As the iAd framework notifies us when no adverts are available, we can use this delegate method to display an alternative banner, namely, a simple image.
iAd Demo Appfolder included with the book resources, locate the images
Banner.pngto the project navigator, that is, to the left of Xcode.
Unlike iAd Producer, Xcode doesn't automatically produce our low-resolution images from the high-resolution versions. ...