As from previous post for army recruit, if two times or more misdemeanor charges, regardless of disposition or not, constitute questionable moral character.
But don't worry. By law, you are still eligble for green card. Just as Xiaobaitu said, attach a letter to explain all the two cases. You should also send them the certified dispostion proofs from the court to USCIS with your I-485 application. You will be fine. But maybe you probably will stuck for a longer fbi name check, which is really headache.