斯威夫特4

易于使用的解决方案，可用于项目中的所有UILabel子。

例子:

let label = UILabel()
    label.<Do something>
    label.padding = UIEdgeInsets(top: 0, left: 16, bottom: 0, right: 0)

UILabel扩展

import UIKit

extension UILabel {
    private struct AssociatedKeys {
        static var padding = UIEdgeInsets()
    }

    public var padding: UIEdgeInsets? {
        get {
            return objc_getAssociatedObject(self, &AssociatedKeys.padding) as? UIEdgeInsets
        }
        set {
            if let newValue = newValue {
                objc_setAssociatedObject(self, &AssociatedKeys.padding, newValue as UIEdgeInsets?, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            }
        }
    }

    override open func draw(_ rect: CGRect) {
        if let insets = padding {
            self.drawText(in: rect.inset(by: insets))
        } else {
            self.drawText(in: rect)
        }
    }

    override open var intrinsicContentSize: CGSize {
        guard let text = self.text else { return super.intrinsicContentSize }

        var contentSize = super.intrinsicContentSize
        var textWidth: CGFloat = frame.size.width
        var insetsHeight: CGFloat = 0.0
        var insetsWidth: CGFloat = 0.0

        if let insets = padding {
            insetsWidth += insets.left + insets.right
            insetsHeight += insets.top + insets.bottom
            textWidth -= insetsWidth
        }

        let newSize = text.boundingRect(with: CGSize(width: textWidth, height: CGFloat.greatestFiniteMagnitude),
                                        options: NSStringDrawingOptions.usesLineFragmentOrigin,
                                        attributes: [NSAttributedString.Key.font: self.font], context: nil)

        contentSize.height = ceil(newSize.size.height) + insetsHeight
        contentSize.width = ceil(newSize.size.width) + insetsWidth

        return contentSize
    }
}

一个实用的解决方案是添加与主标签高度和颜色相同的空白标签。将主标签的前导/尾距设置为零，对齐垂直中心，并设置所需的宽度。

Swift 3代码及其实现示例

class UIMarginLabel: UILabel {

    var topInset:       CGFloat = 0
    var rightInset:     CGFloat = 0
    var bottomInset:    CGFloat = 0
    var leftInset:      CGFloat = 0

    override func drawText(in rect: CGRect) {
        let insets: UIEdgeInsets = UIEdgeInsets(top: self.topInset, left: self.leftInset, bottom: self.bottomInset, right: self.rightInset)
        self.setNeedsLayout()
        return super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
    }
}

class LabelVC: UIViewController {

    //Outlets
    @IBOutlet weak var labelWithMargin: UIMarginLabel!

    override func viewDidLoad() {
        super.viewDidLoad()

        //Label settings.
        labelWithMargin.leftInset = 10
        view.layoutIfNeeded()
    }
}

不要忘记在故事板标签对象中添加类名UIMarginLabel。 编码快乐!

只需使用一个UIView作为一个superview，并定义一个固定的边距标签与自动布局。

斯威夫特3

import UIKit

class PaddingLabel: UILabel {

   @IBInspectable var topInset: CGFloat = 5.0
   @IBInspectable var bottomInset: CGFloat = 5.0
   @IBInspectable var leftInset: CGFloat = 5.0
   @IBInspectable var rightInset: CGFloat = 5.0

   override func drawText(in rect: CGRect) {
      let insets = UIEdgeInsets(top: topInset, left: leftInset, bottom: bottomInset, right: rightInset)
      super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
   }

   override var intrinsicContentSize: CGSize {
      get {
         var contentSize = super.intrinsicContentSize
         contentSize.height += topInset + bottomInset
         contentSize.width += leftInset + rightInset
         return contentSize
      }
   }
}

如果你想使用UILabel

class UILabel : UIKit.UILabel {
    var insets = UIEdgeInsets.zero {
        didSet { invalidateIntrinsicContentSize() }
    }

    override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {
        let textRect = super.textRect(forBounds: bounds, limitedToNumberOfLines: numberOfLines)
        let invertedInsets = UIEdgeInsets(top: -insets.top,
                                          left: -insets.left,
                                          bottom: -insets.bottom,
                                          right: -insets.right)
        return textRect.inset(by: invertedInsets)
    }

    override func drawText(in rect: CGRect) {
        super.drawText(in: rect.inset(by: insets))
    }
}