没有向广告提供 UIViewController。无法继续

No UIViewController supplied to the ad. Cannot continue

我有一个 sprite-kit 游戏,第一个广告在 gameOver 上加载,但随后的 gameOver 出现以下错误:

<Google> No UIViewController supplied to the ad. Cannot continue.

我的代码是这样的:

initWithSize:

-(id)initWithSize:(CGSize)size { 
    if (...]) {
        ...

        self.interstitial = [[GADInterstitial alloc] init];
        self.interstitial.adUnitID = @"ca-app-pub-9147160832662960/2548046734";
        GADRequest *request = [GADRequest request];
        // Requests test ads on simulators.
        [self.interstitial loadRequest:request];
        ...
    }
    return self;
}

游戏结束:

-(void)gameOver
{
    self.isGameOver = YES;
    ...

    if ([self.interstitial isReady]) {
        self.interstitial.delegate = self;
        [self.interstitial presentFromRootViewController:_viewController];
    }
   ...
}
scene.viewController = self.viewController;

这是需要添加到我的 GameScene 中的 initWithSize 的内容。 现在完美运行