Does UIWindow function not work in Xcode11.3? - ios

Question

I have alertcontroller code like this.
But I try to present alert, the alert don't show to me.
Have any idea to me.
Thanks.
public extension UIAlertController {
func show() {
let win = UIWindow(frame: UIScreen.main.bounds)
let vc = UIViewController()
vc.view.backgroundColor = .clear
win.rootViewController = vc
win.windowLevel = UIWindow.Level.alert + 1
win.makeKeyAndVisible()
vc.present(self, animated: true, completion: nil)
}
}
let alertController = UIAlertController(title: newTitle, message: newMessage, preferredStyle: .alert)
let submit = UIAlertAction(title: submitTitle, style: .default) { (action) in
clickOK()
}
alertController.addAction(submit)
if let cancelTitle = cancelTitle, !cancelTitle.isEmpty {
let cancel = UIAlertAction(title: cancelTitle, style: .cancel) { (action) in
if let clickCancel = clickCancel {
clickCancel()
}
}
alertController.addAction(cancel)
}
alertController.show()

Answer 1

Seems you need to hold UIWindow object until you want to show alert
Here is working code with little changes
private var win: UIWindow!
extension UIAlertController {
func show() {
win = UIWindow(frame: UIScreen.main.bounds)
let vc = UIViewController()
vc.view.backgroundColor = .clear
win.rootViewController = vc
win.windowLevel = .alert + 1
win.makeKeyAndVisible()
win.rootViewController?.present(self, animated: true, completion: nil)
}
open override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
win = nil
}
}
usage
Use in same way as you were previously using
let alertController = UIAlertController(title: newTitle, message: newMessage, preferredStyle: .alert)
let submit = UIAlertAction(title: submitTitle, style: .default) { (action) in
clickOK()
}
alertController.addAction(submit)
if let cancelTitle = cancelTitle, !cancelTitle.isEmpty {
let cancel = UIAlertAction(title: cancelTitle, style: .cancel) { (action) in
if let clickCancel = clickCancel {
clickCancel()
}
}
alertController.addAction(cancel)
}
alertController.show()

Answer 2

You can use this swift 5.0 extension also
public extension UIAlertController {
func showAlert() {
let window = UIWindow(frame: UIScreen.main.bounds)
let vc = UIViewController()
vc.view.backgroundColor = .clear
window.rootViewController = vc
window.windowLevel = UIWindow.Level.alert + 1
window.makeKeyAndVisible()
vc.present(self, animated: true, completion: nil)
}
}
Setup your alert controller with title and message and call like this
alertObject.showAlert()