I have just upgraded (i.e., installed a full new version) my Android Studio from 1.5 to 2.0. The upgrade seemed to go smoothly, but I am having trouble with my project when
I had a similar problem. I was trying to build one of the media samples. I tried to use gradle 2.0.0 as you suggested but it didn't work. Got me on the right track though. gradle 2.1.0, along with deactivating offline mode got it to work.