manipulating the screen from subclass

Question

So I have created an android app and things are working alright.

In my main class I do a

new Game();

Now from the constructor of the game object I try and manipulate the screen, but it does not seem to do anything. Is it even possible?

public class Game extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.board);

    }
}