Protocol Buffers is an instrument created by Google that allows you to define data structures in a specially designed definition language. Those structures are then compiled into classes that represent them in different programming languages (for instance Java).
When we create an application that collects data from a website, we don’t always have access to the API. So we can’t get data the easy way. We must manually parse HTML and select information from the entire document. In this article I will show you how do this by using two tools – Jsoup and SelectorGadget.
Retrofit is a type-safe REST client library released by Square. It provides us with an easy-to-use api with as little boilerplate code as possible, loose coupling between classes and programming to interfaces. Before I started using Retrofit I had been implementing my REST client logic with Volley which was not bad at all but there were some things that I wasn’t comfortable with