xcode - Class variables not yet supported

Question

I begin my project with a split view controller as initial view controller and start it automatically from storyboard.

Generally, an app with this UI have one and only one split view controller as root, so I create a static variable in the subclass and set it when initialisation was done.

So I want try this behaviour with swift.

I read the Swift programming language guide book on iBook about Type properties (with static and class keyword) and trying a piece of code to the job:

import UIKit

class SplitViewController: UISplitViewController {

    class func sharedInstance() -> SplitViewController {
        return SplitViewController.instance
    }

    class let instance: SplitViewController = nil

    init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        self.initialization()
    }

    init(coder aDecoder: NSCoder!) {
        super.init(coder: aDecoder);
        self.initialization()
    }

    func initialization() {
        SplitViewController.instance = self;
    }
}

but I figured out when Xcode say the class keyword for type properties wasn't supported yet.

Did you have a solution to do this ?

Answer 1

Embedding a struct can work just fine as a workaround:

class SomeClass
{
  // class var classVariable: Int = 0
  // "Class variables not yet supported." Weird.

  // Workaround:
  private struct SubStruct { static var staticVariable: Int = 0 }

  class var workaroundClassVariable: Int
  {
    get { return SubStruct.staticVariable }
    set { SubStruct.staticVariable = newValue }
  }
}

The SomeClass.workaroundClassVariable computed type property can then be used as if it were a stored type property.