Xamarin Google本地广告iOS

Question

我正在尝试在Xamarin中实现本地广告，它可以与Android一起使用，但我对iOS有问题 这是我的代码，

public class AdMobNativeAdRenderer : ViewRenderer<Controls.NativeAdView, UnifiedNativeAdView>, IAdLoaderDelegate, IUnifiedNativeAdDelegate, IUnifiedNativeAdLoaderDelegate, IVideoControllerDelegate

    {

        
        public UnifiedNativeAdView nativeAdView = null;
        public void DidReceiveUnifiedNativeAd(AdLoader adLoader, UnifiedNativeAd nativeAd)
        {

            // A unified native ad has loaded, and can be displayed.
            nativeAd.Delegate = this;
            //  The headline and mediaContent are guaranteed to be present in every native ad.
            nativeAdView.NativeAd = nativeAd;
            if (nativeAdView.HeadlineView==null)
            {
                nativeAdView.HeadlineView= new UILabel();
            }
            (nativeAdView.HeadlineView as UILabel).Text = nativeAd.Headline;
            if (nativeAdView.MediaView == null) {
                nativeAdView.MediaView = new MediaView();
             }
            if (nativeAdView.MediaView.MediaContent == null)
            {
                nativeAdView.MediaView.MediaContent = new MediaContent();
            }
            nativeAdView.MediaView.MediaContent = nativeAd.MediaContent;
            nativeAdView.MediaView.ContentMode = UIViewContentMode.ScaleAspectFill;
            if (nativeAdView.BodyView==null)
            {
                nativeAdView.BodyView = new UILabel();
            }
            (nativeAdView.BodyView as UILabel).Text = nativeAd.Body;
            nativeAdView.BodyView.Hidden = nativeAd.Body == null;
            if (nativeAdView.CallToActionView==null)
            {
                nativeAdView.CallToActionView = new UIButton();
            }
       
            (nativeAdView.CallToActionView as UIButton).SetTitle(nativeAd.CallToAction,UIControlState.Normal);
            nativeAdView.CallToActionView.Hidden = nativeAd.CallToAction == null;

            if (nativeAdView.IconView==null)
            {
                nativeAdView.IconView = new UIImageView();
            }
            (nativeAdView.IconView as UIImageView).Image = nativeAd.Icon.Image;
            nativeAdView.IconView.Hidden = nativeAd.Icon == null;
            if (nativeAdView.StoreView==null)
            {
                nativeAdView.StoreView = new UILabel();
            }
            (nativeAdView.StoreView as UILabel).Text = nativeAd.Store;
            nativeAdView.StoreView.Hidden = nativeAd.Store == null;

            if (nativeAdView.PriceView==null)
            {
                nativeAdView.PriceView = new UILabel();
            }
            (nativeAdView.PriceView as UILabel).Text = nativeAd.Price;

            nativeAdView.PriceView.Hidden = nativeAd.Price == null;
            if (nativeAdView.AdvertiserView==null)
            {
                nativeAdView.AdvertiserView = new UILabel();
            }
            if (nativeAdView.StoreView==null)
            {
                nativeAdView.StoreView = new UILabel();
            }
            (nativeAdView.StoreView as UILabel).Text = nativeAd.Store;


            (nativeAdView.AdvertiserView as UILabel).Text = nativeAd.Advertiser;
            nativeAdView.AdvertiserView.Hidden = nativeAd.Advertiser == null;
            nativeAdView.CallToActionView.UserInteractionEnabled = false;
            nativeAdView.NativeAd = nativeAd;
            try
            {
               nativeAdView.BackgroundColor = UIColor.Green;
                SetNativeControl(nativeAdView);
                
            }
            catch (Exception ex)
            {

                Debug.WriteLine(ex.Message);
            }
            
        }

        
        [Export("adLoaderDidFinishLoading:")]
        void DidFinishLoading(AdLoader adLoader)
        {
            // The adLoader has finished loading ads, and a new request can be sent.
        }

        public void DidFailToReceiveAd(AdLoader adLoader, RequestError error)
        {

        }
        protected override void OnElementChanged(ElementChangedEventArgs<Controls.NativeAdView> e)
        {
            base.OnElementChanged(e);
            try
            {
                if (e.OldElement != null)
                {
                    try
                    {
                        e.OldElement.Content=null;
                    }
                    catch (Exception)
                    {


                    }

                    
                    SetNativeControl(nativeAdView);
                }

                if (e.NewElement != null)
                {
                    if (Control == null)
                    {
                        // Instantiate the native control and assign it to the Control property with
                        CreateAdView();
                        try
                        {
                            e.NewElement.Content = null;
                        }
                        catch (Exception)
                        {


                        }

                        SetNativeControl(nativeAdView);

                    }
                }
            }
            catch (Exception ex)
            {

                Debug.WriteLine(ex.Message);
            }

        }
        AdLoader  adLoader;
        private void CreateAdView()
        {

            //if (Element == null) return;
            var multipleAdsOptions = new MultipleAdsAdLoaderOptions { NumberOfAds = 1 };
            adLoader = new AdLoader("ca-app-pub-3940256099942544/3986624511", GetVisibleViewController(), new[] { AdLoaderType.UnifiedNative }, new[] { multipleAdsOptions })
            {
                Delegate = this
            };

            var request = Request.GetDefaultRequest();
            request.TestDevices = new string[] { Request.SimulatorId };



            if (nativeAdView == null)
            {
                nativeAdView = new UnifiedNativeAdView();
            };

            try
            {
                adLoader.LoadRequest(request);

            }
            catch (Exception e)
            {
                Debug.WriteLine(e.Message);
            }

            Debug.WriteLine("Loading: " + adLoader.IsLoading);
        }
        private UIViewController GetVisibleViewController()
        {
            var windows = UIApplication.SharedApplication.Windows;
            foreach (var window in windows)
            {
                if (window.RootViewController != null)
                {
                    return window.RootViewController;
                }
            }
            return null;
        }

    }

每件事都可以按预期工作，我会收到广告和事件didreceiveunifiednativead火灾，但是我得到了一个空的广告，尽管当我调试代码时，我看到广告的内容不是空的，并且控制颜色是绿色的，所以控件已加载，但是为什么它不显示广告内容 请任何人帮助解决这个问题