I have an app with Admob ads on it but I find that when I use it the ad almost never refreshes because I don\'t change activities, instead I just update a text view when but
Old API version:
AdView.requestFreshAd();
New API version:
AdView.loadAd(new AdRequest());
Also, you can simply set a refresh interval with the refreshInterval
attribute on the AdView element in your layout XML file. Or you can set the refresh interval for the ads in your app via your account settings on the AdMob website.
Documentation: http://code.google.com/mobile/ads/docs/android/intermediate.html#adrefresh