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)

The app structure


We are not using any MVC, MVP, or MVVM paradigms because that is not the purpose of this book, so our Activity class will contain all the logic we need to create and show our list of users.

Creating the Activity class

We will set up SwipeRefreshLayout and RecyclerView in our onCreate() method; we have a refreshList() method to handle the fetching and showing of our list of users and showRefreshing() to manage the ProgressBar and RecyclerView visibility.

Our refreshList() function looks like this:

private void refreshList() {
    showRefresh(true);
    mSeApiManager.getMostPopularSOusers(10)
            .subscribe(users -> {
                showRefresh(false);
                mAdapter.updateUsers(users);
            }, error -> {
                App.L.error(error.toString());
                showRefresh(false);
            });
}

We show ProgressBar, and observe the list of users from the StackExchange API manager. The moment the list comes in, we show it and update the...