Normally door frames first and tile or timber floor after... think it also gives the better finish. In case of tiles you can grout the line up to the frame
Floors first makes it easy for the door frame fitters, but really it should be frames first, then floor. frame fitters will need to know the floor thickness you plan on installing to ensure the doors are hung at the right height and there's enough clearance for the doors to open.
Floors first would make if a lot mor difficult to change the floors in the future without damaging the door frames.
Leo
Would have to say i totally agree with everyone who says to do the floors first. It's a much neater job especially in the case of timber floors where you have to leave room for expansion.
Just done this in my own house and am a tiler by trade.