Present UIAlertController from AppDelegate [duplicate]

Question

This question already has an answer here:

• How to present UIAlertController when not in a view controller? 31 answers

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)
        })

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.

Answer 4

you call it before the window is up and the navigationController is actually shown:

"Warning: Attempt to present on whose view is not in the window hierarchy!"

likely you do so in applicationDidFinishLaunching?

---

EITHER wait .. like do it when the view really appears

OR

one 'hack' would be to force the view and window up yourself:

[self.window addSubview:self.rootViewController.view];
[self.window makeKeyAndVisible];

Answer 5

I was trying the same but does not work because after change of viewcontroller still returned the initial viewcontroller and throw the error whose view is not in the window hierarchy!. Finally, I found the solution to this problem:

UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(alertController, animated: true, completion: nil)

But I have to force view controllers to update de keyWindow with this:

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)
    UIApplication.sharedApplication().keyWindow!.rootViewController = self
    UIApplication.sharedApplication().keyWindow!.makeKeyAndVisible()
}

Answer 6

You can try calling it in viewDidAppear instead of viewDidLoad. I had a similar error and that fixed it.

Answer 7

Using Alert Controller:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
dispatch_async(dispatch_get_main_queue(), {

    //INTERNET NOT AVAILABLE ALERT
    var internetUnavailableAlertController = UIAlertController (title: "Network Unavailable", message: "Please check your internet connection settings and turn on Network Connection", preferredStyle: .Alert)

    var settingsAction = UIAlertAction(title: "Settings", style: .Default) { (_) -> Void in
        let settingsUrl = NSURL(string: UIApplicationOpenSettingsURLString)
        if let url = settingsUrl {
            UIApplication.sharedApplication().openURL(url)
        }
    }
    var cancelAction = UIAlertAction(title: "Okay", style: .Default, handler: nil)
    internetUnavailableAlertController .addAction(settingsAction)
    internetUnavailableAlertController .addAction(cancelAction)
    self.window?.rootViewController!.presentViewController(internetUnavailableAlertController , animated: true, completion: nil)
    })

Using AlertView:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    dispatch_async(dispatch_get_main_queue(), {

        //INTERNET NOT AVAILABLE ALERTVIEW

        let internetUnavailableAlert =  UIAlertView(title: "Network Unavailable", message: "Please check your internet connection settings and turn on Network Connection", delegate: self, cancelButtonTitle: "Okay")
        internetUnavailableAlert.show()
        })

  return true
 }
}