打开应用程序时创建应用程序，立即加载

public class MyApplication extends Application {
public InterstitialAd mInterstitialAd;
private AppOpenManager appOpenAdManager;
private Activity currentActivity;
private int check = 0;
public AdLoader adLoader;
@Override
public void onCreate() {
    super.onCreate();
    MobileAds.initialize(
            this,
            new OnInitializationCompleteListener() {
                @Override
                public void onInitializationComplete(
                        @NonNull InitializationStatus initializationStatus) {
                }
            });
    appOpenAdManager = new AppOpenManager();
    loadInterstitial(AD_UNIT_ID_INTERSTITIAL_ADS);
}

public void loadInterstitial(String id) {
    AdRequest adRequest = new AdRequest.Builder().build();
    InterstitialAd.load(
            this,
            id,
            adRequest,
            new InterstitialAdLoadCallback() {
                @Override
                public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
                    mInterstitialAd = interstitialAd;
                    interstitialAd.setFullScreenContentCallback(
                            new FullScreenContentCallback() {
                                @Override
                                public void onAdDismissedFullScreenContent() {
                                    mInterstitialAd = null;
                                }

                                @Override
                                public void onAdFailedToShowFullScreenContent(AdError adError) {
                                    // Called when fullscreen content failed to show.
                                    // Make sure to set your reference to null so you don't
                                    // show it a second time.
                                    mInterstitialAd = null;
                                }

                                @Override
                                public void onAdShowedFullScreenContent() {
                                }
                            });
                }

                @Override
                public void onAdFailedToLoad(@NonNull LoadAdError loadAdError) {
                    mInterstitialAd = null;
                }
            });
}

}然后创建类检查加载和打开应用程序时发生的异常

public class LoadInterstitialAds {
private static LoadInterstitialAds instance;
private InterstitialAd mInterstitialAd;

public static LoadInterstitialAds getInstance() {
    if (instance == null) {
        return new LoadInterstitialAds();
    }
    return instance;
}

public void openAdsThenOpenActivity(Activity activity, InterstitialAdsListener listener) {
    Application application = activity.getApplication();
    if (application instanceof MyApplication) {
        LoadInterstitialAds.this.mInterstitialAd = ((MyApplication) application).mInterstitialAd;
        if (LoadInterstitialAds.this.mInterstitialAd != null) {
            LoadInterstitialAds.this.mInterstitialAd.show(activity);
            LoadInterstitialAds.this.mInterstitialAd.setFullScreenContentCallback(new FullScreenContentCallback() {

                @Override
                public void onAdDismissedFullScreenContent() {
                    listener.onStartActivity();
                    ((MyApplication) application).loadInterstitial(AD_UNIT_ID_INTERSTITIAL_ADS);
                }

                @Override
                public void onAdFailedToShowFullScreenContent(@NonNull AdError adError) {
                    ((MyApplication) application).loadInterstitial(AD_UNIT_ID_INTERSTITIAL_ADS);
                    listener.onStartActivity();
                }

            });
        } else {
            ((MyApplication) application).loadInterstitial(AD_UNIT_ID_INTERSTITIAL_ADS);
            listener.onStartActivity();
        }
    }
}

}创建接口侦听器以方便调用

public interface InterstitialAdsListener {
void onStartActivity();

}，最后，在您想要显示的任何位置运行此代码

LoadInterstitialAds loadInterstitialAds = LoadInterstitialAds.getInstance();
        loadInterstitialAds.openAdsThenOpenActivity(getActivity(), ()->{
           // your process
        });