adView = new AdView(this);
adView.setAdSize(AdSize.BANNER);

AdSize customAdSize = new AdSize(250, 250);
PublisherAdView adView = new PublisherAdView(this);
adView.setAdSizes(customAdSize);

adView = new AdView(this);
// adView.setAdSizes(AdSize.BANNER);
adView.setAdSizes(AdSize.BANNER, new AdSize(120, 20), new AdSize(250, 250));

adView.setAdSize(AdSize.BANNER);

// Define custom AdSize of 250x250 for PublisherAdView

    AdSize customAdSize = new AdSize(250, 250);

    PublisherAdView adView = new PublisherAdView(this);

    adView.setAdSizes(customAdSize);