iOS nil found while unwrapping optional value

[theprizerevealed]

I am using this line of code

 self.view.window!.rootViewController?.dismiss(animated: false, completion: nil)

in my app and sometimes, though not always, Xcode will tell me the error message 'nil found while unwrapping optional value', while using the Simulator. I can't seem to replicate the behavior that triggers this error message. Any ideas?

 

[theprizerevealed]

I am wondering if optional binding or optional chaining is the solution to this problem as discussed here:
https://learnappmaking.com/found-nil-while-unwrapping-optional-value/

 

[PhoneyDeveloper]

Force unwrapping is usually a bad idea unless you're certain that the optional can't be nil. You can easily fix this by changing the ! to a ?. I can't say why the window might be nil but that looks like the only part of that expression that can cause that error.

 

[KALLT]

Adding a ? here would prevent the app from crashing, but it also stops this method from being called, without giving you immediate feedback.

It is generally useful to check the documentation in which case a property may be nil. For instance, the window property of UIView is nil if the view has not yet been added to a window.