Comment souligner un UILabel dans swift?

Vous pouvez faire cela en utilisant NSAttributedString

Exemple:

let underlineAttribute = [NSUnderlineStyleAttributeName: NSUnderlineStyle.StyleSingle.rawValue]
let underlineAttributedString = NSAttributedString(string: "StringWithUnderLine", attributes: underlineAttribute)
myLabel.attributedText = underlineAttributedString

MODIFIER

D'avoir les mêmes attributs pour tous les textes d'un UILabel, je vous suggère de faire une sous-classe UILabel et en remplaçant le texte, comme ça:

Swift 4.2

class UnderlinedLabel: UILabel {

override var text: String? {
    didSet {
        guard let text = text else { return }
        let textRange = NSMakeRange(0, text.count)
        let attributedText = NSMutableAttributedString(string: text)
        attributedText.addAttribute(NSAttributedString.Key.underlineStyle , value: NSUnderlineStyle.single.rawValue, range: textRange)
        //Add other attributes if needed
        self.attributedText = attributedText
        }
    }
}

Swift 3.0

class UnderlinedLabel: UILabel {

    override var text: String? {
        didSet {
            guard let text = text else { return }
            let textRange = NSMakeRange(0, text.characters.count)
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName , value: NSUnderlineStyle.styleSingle.rawValue, range: textRange)
            //Add other attributes if needed
            self.attributedText = attributedText
        }
    }
}

Et vous mettez votre texte comme ceci :

@IBOutlet weak var label: UnderlinedLabel!

    override func viewDidLoad() {
        super.viewDidLoad()

        label.text = "StringWithUnderLine"
    }

VIEUX:

Swift (2.0 à 2.3):

class UnderlinedLabel: UILabel {

    override var text: String? {
        didSet {
            guard let text = text else { return }
            let textRange = NSMakeRange(0, text.characters.count)
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName, value:NSUnderlineStyle.StyleSingle.rawValue, range: textRange)
            //Add other attributes if needed

            self.attributedText = attributedText
        }
    }
}

Swift 1.2:

class UnderlinedLabel: UILabel {

    override var text: String! {
        didSet {
            let textRange = NSMakeRange(0, count(text))
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName, value:NSUnderlineStyle.StyleSingle.rawValue, range: textRange)
            //Add other attributes if needed

            self.attributedText = attributedText
        }
    }
}

si vous êtes à la recherche d'un moyen de le faire sans l'héritage -

swift 3/4

//in swift 4 - switch NSUnderlineStyleAttributeName with NSAttributedStringKey.underlineStyle
extension UILabel {
    func underline() {
        if let textString = self.text {
          let attributedString = NSMutableAttributedString(string: textString)
          attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSRange(location: 0, length: attributedString.length - 1))
          attributedText = attributedString
        }
    }
}


extension UIButton {
  func underline() {
    let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
    attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSRange(location: 0, length: (self.titleLabel?.text!.characters.count)!))
    self.setAttributedTitle(attributedString, for: .normal)
  }
}

Vous pouvez souligner la UILabel texte à l'aide de Interface Builder.

Voici le lien de ma réponse : L'ajout d'attribut de soulignement de texte partiel UILabel dans le storyboard

Swift 4 changements.
N'oubliez pas d'utiliser NSUnderlineStyle.styleSingle.rawValue au lieu de NSUnderlineStyle.styleSingle.

   'let attributedString = NSAttributedString(string: "Testing")
    let textRange = NSMakeRange(0, attributedString.length)
    let underlinedMessage = NSMutableAttributedString(attributedString: attributedString)
    underlinedMessage.addAttribute(NSAttributedStringKey.underlineStyle,
                                   value:NSUnderlineStyle.styleSingle.rawValue,
                                   range: textRange)
    label.attributedText = underlinedMessage

`

La réponse ci-dessus est à l'origine d'une erreur dans mon environnement de construction.

Cela ne fonctionne pas dans Swift 4.0:

attributedText.addAttribute(NSUnderlineStyleAttributeName, 
                            value: NSUnderlineStyle.styleSingle.rawValue, 
                            range: textRange)

Essayez plutôt ceci:

attributedText.addAttribute(NSAttributedStringKey.underlineStyle,
                            value: NSUnderlineStyle.styleSingle.rawValue,
                            range: textRange)

espère que cela aide quelqu'un.

Souligner à plusieurs chaînes de caractères dans une phrase.

extension UILabel {
    func underlineMyText(range1:String, range2:String) {
        if let textString = self.text {

            let str = NSString(string: textString)
            let firstRange = str.range(of: range1)
            let secRange = str.range(of: range2)
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: firstRange)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: secRange)
            attributedText = attributedString
        }
    }
}

Utiliser de cette manière.

    lbl.text = "By continuing you agree to our Terms of Service and Privacy Policy."
    lbl.underlineMyText(range1: "Terms of Service", range2: "Privacy Policy.")

Vous pouvez l'utiliser aussi, si vous voulez atteindre la moitié seulement de la partie de l'étiquette comme le soulignent:- //Swift 4.0+

let attributesForUnderLine: [NSAttributedString.Key: Any] = [
            .font: UIFont(name: AppFont.sourceSansPro_Regular, size: 12) ?? UIFont.systemFont(ofSize: 11),
            .foregroundColor: UIColor.blue,
            .underlineStyle: NSUnderlineStyle.single.rawValue]

        let attributesForNormalText: [NSAttributedString.Key: Any] = [
            .font: UIFont(name: AppFont.sourceSansPro_Regular, size: 12) ?? UIFont.systemFont(ofSize: 11),
            .foregroundColor: AppColors.ColorText_787878]

        let textToSet = "Want to change your preferences? Edit Now"
        let rangeOfUnderLine = (textToSet as NSString).range(of: "Edit Now")
        let rangeOfNormalText = (textToSet as NSString).range(of: "Want to change your preferences?")

        let attributedText = NSMutableAttributedString(string: textToSet)
        attributedText.addAttributes(attributesForUnderLine, range: rangeOfUnderLine)
        attributedText.addAttributes(attributesForNormalText, range: rangeOfNormalText)
        yourLabel.attributedText = attributedText