Adding @objc(NewClassName) breaks Storyboard references in Swift

Question

I was wondering if anyone else had run into this problem;

I need to add the line @objc(NewClassName) to my View Controller so that it can be seen by its Objective-C counterparts with an Objective-C prefixed class name.

import UIKit

@objc(NewClassName)

class ClassName: UIViewController {

• View Controller code is written in Swift
• Storyboard references work fine without the @objc line

• Adding the @objc line gives the error:

  *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIViewController 0x17f62f70> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key mainView.'
  

Note: mainView is a View I have added myself. This error does not crop up without the @objc

Removing the @objc line makes it all work as intended.

This is how it is set up in the Storyboard:

Answer 1

You need to update the storyboard class name to NewClassName. The runtime doesn't find ClassName and instantiates a generic UIViewController, causing the exception.