I have a simple android project with test cases.
ProjNameProject
--build.gradle
--ProjName
----build.gradle
I see that by default android\'
Emma support is planned to be released soon within the new Android build system : http://tools.android.com/tech-docs/new-build-system/roadmap
Up to now there is no official way to run emma with android via gradle. I guess instrumenting can be achieved pretty easily but then, you will miss a way to tell Android to run tests with coverage on. Moreover, there is currently no way (to the best of my knowledge) to pull down emma runtime coverage data from the device.
This project can interest you : https://github.com/stephanenicolas/Quality-Tools-for-Android. It will be updated as soon as emma will make it into Android Gradle plugin.
----UPDATE
This plugin has no chance to work with Android has it uses the Java plugin which is incompatible with Android plugin.