I have a multi-project (~10 modules) of which building takes about 20-30 seconds each time. When I press Run in Android Studio, I have to wait every time to rebuild the app,
Just try this first. It is my personal experience.
I had the same problem. What i had done is just permanently disable the antivirus (Mine was Avast Security 2015). Just after disabling the antivirus , thing gone well. the gradle finished successfully. From now within seconds the gradle is finishing ( Only taking 5-10 secs).