navigationController!.pushViewController giving Fatal error: Unexpectedly found nil while unwrapping an Optional value:

Question

I am trying to navigate from one Storyboard to another Storyboard. Here is my code -

  let storyboard = UIStoryboard(name: "Main", bundle: nil)
                     let controller = storyboard.instantiateViewController(withIdentifier: "detail") as! detailsArticle
                     controller.jsonData = json2["post"]
                    
                    self.navigationController!.pushViewController(controller, animated: true)

However, when I try to navigate after clicking the button which runs the above code, I get exception error:

Fatal error: Unexpectedly found nil while unwrapping an Optional value: file

How do I solve this?

self.navigationController!.pushViewController(controller, animated: true) — GoSSDHosting, Jul 17 '20 at 22:21

Frankenstein · Accepted Answer · 2020-07-17T22:42:01.007

1

There are 2 places you could be getting the crash.

The identifier of the detailsArticle is not set as "detail".
The controller you're trying to push onto is not embedded in navigationController.

Try running and check the console to see the debug messages I've added:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
guard let controller = storyboard.instantiateViewController(withIdentifier: "detail") as? detailsArticle else { print("detail vc id not set"); return }
controller.jsonData = json2["post"]
guard let navigationController = navigationController else { print("this vc is not embedded in navigationController"); return }
navigationController.pushViewController(controller, animated: true)

From the comments it's the 2nd one causing the issue. To fix it here are the steps:

Go to <StoryboardName>.storyboard where the current UIViewController sub-class is located and select the current UIViewController scene.
From the Menu bar choose Editor and Embedd In and select Navigation Controller.

edited Jul 17 '20 at 22:42

answered Jul 17 '20 at 22:07

Frankenstein

15,732
4
22
47

Its giving this vc is not embedded in navigationController.. How do I embed it in navigationcontroller? – GoSSDHosting Jul 17 '20 at 22:19
The code which I have shown is for another storyboard Xyz and not main.storyboard. Do I have to embed navigation controller in Xyz or main? – GoSSDHosting Jul 17 '20 at 22:37
However, detailsArticle is in main.storyboard – GoSSDHosting Jul 17 '20 at 22:39
You should probably go to xyz where the current view controller is located. – Frankenstein Jul 17 '20 at 22:40
please check ur mail – GoSSDHosting Jul 17 '20 at 22:52
are you still not able to fix it? I don't think it's so hard to embed a VC in nav VC. – Frankenstein Jul 18 '20 at 06:57

navigationController!.pushViewController giving Fatal error: Unexpectedly found nil while unwrapping an Optional value:

1 Answers1