public void ShowRewardedVideo() { if (!CrossAdMob.Current.IsEnabled) { return; } if (_rewardedAd.IsReady) { var window = UIApplication.SharedApplication.KeyWindow; var vc = window.RootViewController; while (vc.PresentedViewController != null) { vc = vc.PresentedViewController; } _rewardedAd.Present(vc, this); } }