Unity Android Plugin Environment

I’ve recently begun work on android platform integrations into Crowman & Wolfboy. We’ve had a playable build of the game on Android for a while now, but some parts need more integration than others. I ended up having to write a java library for inclusion in the project.

This posed a new problem for us. All our iOS native plugins were included as objective-c files. Unity then copied those source files into the compiled project for XCode to build. This made it easy to include the source files in version control while keeping the build process simple. Android plugins aren’t so simple.

Unity requires android plugins be precompiled JAR files. I think it has something to do with Unity’s build process for android apps, but that doesn’t really matter. Those JAR files must be in the ‘Special Folder’ at the path Assets/Plugins/Android/. I wanted a way to easily keep the java source files in the same repository as the main project, but also keep the build process for the plugin simple.

The first thing I tried was putting the whole Eclipse workspace under versio control. That didn’t work because a lot of paths are saved as part of the workspace. The JDK path is different for different developers. The Android SDK path is different too.

I ended up making an Eclipse workspace adjacent to the main project folder. This workspace contained java projects as usual. Those java projects then used linked source folders. The source files were in a sub folder of the special android plugin folder. Each eclipse project then linked to its specific source folder. Then I can export the JAR to an external location (that being the special android plugin folder).

This setup will requires each developer configure their own eclipse workspace. Other than that the build process for a change to java code is easy as an export in Eclipse followed by a build in the Unity Editor. Not quite the ideal one-click-build, but java code shouldn’t be changed very often anyway.