Using part of an Android app in a non-Android Java project

Question

I'm working on a server backend component for an app, and one goal is to log all the messages transmitted through the app (using MQTT). To do this, I wanted to use the app as a library of sorts so that I could use the objects defined within to parse the messages coming through, since none of the messages will be transmitted as standard types. I'm using IntelliJ for the Java development, and Android Studio for the Android development. Is this possible? I was previously able to import the code as a module, which let me use the types defined within, but when I went to build the project it tried to build the Android code as well and failed because IntelliJ hadn't set up Android dependencies. Should I try and set the Android SDK as a dependency in the app module, and then build? Or am I approaching this the wrong way? (if it's even possible) I understand that there are also Library projects which looks like a possible solution, it would just require re-factoring all the applicable code out to a different project and I was hoping that wouldn't be necessary.

Answer 1

Trying to import the entire Android app as a library into a different codebase probably isn't going to work; you don't want a non-Android app to have all that Android code linked in, and with resources and the whole environment it will be tough to get it to compile at all.

A better approach would be to take all of the code that needs to work cross-platform and distill it into a plain Java library that you can include in multiple contexts. On the Android side you could include it as a plain Java library project, or compile it to a jar and include the jar.