Do you take off your sunglasses when talking to police? What specific official business are you referring to?
I have seen police specifically ask persons to remove their sunglasses prior to continuing a conversation during a traffic stop.
That's mainly to ID you better, but ok, you do take off your sunglasses.
Personally, I take off my sunglasses when I am conversing with anyone about anything. That is what I was taught as child. Look directly at the person to whom you are speaking.
Your last question is somewhat baffling in that police conduct, while on duty, official police business. If you care to further parse for clarification, traffic stops for instance.
You're inside your car while he's standing out in the sun. Is this really such a big issue for you that the officer takes basic care of his eyes?