Book Image

Asynchronous Android Programming - Second Edition

By : Steve Liles
Book Image

Asynchronous Android Programming - Second Edition

By: Steve Liles

Overview of this book

Asynchronous programming has acquired immense importance in Android programming, especially when we want to make use of the number of independent processing units (cores) available on the most recent Android devices. With this guide in your hands you’ll be able to bring the power of Asynchronous programming to your own projects, and make your Android apps more powerful than ever before! To start with, we will discuss the details of the Android Process model and the Java Low Level Concurrent Framework, delivered by Android SDK. We will also guide you through the high-level Android-specific constructs available on the SDK: Handler, AsyncTask, and Loader. Next, we will discuss the creation of IntentServices, Bound Services and External Services, which can run in the background even when the user is not interacting with it. You will also discover AlarmManager and JobScheduler APIs, which are used to schedule and defer work without sacrificing the battery life. In a more advanced phase, you will create background tasks that are able to execute CPU-intensive tasks in a native code-making use of the Android NDK. You will be then guided through the process of interacting with remote services asynchronously using the HTTP protocol or Google GCM Platform. Using the EventBus library, we will also show how to use the Publish-Subscribe software pattern to simplify communication between the different Android application components by decoupling the event producer from event consumer. Finally, we will introduce RxJava, a popular asynchronous Java framework used to compose work in a concise and reactive way. Asynchronous Android will help you to build well-behaved applications with smooth responsive user interfaces that delight the users with speedy results and data that’s always fresh.
Table of Contents (19 chapters)
Asynchronous Android Programming Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
2
Performing Work with Looper, Handler, and HandlerThread
Index

Observing UI Events with RxJava


So far, we have been using RxJava to process and manipulate data streams, which simplified the development of asynchronous that require IO blocking operations that will hang the application for a while.

In this section, we want to explain how to use RxJava and reactive streams to simplify the handling of UI events generated from Android Widgets.

In our next example, we will present a list of Soccer Teams with an instant search result input field. As you type in the input field, the names available in the list will be filtered if the text that you typed matches the beginning of any soccer team on the list.

To achieve the result required, we will create a custom Observable that attaches a TextWatcher to the searching input field, listens for onTextChanged events, and emits a String event when the text changes.

The Observer will feed a reactive functional stream that will filter our list of teams in a Recycler View.

First, we will write a Custom Observable that registers...