无论视图层次结构如何，都要在顶部显示UIAlertController

我想创建一个帮助类，用于展示UIAlertController。由于它是一个辅助类，我希望它能够在任何视图层次结构中使用，而且不需要关于视图的任何信息。我可以显示警告，但当警告被取消时，应用程序崩溃并出现以下错误：

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: 'Trying to dismiss UIAlertController <UIAlertController: 0x135d70d80>
 with unknown presenter.'

我正在使用以下代码创建弹出窗口：

guard let window = UIApplication.shared.keyWindow else { return }
let view = UIView()
view.isUserInteractionEnabled = true
window.insertSubview(view, at: 0)
window.bringSubview(toFront: view)
// add full screen constraints to view ...

let controller = UIAlertController(
  title: "confirm deletion?",
  message: ":)",
  preferredStyle: .alert
)

let deleteAction = UIAlertAction(
  title: "yes",
  style: .destructive,
  handler: { _ in
    DispatchQueue.main.async {
      view.removeFromSuperview()
      completion()
    }
  }
)
controller.addAction(deleteAction)

view.insertSubview(controller.view, at: 0)
view.bringSubview(toFront: controller.view)
// add centering constraints to controller.view ...

当我点击yes时，应用程序会崩溃并且处理程序在崩溃之前没有被触发。我无法呈现UIAlertController，因为这将取决于当前视图层次结构，而我希望弹出窗口是独立的。

编辑：Swift解决方案 感谢@Vlad提供的想法。似乎在单独的窗口中操作要简单得多。所以这里是一个可行的Swift解决方案：

class Popup {
  private var alertWindow: UIWindow
  static var shared = Popup()

  init() {
    alertWindow = UIWindow(frame: UIScreen.main.bounds)
    alertWindow.rootViewController = UIViewController()
    alertWindow.windowLevel = UIWindowLevelAlert + 1
    alertWindow.makeKeyAndVisible()
    alertWindow.isHidden = true
  }

  private func show(completion: @escaping ((Bool) -> Void)) {
    let controller = UIAlertController(
      title: "Want to do it?",
      message: "message",
      preferredStyle: .alert
    )

    let yesAction = UIAlertAction(
      title: "Yes",
      style: .default,
      handler: { _ in
        DispatchQueue.main.async {
          self.alertWindow.isHidden = true
          completion(true)
        }
    })

    let noAction = UIAlertAction(
      title: "Not now",
      style: .destructive,
      handler: { _ in
        DispatchQueue.main.async {
          self.alertWindow.isHidden = true
          completion(false)
        }
    })

    controller.addAction(noAction)
    controller.addAction(yesAction)
    self.alertWindow.isHidden = false
    alertWindow.rootViewController?.present(controller, animated: false)
  }
}