A full page ad experience at natural transition points such as a page change, an app launch, or a game level load. Interstitials use a close button that removes the ad from the user's experience.

Sample code:

 public class MyActivity extends Activity {
     private InterstitialAd interstitialAd;
     private Button nextLevelButton;
     private TextView textView;

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         // Create a full screen content callback.
         FullScreenContentCallback fullScreenContentCallback = new FullScreenContentCallback() {
             @@Override
             public void onAdDismissedFullScreenContent() {
                interstitialAd = null;
                // Proceed to the next level.
                goToNextLevel();
             }
         };

         // Load an interstitial ad. When a natural transition in the app occurs (such as a level
         // ending in a game), show the interstitial. In this simple example, the press of a
         // button is used instead.
         //
         // If the button is clicked before the interstitial is loaded, the user should proceed to
         // the next part of the app (in this case, the next level).
         //
         // If the interstitial is finished loading, the user will view the interstitial before
         // proceeding.
         InterstitialAd.load(
             this,
             "myAdUnitId",
             new AdRequest.Builder().build(),
             new InterstitialAdLoadCallback() {
                 @Override
                 public void onAdLoaded(@NonNull InterstitialAd ad) {
                     interstitialAd = ad;
                     interstitialAd.setFullScreenContentCallback(fullScreenContentCallback);
                 }

                 @@Override
                 public void onAdFailedToLoad(@NonNull LoadAdError adError) {
                     // Code to be executed when an ad request fails.
                 }
             });

         // Create the button to go to the next level.
         nextLevelButton = new Button(this);
         nextLevelButton.setText("Next Level");
         nextLevelButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
                 // Show the interstitial if it is ready. Otherwise, proceed to the next level
                 // without ever showing it.
                 if (interstitialAd != null) {
                     interstitialAd.show(MyActivity.this);
                 } else {
                     // Proceed to the next level.
                     goToNextLevel();
                 }
             }
         });

         // Add the next level button to the layout.
         LinearLayout layout = new LinearLayout(this);
         layout.setOrientation(LinearLayout.VERTICAL);
         layout.addView(nextLevelButton);

         // Create a TextView to display the current level.
         textView = new TextView(this);
         textView.setText("Level 1");
         layout.addView(textView);

         setContentView(layout);
     }

     public void goToNextLevel() {
         // Show the next level, and disable the next level button since there are no more levels.
         nextLevelButton.setEnabled(false);
         textView.setText("Level 2");
     }
 }