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Asynchronous Android Programming
Asynchronous Android Programming

Asynchronous Android Programming: Unlock the power of multi-core mobile devices to build responsive and reactive Android applications , Second Edition

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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Full star icon 5 (3 Ratings)
Paperback Jul 2016 394 pages 2nd Edition
eBook
€8.99 €32.99
Paperback
€41.99
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Arrow left icon
Profile Icon Vasconcelos Profile Icon Liles
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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Full star icon 5 (3 Ratings)
Paperback Jul 2016 394 pages 2nd Edition
eBook
€8.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€8.99 €32.99
Paperback
€41.99
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Renews at €18.99p/m

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Asynchronous Android Programming

Chapter 2. Performing Work with Looper, Handler, and HandlerThread

In the previous chapter, you were introduced to the most basic concurrent issues that a developer might face while developing a responsive and concurrent Android application. As the most interactable items run on the main thread, it is crucial to coordinate the backgrounds code to handle the work without any UI stuttering that compromises the user experience.

In this chapter, we will meet some of most fundamental constructs used on Android systems to perform tasks and schedule on a main thread or an ordinary background thread created by the developer to perform and schedule tasks long-running operations.

We will cover the following topics:

  • Understanding Looper
  • Understanding Handler
  • Sending work to Looper
  • Scheduling work with post
  • Using Handler to defer work
  • Leaking implicit references
  • Leaking explicit references
  • Updating the UI with Handler
  • Canceling pending messages
  • Multithreading with Handler and HandlerThread
  • Applications...

Understanding Looper

Before we can understand Looper, we need to understand where it gets its name from.

Note

A loop is a group of instructions that are repeated continually until a termination condition is met.

Following this definition, Android's Looper executes on a thread that has a MessageQueue, executes a continuous loop waiting for work, and blocks when there is no work pending. When work is submitted to its queue, it dispatches it to the target Handler defined explicitly on the Message object.

Note

A message is a notification object containing a description and arbitrary data object that can be sent to a Handler.

The Looper on Android is an implementation of a common UI programming concept known as an event loop. Later, at the end of this processing sequence, the Handler will process the Message and execute your domain logic in order to solve an application user problem.

The Looper sequence on Android follows these steps:

  1. Wait until a Message is retrieved from its MessageQueue
  2. If logging...

Summary

In this chapter, we learned how to use Handler to queue work for the main thread and how to use Looper to build up a queueing infrastructure for our own Thread.

We saw the different ways in which we can define work with Handler: arbitrary work defined at the call site with Runnable or predefined work implemented in the Handler itself and triggered by message-sending.

In the meantime, we learned how to defer work properly without leaking memory on the way.

We learned how to use Handler in a multithreaded application to pass work and results back and forth between cooperating threads, performing blocking operations on an ordinary background thread and communicating the results back to the main thread to update the user interface.

In the next chapter, we'll start to build responsive applications by applying the AsyncTask instance to execute work in the background using pools of threads and returning progress updates and results to the main thread.

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Key benefits

  • Construct scalable and performant applications to take advantage of multi-thread asynchronous techniques
  • Explore the high-level Android asynchronous constructs available on the Android SDK
  • Choose the most appropriate asynchronous technique to implement your next outstanding feature

Description

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.

Who is this book for?

This book is for Android developers who want to learn how to build multithreaded and reliable Android applications using high-level and advanced asynchronous techniques and concepts. No prior knowledge of concurrent and asynchronous programming is required. This book will also be great for Java experts who are new to Android. Whether you are a beginner at Android development or a seasoned Android programmer, this book will guide you through the most basic and advanced asynchronous constructs used in Android programming.

What you will learn

  • Get familiar with the android process model and low-level concurrent constructs delivered by the Android SDK
  • Use AsyncTask and loader framework to load data in the background, delivering progress results in the meantime
  • Create services that interact with your activity without compromising the UI rendering
  • Learn the working of Android concurrency on the Native Layer
  • Interact with nearby devices over Bluetooth and WiFi communications channels
  • Create and compose tasks with RxJava to execute complex asynchronous work in a predictable way
  • Get accustomed to the use of the Android Loader construct to deliver up-to-date results

Product Details

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Publication date, Length, Edition, Language, ISBN-13
Publication date : Jul 29, 2016
Length: 394 pages
Edition : 2nd
Language : English
ISBN-13 : 9781785883248
Vendor :
Google
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Product Details

Publication date : Jul 29, 2016
Length: 394 pages
Edition : 2nd
Language : English
ISBN-13 : 9781785883248
Vendor :
Google
Category :
Languages :
Tools :

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Table of Contents

13 Chapters
1. Asynchronous Programming in Android Chevron down icon Chevron up icon
2. Performing Work with Looper, Handler, and HandlerThread Chevron down icon Chevron up icon
3. Exploring the AsyncTask Chevron down icon Chevron up icon
4. Exploring the Loader Chevron down icon Chevron up icon
5. Interacting with Services Chevron down icon Chevron up icon
6. Scheduling Work with AlarmManager Chevron down icon Chevron up icon
7. Exploring the JobScheduler API Chevron down icon Chevron up icon
8. Interacting with the Network Chevron down icon Chevron up icon
9. Asynchronous Work on the Native Layer Chevron down icon Chevron up icon
10. Network Interactions with GCM Chevron down icon Chevron up icon
11. Exploring Bus-based Communications Chevron down icon Chevron up icon
12. Asynchronous Programing with RxJava Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Full star icon 5
(3 Ratings)
5 star 100%
4 star 0%
3 star 0%
2 star 0%
1 star 0%
Daryl Ducharme Mar 18, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Java Concurrency in Practice is a great book for theory on concurrency in a java context but this book gets to some best practices while in Android. There's usually no need to write your own solution when these are already part of the framework and battle tested. The first several sections are very important to understand if you are going to make a robust Android application.
Amazon Verified review Amazon
Amazon Customer Feb 22, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
I amazed with the level of detail found in this practical book. I definitely recommend it to every who is serious about software development.
Amazon Verified review Amazon
Victor Johns Dec 21, 2016
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The great thing about Android is that it is pretty much a self contained ecosystem. The bad thing about Android is that it is really hard to get your head around some of the more detailed nuances of the underlying OS. This book does a great job of delving into how the Android OS features can be taken advantage of, esp by today's multicore processors.Having come from a Linux background, I was finding it hard to get a resource that would allow me to understand exactly how the threading model of Android works. This book proved to be a great help
Amazon Verified review Amazon
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