John John - 3 months ago 34
Objective-C Question

How to present UIAlertController from SKScene

I'm working in Spritekit and I'm trying to present a UIAlertController from my SKScene, but I am having trouble doing it. I've watched several tutorials but none of the UIAlertController tutorials have been specific to Spritekit. I keep seeing this code below, but it has not been effective since SKScene is not a UIViewController.

[self presentViewController:self animated:YES completion:nil];


I have the rest of the relative code below. Can anybody please help me present my UIAlerController on my SKScene.

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"You Lose!" message:@"Do You Want To Beat This Level?" preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *CancelButton = [UIAlertAction actionWithTitle:@"GiveUp" style:UIAlertControllerStyleAlert handler:<#^(UIAlertAction *action)handler#>]

Answer

The SKScene instance can't invoke presentViewController(_:animated:completion) because it is not a subclass of UIViewController. However, if you rewrite as such, your alert will launch:

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

ps: there will be a warning though that Attempt to present <UIAlertController: 0x7fc31eb32e50> on <Sample_Game.GameViewController: 0x7fc31bd9b4f0> which is already presenting. If anyone knows how to eradicate this warning, that will be great.


[Updated 11 August 2016]

To eradicate the aforementioned warning, check if the rootViewController has presented a view controller:

 let vc = self.view?.window?.rootViewController
 if vc.presentedViewController == nil {
    vc.presentViewController(alert, animated: true, completion: nil)
 }
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