How to show UIAlertController from Appdelegate

Question

I\'m working with PushNotification on iOS app. I would like to show a UIalertcontroller when the app receive a notification.

I try this code below in the AppDelegate

Answer 1

Shortest & Simplest :

Create a extension :

extension UIApplication {
class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
    if let navigationController = controller as? UINavigationController {
        return topViewController(controller: navigationController.visibleViewController)
    }
    if let tabController = controller as? UITabBarController {
        if let selected = tabController.selectedViewController {
            return topViewController(controller: selected)
        }
    }
    if let presented = controller?.presentedViewController {
        return topViewController(controller: presented)
    }
    return controller
} }

and then use it anywhere like

UIApplication.topViewController()?.present(UIViewController, animated: true, completion: nil)

With this you can present Alert or anything Anywhere Example :

let alert = UIAlertController(title: "Your title", message: "Your message", preferredStyle: .alert)
let cancelButton = UIAlertAction(title: "Ok", style: .cancel, handler: nil)
alert.addAction(cancelButton)
UIApplication.topViewController()?.present(alert, animated: true, completion: nil)

ALTERNATE METHOD :

No need to create any Extension or any method or anything simply write the above 3 lines for creating an Alert and for presenting use :

self.window?.rootViewController?.present(alert, animated: true, completion: nil)

That's it.! =)