ebleh if you want to you can do this too. i will send you a picture for this if needed. Everytime a level ends and the level screen opens you can check an array for the number of points there are for each level and assign star according to that. make sure that each level button is a widget of its own. that way each level button widget can get the information on being constructed and just change the opacity of stars.
btw i didnt read anything up there, but i think i didnt say the exact same thing. sorry if i did.