Attempt to present UIViewController on UIViewController whose view is not in the window hierarchy

Question

Just started using Xcode 4.5 and I got this error in the console:

Warning: Attempt to present < finishViewController: 0x1e56e0a0 > on < ViewCont

Answer 1

I've ended up with such a code that finally works to me (Swift), considering you want to display some viewController from virtually anywhere. This code will obviously crash when there is no rootViewController available, that's the open ending. It also does not include usually required switch to UI thread using

dispatch_sync(dispatch_get_main_queue(), {
    guard !NSBundle.mainBundle().bundlePath.hasSuffix(".appex") else {
       return; // skip operation when embedded to App Extension
    }

    if let delegate = UIApplication.sharedApplication().delegate {
        delegate.window!!.rootViewController?.presentViewController(viewController, animated: true, completion: { () -> Void in
            // optional completion code
        })
    }
}