如何使用SpriteKit

Question

我正在尝试将插页式广告AdMob应用到我的游戏应用中。但到目前为止我没有太多运气。代码似乎没有错误，但它不显示应用程序。任何帮助都会非常感激。谢谢！ 这是我的代码：

import UIKit
import SpriteKit
import GoogleMobileAds

class GameViewController: UIViewController, GADInterstitialDelegate {

    var interstitial: GADInterstitial!

    override func viewDidLoad() {
        super.viewDidLoad()

        if let scene = GameScene(fileNamed:"GameScene") {
            // Configure the view.



            let skView = self.view as! SKView
            skView.showsFPS = true
            skView.showsNodeCount = true

            /* Sprite Kit applies additional optimizations to improve rendering performance */
            skView.ignoresSiblingOrder = true

            /* Set the scale mode to scale to fit the window */
            scene.scaleMode = .AspectFill

            skView.presentScene(scene)


        }


        interstitial = GADInterstitial(adUnitID: "ca-app-pub-5713504307801022/7610056592")


        let request = GADRequest()
        interstitial.loadRequest(request)

        func CreateAD() -> GADInterstitial {

            let interstital = GADInterstitial(adUnitID: "ca-app-pub-5713504307801022/7610056592")
            interstitial.loadRequest(GADRequest())
            return interstital

        }


        if gameOver == true {


            if (interstitial.isReady){
                interstitial.presentFromRootViewController(self)
                interstitial = CreateAD()

            }

        }

    }