Android: Device is a 10" tablet or 7" tablet

DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int widthPixels = metrics.widthPixels;
int heightPixels = metrics.heightPixels;
float scaleFactor = metrics.density;
float widthDp = widthPixels / scaleFactor;
float heightDp = heightPixels / scaleFactor;
float smallestWidth = Math.min(widthDp, heightDp);
if (smallestWidth > 720) {
    //Device is a 10" tablet    adView.setAdSize(new AdSize(770, 80));
} else if (smallestWidth > 600) {
    //Device is a 7" tablet    adView.setAdSize(new AdSize(570, 80));
}