如何在ViewController中显示弹出窗口

// 弹出窗口的视图控制器
class PopupViewController: UIViewController {
    // 弹出窗口的内容视图
    let popupView = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置弹出窗口的样式和大小
        popupView.backgroundColor = .white
        popupView.frame = CGRect(x: 0, y: 0, width: 200, height: 200)
        popupView.center = view.center
        
        // 添加关闭按钮
        let closeButton = UIButton(type: .system)
        closeButton.setTitle("关闭", for: .normal)
        closeButton.addTarget(self, action: #selector(closeButtonTapped), for: .touchUpInside)
        closeButton.frame = CGRect(x: 0, y: 0, width: 80, height: 40)
        closeButton.center = CGPoint(x: popupView.bounds.width / 2, y: popupView.bounds.height - 40)
        popupView.addSubview(closeButton)
        
        // 将弹出窗口的视图添加到当前视图控制器的视图层级中
        view.addSubview(popupView)
    }
    
    @objc func closeButtonTapped() {
        // 关闭弹出窗口
        dismiss(animated: true, completion: nil)
    }
}

// 在ViewController中显示弹出窗口
class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 添加一个按钮，点击时显示弹出窗口
        let showPopupButton = UIButton(type: .system)
        showPopupButton.setTitle("显示弹出窗口", for: .normal)
        showPopupButton.addTarget(self, action: #selector(showPopupButtonTapped), for: .touchUpInside)
        showPopupButton.frame = CGRect(x: 0, y: 0, width: 200, height: 40)
        showPopupButton.center = view.center
        view.addSubview(showPopupButton)
    }
    
    @objc func showPopupButtonTapped() {
        // 实例化并显示弹出窗口的视图控制器
        let popupViewController = PopupViewController()
        popupViewController.modalPresentationStyle = .overCurrentContext
        present(popupViewController, animated: true, completion: nil)
    }
}