To understand this example, check out this post I wrote to explain it:
Applying Google's Android architecture with ObjectBox database
This is an example implementation of Google's architecture, found here: https://developer.android.com/topic/libraries/architecture/index.html
Similar to the above image, this example inclues a repository with a local database and remote APIs. But, the local database is using ObjectBox instead of Room. Also, the implementation of the network layer uses mock requests. Replacing it with real network requests with a library like Retrofit should be fairly straightforward though.
Here is what the example app looks like when it's running:
