title: Auto-reloading the admob interstitial ad?
body: <p>I'm using admob interstitial ad and it loads with onCreate</p>
  
  <p>so I can use it once but not twice. I have to load it again and then use it...</p>
  
  <p>I want to re load it right after it is shown, but there seems to be no such callback listener...</p>
  
  <p>How can I auto re-load the ad?</p>