How to assign values from array to buttons in Swift

Question

Hi I'm a beginner in Swift and I would like to know how I can make string values, stored in an array, the title of buttons.

Specific to my case: I have 24 buttons in my storyboard, all put into one action in the controller view. In my model I have an array with 24 emoji's and I would like to know how I can (randomly) assign these emoji's to my buttons.

var emoji : [String] = ["","", "","", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "","", "", "", "", ""]

Thank you in advance.

You could [shuffle the `emoji` array](http://stackoverflow.com/questions/24026510/how-do-i-shuffle-an-array-in-swift), and thereafter sequentially set the label of the `i`:th button to the `i`:th entry in the `emoji` array, for `i` ranging over your 24 buttons. — dfrib, Mar 31 '17 at 21:02
Fun fact, GameKit has a built in array shuffle function `let shuffledEmoji = GKRandomSource.sharedRandom().arrayByShufflingObjects(in: emoji)` which could help with this. — , Mar 31 '17 at 21:48

score 1 · Answer 1 · edited May 23 '17 at 11:46

When connecting the buttons to the code, connect them as an Outlet Connection. Then you will have an array of buttons. To set the button text accordingly:

for button in buttons {
    button.setTitle(emoji[buttons.index(of: button)!], for: [])
}

This will loop through all the buttons and set their title to the corresponding emojis. You can look at how to shuffle an array to randomize the emoji: How do I shuffle an array in Swift?

score 0 · Answer 2 · answered Mar 31 '17 at 22:40

Assuming you've added buttons to a view e.g. via interface builder you can do something like this. There are a lot of examples on how to sort the emoji array elsewhere.

class ViewController: UIViewController {

    let emoji = ["","", "","", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "","", "", "", "", ""]

    override func viewDidLoad() {
        super.viewDidLoad()
        let buttons: [UIButton] = view.subviews.flatMap { $0 as? UIButton }
        guard buttons.count <= emoji.count else {
            fatalError("Not enough emoji for buttons")
        }
        // sort emoji here
        _ = buttons.enumerated().map {  (index, element) in
            element.setTitle(emoji[index], for: .normal)
        }
    }
}

score 0 · Answer 3 · edited May 23 '17 at 12:02

This solution leverages shuffled() and zip()

class MyViewController: UIViewController {

    // Add the face buttons to the collection in the storyboard
    @IBOutlet var faceButtons: [UIButton]!
    let faces = ["","", "","", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "","", "", "", "", ""]

    func randomizeFaces() {
        // zip() combines faceButtons and faces, shuffled() randomizes faces
        zip(faceButtons, faces.shuffled()).forEach { faceButtton, face in
            faceButtton.setTitle(face, for: .normal)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        randomizeFaces()
    }

}

Here is the definition of shuffled() from: How do I shuffle an array in Swift?

extension MutableCollection where Indices.Iterator.Element == Index {
    /// Shuffles the contents of this collection.
    mutating func shuffle() {
        let c = count
        guard c > 1 else { return }

        for (firstUnshuffled , unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
            let d: IndexDistance = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
            guard d != 0 else { continue }
            let i = index(firstUnshuffled, offsetBy: d)
            swap(&self[firstUnshuffled], &self[i])
        }
    }
}

extension Sequence {
    /// Returns an array with the contents of this sequence, shuffled.
    func shuffled() -> [Iterator.Element] {
        var result = Array(self)
        result.shuffle()
        return result
    }
}

How to assign values from array to buttons in Swift

3 Answers3