Present UIAlertController from AppDelegate [duplicate]

Question

I'm trying to present a UIAlertController from the AppDelegate in my iOS app. Below is the alert and the present method.

UIAlertController *alert = [UIAlertController alertControllerWithTitle:cTitle message:cMessage preferredStyle:UIAlertControllerStyleAlert];

//Configure alert and actions

[self.window.rootViewController presentViewController:alert animated:TRUE completion:nil];

However, when I try to present the alert, it doesn't appear and I get the following alert in the console.

Warning: Attempt to present <UIAlertController: 0x145f5d60> on <UINavigationController: 0x146590f0> whose view is not in the window hierarchy!

What is causing the error and how do I fix it?

Answer 1

You can use this code as well if you want to launch it from didFinishLaunchingWithOptions.Hope this helps.

dispatch_async(dispatch_get_main_queue(), {               let importantAlert: UIAlertController = UIAlertController(title: "Action Sheet", message: "Hello I was presented from appdelegate ;)", preferredStyle: .ActionSheet)             self.window?.rootViewController?.presentViewController(importantAlert, animated: true, completion: nil)         }) 

And up-to-date:

DispatchQueue.main.async {     let alert = UIAlertController(title: "Hello!", message: "Greetings from AppDelegate.", preferredStyle: .alert)     self.window?.rootViewController?.present(alert, animated: true, completion: nil) } 

Answer 2

try this code..

-(void)application:(UIApplication *)application               didReceiveLocalNotification:(UILocalNotification *)notification
{
 NSLog(@"rakshapettu");
 UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"AlertView" message:@"I am an AlertView" preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
                                                      handler:^(UIAlertAction * action) {
                                                          [alert dismissViewControllerAnimated:YES completion:nil];
                                                      }];
[alert addAction:defaultAction];
UIWindow *alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
alertWindow.rootViewController = [[UIViewController alloc] init];
alertWindow.windowLevel = UIWindowLevelAlert + 1;
[alertWindow makeKeyAndVisible];
[alertWindow.rootViewController presentViewController:alert animated:YES completion:nil]; 
}

Answer 3

It's better to use something like:

var hostVC = self.window?.rootViewController

while let next = hostVC?.presentedViewController {
    hostVC = next
}

hostVC?.presentViewController(alertController, animated: true, completion: nil)

Previous answers won't work if you are already presenting modal view controller.