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
    }
}

简单的方法

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        self.view.addSubview(makeLabel("my title",x: 0, y: 100, w: 320, h: 30))
    }

    func makeLabel(title:String, x:CGFloat, y:CGFloat, w:CGFloat, h:CGFloat)->UILabel{
        var myLabel : UILabel = UILabel(frame: CGRectMake(x,y,w,h))
        myLabel.textAlignment = NSTextAlignment.Right

        // inser last char to right
        var titlePlus1char = "\(title)1"
        myLabel.text = titlePlus1char
        var titleSize:Int = count(titlePlus1char)-1

        myLabel.textColor = UIColor(red:1.0, green:1.0,blue:1.0,alpha:1.0)
        myLabel.backgroundColor = UIColor(red: 214/255, green: 167/255, blue: 0/255,alpha:1.0)


        // create myMutable String
        var myMutableString = NSMutableAttributedString()

        // create myMutable font
        myMutableString = NSMutableAttributedString(string: titlePlus1char, attributes: [NSFontAttributeName:UIFont(name: "HelveticaNeue", size: 20)!])

        // set margin size
        myMutableString.addAttribute(NSFontAttributeName, value: UIFont(name: "HelveticaNeue", size: 10)!, range: NSRange(location: titleSize,length: 1))

        // set last char to alpha 0
        myMutableString.addAttribute(NSForegroundColorAttributeName, value: UIColor(red:1.0, green:1.0,blue:1.0,alpha:0), range: NSRange(location: titleSize,length: 1))

        myLabel.attributedText = myMutableString

        return myLabel
    }


    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

斯威夫特 4+

let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.firstLineHeadIndent = 10

// Swift 4.2++
label.attributedText = NSAttributedString(string: "Your text", attributes: [NSAttributedString.Key.paragraphStyle: paragraphStyle])

// Swift 4.1--
label.attributedText = NSAttributedString(string: "Your text", attributes: [NSAttributedStringKey.paragraphStyle: paragraphStyle])

子类UILabel。(File-New-File- CocoaTouchClass-make UILabel的子类)。

//  sampleLabel.swift

import UIKit

class sampleLabel: UILabel {

 let topInset = CGFloat(5.0), bottomInset = CGFloat(5.0), leftInset = CGFloat(8.0), rightInset = CGFloat(8.0)

 override func drawTextInRect(rect: CGRect) {

  let insets: UIEdgeInsets = UIEdgeInsets(top: topInset, left: leftInset, bottom: bottomInset, right: rightInset)
  super.drawTextInRect(UIEdgeInsetsInsetRect(rect, insets))

 }
 override func intrinsicContentSize() -> CGSize {
  var intrinsicSuperViewContentSize = super.intrinsicContentSize()
  intrinsicSuperViewContentSize.height += topInset + bottomInset
  intrinsicSuperViewContentSize.width += leftInset + rightInset
  return intrinsicSuperViewContentSize
 }
}

ViewController:

override func viewDidLoad() {
  super.viewDidLoad()

  let labelName = sampleLabel(frame: CGRectMake(0, 100, 300, 25))
  labelName.text = "Sample Label"
  labelName.backgroundColor =  UIColor.grayColor()

  labelName.textColor = UIColor.redColor()
  labelName.shadowColor = UIColor.blackColor()
  labelName.font = UIFont(name: "HelveticaNeue", size: CGFloat(22))
  self.view.addSubview(labelName)
 }

或者将Storyboard上的自定义UILabel类关联为Label的类。

斯威夫特 4+

class EdgeInsetLabel: UILabel {
    var textInsets = 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: -textInsets.top,
                                          left: -textInsets.left,
                                          bottom: -textInsets.bottom,
                                          right: -textInsets.right)
        return textRect.inset(by: invertedInsets)
    }

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

用法:

let label = EdgeInsetLabel()
label.textInsets = UIEdgeInsets(top: 2, left: 6, bottom: 2, right: 6)

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!