给文本标签UILabel添加长按复制功能

class CopyLabel: UILabel {
    override init(frame: CGRect) {
        super.init(frame: frame)
        userInteractionEnabled = true
        let longPress = UILongPressGestureRecognizer(target: self,
                                                     action: #selector(handleLongPress(_:)))
        addGestureRecognizer(longPress)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func canBecomeFocused() -> Bool {
        return true
    }
    
    override func canPerformAction(action: Selector, withSender sender: AnyObject?) -> Bool {
        return action == #selector(NSObject.copy(_:))
    }
    
    override func copy(sender: AnyObject?) {
        let pBoard = UIPasteboard.generalPasteboard()
        pBoard.string = self.text
    }
    
    func handleLongPress(gesture: UILongPressGestureRecognizer) {
        self.becomeFirstResponder()
        let menu = UIMenuController.sharedMenuController()
        menu.setTargetRect(self.frame, inView: self)
        menu.setMenuVisible(true, animated: true)
    }
}