在Swift iOS中添加工具提示指针

import UIKit

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(showTooltip(_:)))
        view.addGestureRecognizer(tapGesture)
    }
    
    @objc func showTooltip(_ sender: UITapGestureRecognizer) {
        let tooltipViewController = UIViewController()
        tooltipViewController.view.backgroundColor = UIColor.lightGray
        
        tooltipViewController.modalPresentationStyle = .popover
        let popoverPresentationController = tooltipViewController.popoverPresentationController
        popoverPresentationController?.sourceView = view
        popoverPresentationController?.sourceRect = sender.view?.bounds ?? CGRect.zero
        popoverPresentationController?.permittedArrowDirections = .up
        
        present(tooltipViewController, animated: true, completion: nil)
    }
}