How to constantly update the text of ULabel in Swift

Overview I'm building a simple project where I have a textView and a label. I want the label content to change every time the user copies a word from the textView and display it. At the moment I'm not able to do it automatically.

What I'm doing

class ViewController: UIViewController {
    
    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var refresh: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        label.text = UIPasteboard.general.string
        
        refresh.addTarget(self, action: #selector(displayNew), for: .touchUpInside)
    }
    
    @objc func displayNew(){
        label.text = UIPasteboard.general.string
    }
}

So whenever the user presses the refresh button the label's text refreshes. Now I need it to happen automatically.

Question
How would ypu refresh the label's text automatically whenever the user copies something?

Solution

Add a listener

NotificationCenter.default.addObserver(self, selector: #selector(clipChange),
                                           name: UIPasteboard.changedNotification, object: nil)

@objc func clipChange(){
    label.text = UIPasteboard.general.string 
}