@protocol GADNativeExpressAdViewDelegate <NSObject>
Delegate methods for receiving GADNativeExpressAdView state change messages such as ad request status and ad click lifecycle.
Tells the delegate that the native express ad view successfully received an ad. The delegate may want to add the native express ad view to the view hierarchy if it hasn’t been added yet.
Tells the delegate that an ad request failed. The failure is normally due to network connectivity or ad availablility (i.e., no fill).
optional func nativeExpressAdView(_ nativeExpressAdView: GADNativeExpressAdView!, didFailToReceiveAdWithError error: GADRequestError!)
Tells the delegate that a full screen view will be presented in response to the user clicking on an ad. The delegate may want to pause animations and time sensitive interactions.
Tells the delegate that the full screen view has been dismissed. The delegate should restart anything paused while handling adViewWillPresentScreen:.
Tells the delegate that the user click will open another app, backgrounding the current application. The standard UIApplicationDelegate methods, like applicationDidEnterBackground:, are called immediately before this method is called.