GradientDrawable활용 button shape selector 코드 처리

public static void setButtonBackground(Button btn, int normal_color, int press_color) {
    StateListDrawable res = new StateListDrawable();
    res.addState(new int[]{android.R.attr.state_pressed}, setGradientColors(normal_color));
    res.addState(new int[]{}, setGradientColors(press_color));
    btn.setBackground(res);
}

public static GradientDrawable setGradientColors(int color) {
    GradientDrawable gradient = new GradientDrawable();
    gradient.setShape(GradientDrawable.RECTANGLE);
    gradient.setColor(color);
    gradient.setCornerRadius(120.f);
    return gradient;
}