Android Studio: Add jar as library?

I’ve been struggling with the same thing for many hours, trying to get the Gson jar to work no less. I finally cracked it – here are the steps I took:

1. Put the Gson jar (in my case, gson-2.2.4.jar) into the libs folder
2. Right click it and hit ‘Add as library’
3. Ensure that compile files('libs/gson-2.2.4.jar') is in your build.gradle file
4. Do a clean build (you can probably do this fine in Android Studio, but to make sure I navigated in a terminal to the root folder of my app and typed gradlew clean. I’m on Mac OS X, the command might be different on your system

After I did the above three, it started working fine. I think the ‘Add as library’ step was the one I’d previously missed, and it didn’t work until I cleaned it either.

[Edit – added the build.gradle step which is also necessary as others have pointed out]

Source: http://stackoverflow.com/