I have written the code for adding interstitial ads from admob to my app's menu activity as per https://developers.google.com/mobile-ads-sdk/docs/admob/advanced. I have added PERMISSIONS and configchanges in Manifest too. I am getting error in the lines mentioned below:
`
interstitial = new InterstitialAd(this); // Error: The constructor InterstitialAd(MenuActivity) is undefined
interstitial.setAdUnitId("lajdID"); // Error: The method setAdUnitId(String) is undefined for the type InterstitialAd
// Create ad request.
AdRequest adRequest = new AdRequest.Builder().build(); //AdRequest.Builder cannot be resolved to a type
// Begin loading your interstitial.
interstitial.loadAd(adRequest);
`