Underline button text in Swift

Question

I have UIButton. In interface builder I set its title to be 'Attributed'. How can I make its title to be underlined from code in Swift?

@IBOutlet weak var myBtn: UIButton!

I created a function called on the touchUpInside event of this button:

var attributedString = NSMutableAttributedString(string:"new text")
    var attrs = [
        NSFontAttributeName : UIFont.systemFontOfSize(19.0),
        NSForegroundColorAttributeName : UIColor.redColor()
    ]
    var gString = NSMutableAttributedString(string:"g", attributes:attrs)
    attributedString.appendAttributedString(gString)

    myBtn.titleLabel?.attributedText = attributedString;

But still no result. Also I need to know how to access the underline attribute. Text, size and color stay the same.

Answer 1

Thanks for posting your code, it wasn't clear that you knew how to create an attributed string at all.

This should work:

var attrs = [
    NSFontAttributeName : UIFont.systemFontOfSize(19.0),
    NSForegroundColorAttributeName : UIColor.redColor(),
    NSUnderlineStyleAttributeName : NSUnderlineStyle.StyleSingle.rawValue
]

Swift 4 version:

var attrs : [NSAttributedStringKey : Any] = [
    NSAttributedStringKey.font : UIFont.systemFont(ofSize: 19.0),
    NSAttributedStringKey.foregroundColor : UIColor.red,
    NSAttributedStringKey.underlineStyle : NSUnderlineStyle.styleSingle.rawValue
]

Answer 2

Here you go, just tested it. (works in xCode 7 Beta at least)

@IBOutlet weak var yourButton: UIButton!

var attrs = [
NSFontAttributeName : UIFont.systemFontOfSize(19.0),
NSForegroundColorAttributeName : UIColor.redColor(),
NSUnderlineStyleAttributeName : 1]

var attributedString = NSMutableAttributedString(string:"")

override func viewDidLoad() {
  super.viewDidLoad()

  let buttonTitleStr = NSMutableAttributedString(string:"My Button", attributes:attrs)
  attributedString.appendAttributedString(buttonTitleStr)
  yourButton.setAttributedTitle(attributedString, forState: .Normal)
}

Answer 3

if you are looking for a way to do this without inheritance -

swift 3/4/5

// in swift 4 - switch NSUnderlineStyleAttributeName with NSAttributedStringKey.underlineStyle

extension UIButton {
    func underline() {
        guard let text = self.titleLabel?.text else { return }
        let attributedString = NSMutableAttributedString(string: text)
        //NSAttributedStringKey.foregroundColor : UIColor.blue
        attributedString.addAttribute(NSAttributedString.Key.underlineColor, value: self.titleColor(for: .normal)!, range: NSRange(location: 0, length: text.count))
        attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: self.titleColor(for: .normal)!, range: NSRange(location: 0, length: text.count))
        attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSRange(location: 0, length: text.count))
        self.setAttributedTitle(attributedString, for: .normal)
    }
}



extension UILabel {
    func underline() {
        if let textString = self.text {
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSRange(location: 0, length: attributedString.length - 1))
            attributedText = attributedString
        }
    }
}

Answer 4

StoryBoard: If you want to Underline text from storyBoard.

• Select button or label title as Attributed.
• Select range of text which you want to underline.
• Right click and choose Font then select underline.

Answer 5

Swift 5 / Xcode 11

  @IBOutlet weak var myButton: UIButton!

  let yourAttributes: [NSAttributedString.Key: Any] = [
      .font: UIFont.systemFont(ofSize: 14),
      .foregroundColor: UIColor.blue,
      .underlineStyle: NSUnderlineStyle.single.rawValue]
         //.double.rawValue, .thick.rawValue

  override func viewDidLoad() {
     super.viewDidLoad()

     let attributeString = NSMutableAttributedString(string: "Your button text",
                                                     attributes: yourAttributes)
     myButton.setAttributedTitle(attributeString, for: .normal)
  }

Swift 4 / Xcode 9

  @IBOutlet weak var myButton: UIButton!

  let yourAttributes : [NSAttributedStringKey: Any] = [
      NSAttributedStringKey.font : UIFont.systemFont(ofSize: 14),
      NSAttributedStringKey.foregroundColor : UIColor.blue,
      NSAttributedStringKey.underlineStyle : NSUnderlineStyle.styleSingle.rawValue]
         //.styleDouble.rawValue, .styleThick.rawValue, .styleNone.rawValue

  override func viewDidLoad() {
    super.viewDidLoad()

    let attributeString = NSMutableAttributedString(string: "Your button text",
                                                    attributes: yourAttributes)
    myButton.setAttributedTitle(attributeString, for: .normal)
  }

Swift 3 / Xcode 8

  @IBOutlet weak var myButton: UIButton!

  let yourAttributes : [String: Any] = [
      NSFontAttributeName : UIFont.systemFont(ofSize: 14),
      NSForegroundColorAttributeName : UIColor.white,
      NSUnderlineStyleAttributeName : NSUnderlineStyle.styleSingle.rawValue] 
         //.styleDouble.rawValue, .styleThick.rawValue, .styleNone.rawValue

   override func viewDidLoad() {
      super.viewDidLoad()

      let attributeString = NSMutableAttributedString(string: "Your button text", 
                                                       attributes: yourAttributes)        
      myButton.setAttributedTitle(attributeString, for: .normal) 
    }

Answer 6

@ShlomoKoppel answer in Swift 4.2

extension UIButton {
    func underline() {
        guard let text = self.titleLabel?.text else { return }
        let attributedString = NSMutableAttributedString(string: text)
        //NSAttributedStringKey.foregroundColor : UIColor.blue
        attributedString.addAttribute(NSAttributedString.Key.underlineColor, value: self.titleColor(for: .normal)!, range: NSRange(location: 0, length: text.count))
        attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: self.titleColor(for: .normal)!, range: NSRange(location: 0, length: text.count))
        attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSRange(location: 0, length: text.count))
        self.setAttributedTitle(attributedString, for: .normal)
    }
}



extension UILabel {
    func underlineMyText() {
        if let textString = self.text {
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSRange(location: 0, length: attributedString.length - 1))
            attributedText = attributedString
        }
    }
}