How to show UIAlertController from Appdelegate
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.! =)
Anbu.Karthik's answer but in Swift 4.1
var topWindow: UIWindow? = UIWindow(frame: UIScreen.main.bounds)
topWindow?.rootViewController = UIViewController()
topWindow?.windowLevel = UIWindowLevelAlert + 1
let alert: UIAlertController = UIAlertController(title: "APNS", message: "received Notification", preferredStyle: .alert)
alert.addAction(UIAlertAction.init(title: "OK", style: .default, handler: { (alertAction) in
topWindow?.isHidden = true
topWindow = nil
}))
topWindow?.makeKeyAndVisible()
topWindow?.rootViewController?.present(alert, animated: true, completion:nil)
Thanks for reading this.
try this
Objective-C
UIWindow* topWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
topWindow.rootViewController = [UIViewController new];
topWindow.windowLevel = UIWindowLevelAlert + 1;
UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"APNS" message:@"received Notification" preferredStyle:UIAlertControllerStyleAlert];
[alert addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK",@"confirm") style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
// continue your work
// important to hide the window after work completed.
// this also keeps a reference to the window until the action is invoked.
topWindow.hidden = YES; // if you want to hide the topwindow then use this
topWindow = nil; // if you want to remove the topwindow then use this
}]];
[topWindow makeKeyAndVisible];
[topWindow.rootViewController presentViewController:alert animated:YES completion:nil];
Swift3 and above
var topWindow: UIWindow? = UIWindow(frame: UIScreen.main.bounds)
topWindow?.rootViewController = UIViewController()
topWindow?.windowLevel = UIWindow.Level.alert + 1
let alert = UIAlertController(title: "APNS", message: "received Notification", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel) { _ in
// continue your work
// important to hide the window after work completed.
// this also keeps a reference to the window until the action is invoked.
topWindow?.isHidden = true // if you want to hide the topwindow then use this
topWindow = nil // if you want to hide the topwindow then use this
})
topWindow?.makeKeyAndVisible()
topWindow?.rootViewController?.present(alert, animated: true, completion: nil)
Detail description: http://www.thecave.com/2015/09/28/how-to-present-an-alert-view-using-uialertcontroller-when-you-dont-have-a-view-controller/