如何在 Swift 中为UILabel 加下划线？我搜索了 Objective-C 的，但无法让它们在 Swift 中工作。
【问题讨论】：
NSAttributedString?
标签： ios swift overriding uilabel nsattributedstring
您可以使用NSAttributedString 来做到这一点
例子：
let underlineAttribute = [NSAttributedString.Key.underlineStyle: NSUnderlineStyle.thick.rawValue]
let underlineAttributedString = NSAttributedString(string: "StringWithUnderLine", attributes: underlineAttribute)
myLabel.attributedText = underlineAttributedString
编辑
要使一个 UILabel 的所有文本具有相同的属性，我建议您将 UILabel 子类化并覆盖文本，如下所示：
斯威夫特 5
与 Swift 4.2 相同，但：您应该更喜欢 Swift 初始化程序 NSRange 而不是旧的 NSMakeRange，您可以缩短为 .underlineStyle 并且换行符提高了长方法调用的可读性。 p>
class UnderlinedLabel: UILabel {
override var text: String? {
didSet {
guard let text = text else { return }
let textRange = NSRange(location: 0, length: text.count)
let attributedText = NSMutableAttributedString(string: text)
attributedText.addAttribute(.underlineStyle,
value: NSUnderlineStyle.single.rawValue,
range: textRange)
// Add other attributes if needed
self.attributedText = attributedText
}
}
}
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
}
}
}
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
}
}
}
你把你的文字写成这样：
@IBOutlet weak var label: UnderlinedLabel!
override func viewDidLoad() {
super.viewDidLoad()
label.text = "StringWithUnderLine"
}
旧：
Swift（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
}
}
}
【讨论】：
NSRange 时，您应该传递 UTF16 计数而不是字符计数
required init?(coder: NSCoder) { super.init(coder: coder) self.addUnderline() // your code }
我有在我的应用程序中使用的算法。在这个算法中，即使单词之间有空格，您也可以在子字符串下划线
extension NSMutableAttributedString{
static func findSubStringAndUnderlineIt(subStringToBeFound : String,totalString : String)-> NSMutableAttributedString?{
let attributedString = NSMutableAttributedString(string: totalString)
var spaceCount = 0
if subStringToBeFound.contains(" "){
spaceCount = subStringToBeFound.components(separatedBy:" ").count-1
}
if let range = attributedString.string.range(of: subStringToBeFound, options: .caseInsensitive){
attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSMakeRange((range.lowerBound.utf16Offset(in: subStringToBeFound)) ,(range.upperBound.utf16Offset(in: subStringToBeFound)) +
spaceCount))
return attributedString
}
return attributedString
}
}
在使用过的部分
lblWarning.attributedText = NSMutableAttributedString.findSubStringAndUnderlineIt(subStringToBeFound:"Not: Sadece uygulamanın reklamları kaldırılacaktır.", totalString: lblWarning.text!)
【讨论】：
extension String {
var underLined: NSAttributedString {
NSMutableAttributedString(string: self, attributes: [.underlineStyle: NSUnderlineStyle.single.rawValue])
}
}
打开按钮：
button.setAttributedTitle(yourButtonTitle.underLined, for: .normal)
在标签上：
label.attributedText = yourLabelTitle.underLined
【讨论】：
如果您正在寻找一种无需继承的方法：
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))
attributedText = attributedString
}
}
}
// 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))
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)
}
}
【讨论】：
NSRange 时，您应该传递UTF16 计数而不是字符计数
一个用于为 Swift 5 的 UIbuttons 设置和删除下划线的类。我希望这会有所帮助
import Foundation
import UIKit
class UiUtil {
static let underlineThickness = 2
class func removeUnderlineFromButton( _ button:UIButton ) {
if let str = button.titleLabel?.attributedText {
let attributedString = NSMutableAttributedString( attributedString: str )
attributedString.removeAttribute(.underlineStyle, range:
NSRange.init(location: 0, length: attributedString.length))
button.setAttributedTitle(attributedString, for: .normal)
}
}
class func setUnderlineFromButton( _ button:UIButton ) {
if let str = button.titleLabel?.attributedText {
let attributedStringUnderline = NSMutableAttributedString( attributedString:
str )
attributedStringUnderline.addAttribute(
NSAttributedString.Key.underlineStyle,
value: underlineThickness,
range: NSRange.init(location: 0, length: attributedStringUnderline.length)
)
button.setAttributedTitle(attributedStringUnderline, for: .normal)
}
}
}
【讨论】：
Swift 4、4.2 和 5。
@IBOutlet weak var lblUnderLine: UILabel!
我需要在 UILabel 中为特定文本添加下划线。所以，找到范围并设置属性。
let strSignup = "Don't have account? SIGNUP NOW."
let rangeSignUp = NSString(string: strSignup).range(of: "SIGNUP NOW.", options: String.CompareOptions.caseInsensitive)
let rangeFull = NSString(string: strSignup).range(of: strSignup, options: String.CompareOptions.caseInsensitive)
let attrStr = NSMutableAttributedString.init(string:strSignup)
attrStr.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.white,
NSAttributedString.Key.font : UIFont.init(name: "Helvetica", size: 17)! as Any],range: rangeFull)
attrStr.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.white,
NSAttributedString.Key.font : UIFont.init(name: "Helvetica", size: 20)!,
NSAttributedString.Key.underlineStyle: NSUnderlineStyle.thick.rawValue as Any],range: rangeSignUp) // for swift 4 -> Change thick to styleThick
lblUnderLine.attributedText = attrStr
输出
【讨论】：
如果你只想将标签的一半作为下划线，你也可以使用它：- //对于 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
【讨论】：
Swift 5 & 4.2 一个班轮：
label.attributedText = NSAttributedString(string: "Text", attributes:
[.underlineStyle: NSUnderlineStyle.single.rawValue])
Swift 4 一个班轮：
label.attributedText = NSAttributedString(string: "Text", attributes:
[.underlineStyle: NSUnderlineStyle.styleSingle.rawValue])
Swift 3 一班轮：
label.attributedText = NSAttributedString(string: "Text", attributes:
[NSUnderlineStyleAttributeName: NSUnderlineStyle.styleSingle.rawValue])
【讨论】：
为一个句子中的多个字符串加下划线。
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
}
}
}
以这种方式使用。
lbl.text = "By continuing you agree to our Terms of Service and Privacy Policy."
lbl.underlineMyText(range1: "Terms of Service", range2: "Privacy Policy.")
【讨论】：
Swift 4.2
中的相同答案对于UILable
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: textString.count))
self.attributedText = attributedString
}
}
}
如下调用UILabel
myLable.underline()
对于UIButton
extension UIButton {
func underline() {
if let textString = self.titleLabel?.text {
let attributedString = NSMutableAttributedString(string: textString)
attributedString.addAttribute(NSAttributedString.Key.underlineStyle,
value: NSUnderlineStyle.single.rawValue,
range: NSRange(location: 0, length: textString.count))
self.setAttributedTitle(attributedString, for: .normal)
}
}
}
如下调用UIButton
myButton.underline()
我查看了上述答案，其中一些是强制展开 text 值。我会建议通过安全展开来获得价值。这将避免在 nil 值的情况下崩溃。 希望这会有所帮助:)
【讨论】：
NSRange 时，您应该传递UTF16 计数而不是字符计数
对于 Swift 2.3
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, forState: .Normal)
}
}
在 ViewController 中
@IBOutlet var yourButton: UIButton!
在ViewDidLoad方法或者你的函数里写
yourButton.underline()
它会在你的按钮标题下划线
【讨论】：
// Swift 4 版本
let attributedString = NSMutableAttributedString(string: "Your Text Here", attributes: [NSAttributedStringKey.underlineStyle : true])
self.yourlabel.attributedText = attributedString
【讨论】：
对 Swift 4 和 Xcode 9 中的 Shlome 答案稍作修正。
extension UILabel {
func underline() {
if let textString = self.text {
let attributedString = NSMutableAttributedString(string: textString)
attributedString.addAttribute(NSAttributedStringKey.underlineStyle,
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(NSAttributedStringKey.underlineStyle,
value: NSUnderlineStyle.styleSingle.rawValue,
range: NSRange(location: 0, length: (self.titleLabel?.text!.count)!))
self.setAttributedTitle(attributedString, for: .normal)
}
}
【讨论】：
NSRange 时，您应该传递UTF16 计数而不是字符计数
上面的答案导致我的构建环境出错。
这在 Swift 4.0 中不起作用：
attributedText.addAttribute(NSUnderlineStyleAttributeName,
value: NSUnderlineStyle.styleSingle.rawValue,
range: textRange)
试试这个：
attributedText.addAttribute(NSAttributedStringKey.underlineStyle,
value: NSUnderlineStyle.styleSingle.rawValue,
range: textRange)
希望这对某人有所帮助。
【讨论】：
Swift 4 发生了变化。 请记住使用 NSUnderlineStyle.styleSingle.rawValue 而不是 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
`
【讨论】：
您可以使用 Interface Builder 为 UILabel 文本添加下划线。
这是我的答案的链接：Adding underline attribute to partial text UILabel in storyboard
【讨论】：