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iOS

Posted by Jonathan Halbrook
Jonathan Halbrook
3,853 Points

Can't figure out Enum Methods Challenge task 2

Can't figure out what I'm doing wrong. Challenge 2

"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."

link to challenge https://teamtreehouse.com/library/enumerations-and-optionals-in-swift-3/introduction-to-enumerations/enum-methods

Here's my code. It won't compile but seems to work on playground : 

enum Button {
    case done(String)
    case edit(String)

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

let done = Button.done("Save")

let button = done.button()

2 Answers

Philipp Munzert
Philipp Munzert
11,793 Points

I got it to work when I switched inside the method from "let value" to "let title" and also changed the variables in the returns:

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

        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)
            }

        }
    }

    let done = BarButton.done(title: "Save")
    let doneButton = done.button()
Jonathan Halbrook
Jonathan Halbrook
3,853 Points

That works! thanks!!

Phil Jones
Phil Jones
13,727 Points

Hello Phillipp, I took your code and changed one thing on the last line from: "let doneButton = done.button()" to: "let button = done.button()" It passed. :)

Matthew Connolly
seal-mask
.a{fill-rule:evenodd;}techdegree
Matthew Connolly
iOS Development Techdegree Student 11,595 Points
Matthew Connolly
.a{fill-rule:evenodd;}techdegree
Matthew Connolly
iOS Development Techdegree Student 11,595 Points

Hi Jonathan,

The challenge you link to is for "Enumerations and Optionals in Swift 3" and has some different syntax (see below) from Swift 2.

  • The Swift 3 Challenge changes the enum title: enum Button becomes enum BarButton
  • Also, because this is Swift 3 you need to include the argument label when you make an instance of BarButton.done
  • Make those tweaks, and your code should compile and pass in Treehouse
  • Also, you do not need to include UIBarButtonItemStyle when creating your button inside your button() method, you are okay to just write .done and .plain 
enum BarButton {
    case done(title: String)
    case edit(title: String)
}

let done = BarButton.done(title: "Save")
Jonathan Halbrook
Jonathan Halbrook
3,853 Points

Thanks so much! However when I make these changes the compiler say: Bummer! Make sure you assign to button the result of calling button(). Do not create an instance of UIBarButtonItem and assign it directly. I thought that is what I was doing??

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

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

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

let button = done.button()