TextKit 自定义UILabel识别链接

1. 继承 DemoLabel.swift 文件，继承 UILabel

class DemoLabel: UILabel {
    
    //MARK: - 重写属性
    override var text: String?{
        didSet{
            prepareText()
        }
    }
    
    override var attributedText: NSAttributedString?{
        didSet{
            prepareText()
        }
    }
    //MARK:  - 绘制文本
    override func draw(_ rect: CGRect) {
        //区域
        let range = NSRange(location: 0, length: textStorage.length)
        //绘制 - 布局管理器绘制 textStorage 中的内容
        layoutManager.drawGlyphs(forGlyphRange: range, at: CGPoint.zero)
    }
    
    //MARK: - 构造函数
    override init(frame: CGRect) {
        super.init(frame: frame)
        prepareTextSystem()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        prepareTextSystem()
    }
    
    //准备文本系统
    private func prepareTextSystem(){
        //1.准备文本
        prepareText()
        //2.设置对象关系
        textStorage.addLayoutManager(layoutManager)
        layoutManager.addTextContainer(textContainer)
    }
    
    ///准备文本内容
    private func prepareText(){
        if attributedText != nil{
            //直接设置属性文本
            textStorage.setAttributedString(attributedText!)
        }else if text != nil{
            textStorage.setAttributedString(NSAttributedString(string: text!))
        }else {
            textStorage.setAttributedString(NSAttributedString(string: ""))
        }
        //print(rangeForUrls)
        //遍历 url 数组，设置文本属性
        guard let rangeForUrls = rangeForUrls else{
            return
        }
        for range in rangeForUrls{
            textStorage.addAttribute(.foregroundColor, value: UIColor.blue, range: range)
        }
        
    }
    
    /// 准备文本内容
    override func layoutSubviews() {
        super.layoutSubviews()
        //设置文本容器的尺寸
        textContainer.size = bounds.size
    }
    
  //MARK: - 懒加载属性
   //文本内容 - 可变属性字符串的子类
  private lazy var textStorage = NSTextStorage()
    //布局管理器-负责文本绘制
  private lazy var layoutManager = NSLayoutManager()
    //文本容器 - 设置绘制的尺寸
  private lazy var textContainer = NSTextContainer()
    
}

//MARK: - 正则表达式相关函数/属性
extension DemoLabel{
    ///返回字符串中所有 URL 链接的范围数组
    var rangeForUrls: [NSRange]?{
        //1.定义正则表达式
        let pattern = "[a-zA-Z]*://[a-zA-Z0-9/\\.]*"
        let regex = try! NSRegularExpression(pattern: pattern, options: [])
        //2.匹配所有的 url 链接
        let result = regex.matches(in: textStorage.string, options: [], range: NSRange(location: 0, length: textStorage.length))
        var array = [NSRange]()
        for m in result {
            array.append(m.range(at: 0))
        }
        return array
    }
}

2. 在 Main.storyboard 中添加 UILabel 控件，进行测试

@IBOutlet weak var label: DemoLabel!
    
  override func viewDidLoad() {
        super.viewDidLoad()
        label.text = "http://www.apple.com http://www.hh.cn"
    }