请帮我弄清楚为什么下面注释掉的行会导致NoClassDefFoundError
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
RelativeLayout layout = new RelativeLayout(this);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
View gameView = initializeForView(new GraphicsView(), false);
// ERROR comes from these lines:
// AdView adView = new AdView(this, AdSize.BANNER, "a14fd65977f0c9f");
// adView.loadAd(new AdRequest());
RelativeLayout.LayoutParams adParams =
new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
adParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
adParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
layout.addView(gameView);
setContentView(layout);
}