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crash when set license key


i have a trial key and i am working on ios with the swift. 

I have the latest wikitude SDK.

When application is opened, i have described a constant as -> let wikitudeSDK: WTWikitudeNativeSDK! = nil

So, when view did load -> self.wikitudeSDK.setLicenseKey("My Key")

But application goes to crash and say that "fatal error: unexpectedly found nil while unwrapping an Optional value".

I wonder that what the problem is.

Hello Furkan,

Do you still get a crash or is this issue associated with the one reported here?



Hi Furkan,

The issue you're facing is that you've declared the `wikitudeSDK` variable but did not initialize it (`= nil`).

Typically, you initialize the wikitude SDK in your view controller, once it has loaded all its views.

You should change the `let wikitudeSDK` into`var wikitudeSDK` and in your viewcontroller's `viewDidLoad` initialize it:


self.wikitudeSDK = WTWikitudeNativeSDK(renderingConfiguration: ... , delegate: self)


Only after initialization you can set the license key.

The native code examples should also be able to help you further out I think.

Kind regards,


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