I think you might do some separation code between apps. You can merge it in you settings.gradle to merge all apps/libraries in one project.

Here is the example

There is 4 additional code/library in 1 project which is app, xxxapi,xxxauth and xxxcommon.

So you can set your settings.gradle into something like :

include ':app', ':xxxapi', ':xxxauth', ':xxxcommon'

If you already set that code, you can use it in all your code in one project as well.

I want to create three related android apps (employee, Manager, Secretary) in clean-architecture and also share common classes (utils, Ui & etc.) among all three apps in order to reduce code duplication. Each project has multi-modular clean-architecture design. Would you guide me on how to connect these three projects to the shared classes, please? Is there any sample code for my case?

My project after using clean-architecture book by Alexandru Dumbravan: