Implementing MVVM design pattern without RX and Dependency Injection.
In this example, you can see how to call REST API with retrofit and work with Room Database in the MVVM design pattern. The app uses REST API to log in and fetch data while using a local database using the Room library to save user favs on the user's device. The app uses https://fakestoreapi.com/ API to log in and fetch data. You can download and install the APK from the release section.
To keep everything as simple as possible, I didn't use any dependency injection tool and ReactiveX programming.