Hi,
I am not sure if this helps but perhaps you can use the
alternatingRowColors : bool
property of QAbstractItemView - if alternating is what you want to do.
I think (I may be wrong) you might have to think more in terms of "change the model" than "change the display". I, myself, have yet to really understand the "delegate" thing, but this helped me once in a similar thing. Sorry to be so unprecise, this is the best I can do.
SeDi