如何在UILabel上快速下划线？

您可以使用NSAttributedString做到这一点

例：

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

编辑

为了使一个UILabel的所有文本具有相同的属性，建议您将UILabel子类化并覆盖文本，如下所示：

斯威夫特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        }    }}

斯威夫特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        }    }}

然后将您的文本像这样：

@IBOutlet weak var label: UnderlinedLabel!    override func viewDidLoad() {        super.viewDidLoad()        label.text = "StringWithUnderLine"    }

旧：

迅捷（2.0到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        }    }}