButtonItem(title: String?,style: UIBarButtonStyle.Done, target: nil, action: nil)

}
}
}
let done = Button.Done("Done")
let doneButton = done.toUIBarButtonItem()

1 Answer

Marina Alenskaja
Marina Alenskaja
9,320 Points
Marina Alenskaja
Marina Alenskaja
9,320 Points

Hi

You have to remember to pass in the associated values of the enum members - they request a string value. Therefore, using (let title) and then using the constant in the instance solves the challenge. 

enum Button {
   case Done(String)
   case Edit(String)


   func toUIBarButtonItem() -> 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 = Button.Done("Done")
 let doneButton = done.toUIBarButtonItem()

I had a lot of trouble with this challenge too!

I hope that helps :-)

Dan Hickey
Dan Hickey
3,016 Points
Dan Hickey
Dan Hickey
3,016 Points

I am not sure why this will not pass the challenge:

enum BarButton { case Done(title: String) case Edit(title: String)

func button() -> UIBarButtonItem { switch self { case .Done(let doneValue): return UIBarButtonItem( title: doneValue, style: .done, target: nil, action: nil) case .Edit(let editValue): return UIBarButtonItem( title: editValue, style: .plain, target: nil, action: nil) } } } let done = BarButton.Done(title: "Save") let button = done.button()