这里提到的解决方案对我不起作用。我发现了一个稍微不同的方式来做它与iOS 6 NSAttributeString:

myLabel.numberOfLines = 0; 
NSString* string = @"String with line one. \n Line two. \n Line three.";
NSMutableParagraphStyle *style  = [[NSMutableParagraphStyle alloc] init];
style.minimumLineHeight = 30.f;
style.maximumLineHeight = 30.f;
NSDictionary *attributtes = @{NSParagraphStyleAttributeName : style,};
myLabel.attributedText = [[NSAttributedString alloc] initWithString:string
                                                         attributes:attributtes];   
[myLabel sizeToFit];

根据@Mike的回答，减少lineHeightMultiple是关键点。下面的例子，它很适合我:

NSString* text = label.text;
CGFloat textWidth = [text sizeWithAttributes:@{NSFontAttributeName: label.font}].width;
if (textWidth > label.frame.size.width) {
  NSMutableParagraphStyle *paragraph = [[NSMutableParagraphStyle alloc] init];
  paragraph.alignment = NSTextAlignmentCenter;
  paragraph.lineSpacing = 1.0f;
  paragraph.lineHeightMultiple = 0.75;     // Reduce this value !!!
  NSMutableAttributedString* attrText = [[NSMutableAttributedString alloc] initWithString:text];
  [attrText addAttribute:NSParagraphStyleAttributeName value:paragraph range:NSMakeRange(0, text.length)];
  label.attributedText = attrText;
}

在Swift中，作为一个函数，灵感来自DarkDust

// Usage: setTextWithLineSpacing(myEpicUILabel,text:"Hello",lineSpacing:20)
func setTextWithLineSpacing(label:UILabel,text:String,lineSpacing:CGFloat)
{
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.lineSpacing = lineSpacing

    let attrString = NSMutableAttributedString(string: text)
    attrString.addAttribute(NSAttributedString.Key.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attrString.length))

    label.attributedText = attrString
}

这应该会有帮助。然后你可以将你的标签分配给故事板中的这个自定义类，并直接在属性中使用它的参数:

open class SpacingLabel : UILabel {

    @IBInspectable open var lineHeight:CGFloat = 1 {
        didSet {
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.lineSpacing = 1.0
            paragraphStyle.lineHeightMultiple = self.lineHeight
            paragraphStyle.alignment = self.textAlignment

            let attrString = NSMutableAttributedString(string: self.text!)
            attrString.addAttribute(NSAttributedStringKey.font, value: self.font, range: NSMakeRange(0, attrString.length))
            attrString.addAttribute(NSAttributedStringKey.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attrString.length))
            self.attributedText = attrString
        }
    } 
}

从接口生成器(Storyboard/XIB):

编程:

斯威夫特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(只要复制并执行这段代码就可以看到结果)

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

斯威夫特3

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
attrString.addAttribute(NSParagraphStyleAttributeName, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
label.attributedText = attrString

下面是UILabel的一个子类，它设置lineHeightMultiple并确保内在高度足够大，不会截断文本。

@IBDesignable
class Label: UILabel {
    override var intrinsicContentSize: CGSize {
        var size = super.intrinsicContentSize
        let padding = (1.0 - lineHeightMultiple) * font.pointSize
        size.height += padding
        return size
    }

    override var text: String? {
        didSet {
            updateAttributedText()
        }
    }

    @IBInspectable var lineHeightMultiple: CGFloat = 1.0 {
        didSet {
            updateAttributedText()
        }
    }

    private func updateAttributedText() {
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineHeightMultiple = lineHeightMultiple
        attributedText = NSAttributedString(string: text ?? "", attributes: [
            .font: font,
            .paragraphStyle: paragraphStyle,
            .foregroundColor: textColor
        ])
        invalidateIntrinsicContentSize()
    }
}