UILabel - 如何在Swift 3中添加行间距

Question

我有一个包含多行文本的UILabel，我想在每行之间添加一些空格，就像这张图片一样。

请帮我实现它。我已经尝试查阅苹果开发者关于标签和行距的所有文档，但没有找到相关内容。

- user7620770

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你尝试过什么？请发布可重现的代码以便他人帮助您。为了获得更好的回复，改进您的问题，请阅读http://stackoverflow.com/help/how-to-ask。 - Brian O'Donnell

感谢Brian O'Donnell的建议。我已经看到了。我是这个网站的新手，所以不知道问题回答模式已经完成。 - user7620770

Answer 1

从Interface Builder（故事板/XIB）：

通过编程实现：

Swift 4

使用标签扩展

extension UILabel {

    // Pass value for any one of both parameters and see result
    func setLineSpacing(lineSpacing: CGFloat = 0.0, lineHeightMultiple: CGFloat = 0.0) {

        guard let labelText = self.text else { return }

        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = lineSpacing
        paragraphStyle.lineHeightMultiple = lineHeightMultiple

        let attributedString:NSMutableAttributedString
        if let labelattributedText = self.attributedText {
            attributedString = NSMutableAttributedString(attributedString: labelattributedText)
        } else {
            attributedString = NSMutableAttributedString(string: labelText)
        }

        // Line spacing attribute
        attributedString.addAttribute(NSAttributedStringKey.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attributedString.length))

        self.attributedText = attributedString
    }
}

现在调用扩展函数。

let label = UILabel()
let stringValue = "How to\ncontrol\nthe\nline spacing\nin UILabel"

// Pass value for any one argument - lineSpacing or lineHeightMultiple
label.setLineSpacing(lineSpacing: 2.0) .  // try values 1.0 to 5.0

// or try lineHeightMultiple
//label.setLineSpacing(lineHeightMultiple = 2.0) // try values 0.5 to 2.0

或者使用标签实例（只需复制并执行此代码即可查看结果）

let label = UILabel()
let stringValue = "How to\ncontrol\nthe\nline spacing\nin UILabel"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40

// Line spacing attribute
attrString.addAttribute(NSAttributedStringKey.paragraphStyle, value: style, range: NSRange(location: 0, length: stringValue.characters.count))

// Character spacing attribute
attrString.addAttribute(NSAttributedStringKey.kern, value: 2, range: NSMakeRange(0, attrString.length))

label.attributedText = attrString

Swift 3

let label = UILabel()
let stringValue = "Sample text"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40
attrString.addAttribute(NSParagraphStyleAttributeName, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
label.attributedText = attrString

- Krunal

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那个 Swift 4 扩展简直太棒了。谢谢! - David Vincent Gagne

Answer 2

@IBOutlet weak var myLabel: UILabel!
let textForLabel = “Lorem Ipsum is simply dummy text of the printing and 
typesetting industry. Lorem Ipsum has been the industry’s standard dummy text 
ever since the 1500s, when an unknown printer took a galley of type and 
scrambled it to make a type specimen book. It has survived not only five 
centuries, but also the leap into electronic typesetting, remaining 
essentially unchanged.”

let paragraphStyle = NSMutableParagraphStyle()
//line height size
paragraphStyle.lineSpacing = 1.4
let attrString = NSMutableAttributedString(string: titleText)
attrString.addAttribute(NSParagraphStyleAttributeName, value:paragraphStyle, 
range:NSMakeRange(0, attrString.length))
myLabel.attributedText = attrString
myLabel.textAlignment = NSTextAlignment.Center

- Samy Nagy