Android Programming: The Big Nerd Ranch Guide, 5th Edition

Networking Basics with Retrofit

Although it is not developed by Google, Retrofit is the de facto official way to communicate with an HTTP API on Android. Retrofit is an open-source library created and maintained by Square (square.github.io/​retrofit). It is highly configurable and extendable, allowing you to easily and safely communicate with a remote web server. It is organized into components that serve a specific purpose, and you can swap out individual components as you need.

Retrofit is meant to define the contracts for many different types of network requests. Similar to using the Room database library, you write an interface with annotated instance methods, and Retrofit creates the implementation. Under the hood, Retrofit’s ...