Question. How to set background color and text style in icon generator?

[chitgoks]

I am looking at the equivalent in the ios lib for the android feature

iconFactory.setBackground(new ColorDrawable(Color.TRANSPARENT));
iconFactory.setTextAppearance(R.style.gdacs_bubble_text);

The xcode guide says .icon bucketIndex sets the background color of the bucket index. but no clue what these values should be. i am looking at removing the background actually, only the text should be visible.