ok , there is probably no alternative that uses the API , unless maybe i’ve forgetting anything.
i can however use dimming , which is cool too, as written here:
WindowManager.LayoutParams lp = dialog.getWindow().getAttributes();
lp.dimAmount=0.0f;
dialog.getWindow().setAttributes(lp);
dialog.getWindow().addFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND);