in iOS 13 [UIApplication sharedApplication] delegate].window does not work using objective-c

Question

I need to display alert from a class which is non-UIView using objective-c.

Below is the code:

 UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@“Sample” message message:@“hello message” preferredStyle:UIAlertControllerStyleAlert];

[alertVC addAction:[UIAlertAction actionWithTitle:@"Okay" style:UIAlertActionStyleCancel handler:^(UIAlertAction * action) {}]];

[[[UIApplication sharedApplication] delegate].window.rootViewController presentViewController:alertVC animated:YES completion:nil];

this above does not work anymore and I could not any other alternative for same code in objective-c. I came across this link How to resolve: 'keyWindow' was deprecated in iOS 13.0 but solution is in Swift,not in objective-c .

Thanks

just try the same words in objective c – Lena Bru Feb 03 '20 at 16:18 — Lena Bru, Feb 03 '20 at 16:18

score 1 · Answer 1 · answered Feb 03 '20 at 16:31

1

The problem is that in iOS 13, this expression...

[[UIApplication sharedApplication] delegate].window.rootViewController

...is nil. That's because the window property belongs to the scene delegate, not the app delegate. You would do better to access the window by way of the UIApplication itself. For example, look through the application's windows and find the one that is key.

answered Feb 03 '20 at 16:31

matt

515,959
87
875
1,141

For Objective-C code, see https://stackoverflow.com/a/58447461/341994 – matt Feb 03 '20 at 16:31

score 1 · Answer 2 · answered Feb 04 '20 at 07:56

You are trying to present the viewcontroller in key window which will create exception. Try this code

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Tap!" message:message preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *action = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
[alert addAction:action];
[self presentViewController:alert animated:YES completion:nil];

score 0 · Answer 3 · answered Feb 03 '20 at 16:22

0

I think in your case most simple would be to use the following as replacement of your last code row

[UIApplication.sharedApplication.windows.lastObject.rootViewController 
    presentViewController:alertVC animated:YES completion:nil];

answered Feb 03 '20 at 16:22

Asperi

228,894
20
464
690

@sia, would my additional answer yes changed anything? )) ... give it a chance - try! – Asperi Feb 03 '20 at 16:34

in iOS 13 [UIApplication sharedApplication] delegate].window does not work using objective-c

3 Answers3