for (int y = 0; y < 3; y++) {

                levels.row();

                for (int x = 0; x < 4; x++) {

                    button.addListener(levelClickListener);
                }
            }

	public ClickListener levelClickListener = new ClickListener() {
	    @Override
	    public void clicked (InputEvent event, float x, float y) {
		//load level
	    }
	};