Learning RxJava - Second Edition

Observable and Observer

We already got a glimpse into Observable and how it works in Chapter 1, Thinking Reactively. You probably have many questions on how exactly it operates and what practical implications it brings to code.

This chapter will provide a foundation for the understanding of Observable, as well as the critical relationship it has with Observer. We will also cover several ways to create an Observable and how to use its operators. To make the rest of the book flow smoothly, we will also cover all critical nuances head-on to build a solid foundation, so that you do not have surprises later.

Here is what we will cover in this chapter:

• The Observable class
• The Observer interface
• Observable factories
• Single, Completable, and ...