BaseActivity.java

public class BaseActivity extends FragmentActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        IronSource.init(this, AppConfig.IRONSOURCE_APP_KEY);
        ...
    }
}

MainActivity.java

public class MainActivity extends BaseActivity {

    IronSourceBannerLayout banner;
    LinearLayout adContainer;

    @Override
    protected void onResume() {
        super.onResume();
        initAd();
    }


    private void initAd() {
        if(banner==null) {
            banner = IronSource.createBanner(this, ISBannerSize.BANNER);
            FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.WRAP_CONTENT);
            adContainer = findViewById(R.id.banner_container);
            adContainer.addView(banner, 0, layoutParams);
        }
        banner.setBannerListener(new BannerListener() {
            @Override
            public void onBannerAdLoaded() {
                Log.oneLine("Called after a banner ad has been successfully loaded");
            }
            @Override
            public void onBannerAdLoadFailed(IronSourceError error) {
                Log.oneLine("// Called after a banner has attempted to load an ad but failed.: "+error.getErrorCode()+" "+error.getErrorMessage());
                runOnUiThread(() -> adContainer.removeAllViews());
            }
            @Override
            public void onBannerAdClicked() {
                Log.oneLine("// Called after a banner has been clicked.");
            }
            @Override
            public void onBannerAdScreenPresented() {
                Log.oneLine("// // Called when a banner is about to present a full screen content.");
            }
            @Override
            public void onBannerAdScreenDismissed() {
                Log.oneLine("// // Called after a full screen content has been dismissed.");
            }
            @Override
            public void onBannerAdLeftApplication() {
                Log.oneLine("// Called when a user would be taken out of the application context.");
            }
        });
        IronSource.loadBanner(banner);
       }