Book Image

RxJava Essentials

By : Ivan Morgillo
Book Image

RxJava Essentials

By: Ivan Morgillo

Overview of this book

<p>RxJava—Reactive Extensions for the JVM—is a library for composing asynchronous and event-based programs using Observable sequences for the Java VM, which will help you beat Android platform limitations to create astonishing Android apps.</p> <p>Starting with some quick background information on the Rx .NET library, this book quickly moves on to your first example. You will understand Observables and learn to filter, transform, or merge them in detail. Next, you will learn how to get rid of Threads, AsyncTasks, and Handlers with Schedulers to create a smooth user experience. Develop an easy, ready-to-go approach to REST API communications and enrich your skills by working with new challenging examples.</p> <p>By the end of the book, you will have explored the reactive programming world and will have created your first Android app without having to think about threading, networking, concurrency, and collection management.</p> <p>The images have been taken from&nbsp;<a href="http://reactivex.io/" target="_blank">http://reactivex.io/</a> which is licensed under a Create Commons 3.0 Attribution license (<a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a>)</p>
Table of Contents (15 chapters)

Skip and SkipLast


The next figure shows how we can apply skip(2) to create a sequence that doesn't emit the first two elements of an Observable source but emits all the next items:

The skip() and skipLast() functions are the counterpart of take() and takeLast(). They get an integer N as a parameter and, basically, they suppress the first N or last N values emitted by an Observable. We can use it if we know that a sequence starts or ends with a control element that is not strictly useful for our purpose.

The next figure shows the counterpart scenario of the previous one: we are creating a new sequence that emits every item from the Observable source but skips the last two elements: