Asynchronous Android Programming

394 Pages·2016·2.304 MB·English

by  Helder Vasconcelos

[ 1 ]
Asynchronous Android
Programming
Second Edition
Unlock the power of multi-core mobile devices to build
responsive and reactive Android applications
Helder Vasconcelos

BIRMINGHAM - MUMBAI
Asynchronous Android Programming
Second Edition
Copyright © 2016 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, without the prior written
permission of the publisher, except in the case of brief quotations embedded in
critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy
of the information presented. However, the information contained in this book is
sold without warranty, either express or implied. Neither the author, nor Packt
Publishing, and its dealers and distributors will be held liable for any damages
caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the
companies and products mentioned in this book by the appropriate use of capitals.
However, Packt Publishing cannot guarantee the accuracy of this information.
First published: July 2016
Production reference: 1260716
Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham B3 2PB, UK.
ISBN 978-1-78588-324-8
www.packtpub.com
Credits
Author Project Coordinator
Helder Vasconcelos Nidhi Joshi
Reviewer Proofreader
Gavin Matthews Safis Editing
Commissioning Editor Indexer
Edward Gordon Mariammal Chettiyar
Acquisition Editor Graphics
Indrajit Das Disha Haria
Content Development Editor Production Coordinator
Siddhesh Salvi Arvindkumar Gupta
Technical Editor Cover Work
Danish Shaikh Arvindkumar Gupta
Copy Editor
Vibha Shukla
About the Author
Helder Vasconcelos is a Portuguese Software Engineer based on Dublin,
Ireland, with more than 10 years of experience designing and developing
real-time/multithreaded Java and C++ applications for the telecommunications
and aviation industries. Apart from his day-to-day job, he occupies his spare
time building native Android applications for Bearstouch Software and
other third-party companies.
He graduated with a degree in Electronic and Telecommunications Engineering
from the University of Aveiro in January 2006. During his career, he has worked
as a Software Engineer for companies such as PT Inovação (Portugal), Airtel ATN
(Dublin, Ireland) and Axway (Dublin, Ireland). You can find Hélder on LinkedIn
at (https://ie.linkedin.com/in/heldervasc/en) or on his website at
(http://hvasconcelos.github.io).
I would like to sincerely thanks all technical reviewers, but especially
Gavin. I really appreciate your invaluable feedback and commit that
shaped the quality of the book. A special thanks to my awesome wife
Tania for encourage me when the lack of motivation was killing my
productivity. It would not have been possible without your precious
support. Thanks also to my parents and family for their awesome
effort in my education. Additionally, I would like to thank my
friends, colleagues, clients, and teachers for helping me to shape and
improve my skills and perspectives during my career.
About the Reviewer
Gavin Matthews is a veteran software engineer specializing in enterprise scale
B2B, MFT and EFSS systems.
www.PacktPub.com
eBooks, discount offers, and more
Did you know that Packt offers eBook versions of every book published, with PDF
and ePub files available? You can upgrade to the eBook version at www.PacktPub.
com and as a print book customer, you are entitled to a discount on the eBook copy.
Get in touch with us at [email protected] for more details.
At www.PacktPub.com, you can also read a collection of free technical articles, sign
up for a range of free newsletters and receive exclusive discounts and offers on Packt
books and eBooks.
TM
https://www2.packtpub.com/books/subscription/packtlib
Do you need instant solutions to your IT questions? PacktLib is Packt's online digital
book library. Here, you can search, access, and read Packt's entire library of books.
Why subscribe?
• Fully searchable across every book published by Packt
• Copy and paste, print, and bookmark content
• On demand and accessible via a web browser
Table of Contents
Preface vii
Chapter 1: Asynchronous Programming in Android 1
Android software stack 2
Dalvik runtime 2
ART runtime 3
Memory sharing and Zygote 4
Android process model 5
Process ranks 5
Process sandboxing 6
Android thread model 6
The main thread 7
The Application Not Responding (ANR) dialog 9
Maintaining responsiveness 10
Concurrency in Android 12
Correctness issues in concurrent programs 14
Liveness issues in concurrent programs 16
Thread coordination 16
Concurrent package constructs 19
Executor framework 20
Android primary building blocks 21
Activity concurrent issues 21
Manipulating the user interface 23
Service concurrent issues 25
Started services issues 25
Bound services issues 26
Service in a separate process 27
Broadcast receiver concurrent issues 28
Android concurrency constructs 28
Summary 29
[ i ]
Table of Contents
Chapter 2: Performing Work with Looper, Handler,
and HandlerThread 31
Understanding Looper 32
Understanding Handler 34
Sending work to a Looper 37
Scheduling work with post 39
Using Handler to defer work 40
Leaking implicit references 41
Leaking explicit references 43
Updating the UI with Handler 45
Canceling a pending Runnable 46
Scheduling work with send 47
Cancelling pending messages 50
Composition versus inheritance 52
Multithreading with Handler and ThreadHandler 53
Looper message dispatching debugging 58
Sending messages versus posting runnables 59
Applications of Handler and HandlerThread 59
Summary 60
Chapter 3: Exploring the AsyncTask 61
Introducing AsyncTask 62
Declaring AsyncTask types 65
Executing AsyncTasks 67
Providing indeterministic progress feedback 69
Providing deterministic progress feedback 72
Canceling an AsyncTask 75
AsyncTask Execution State 78
Handling exceptions 79
Controlling the level of concurrency 81
Common AsyncTask issues 84
Fragmentation issues 84
Memory leaks 85
Activity lifecycle issues 85
Handling lifecycle issues with early cancellation 86
Handling lifecycle issues with retained headless fragments 87
Applications of AsyncTask 92
Summary 93
Chapter 4: Exploring the Loader 95
Introducing Loaders 96
Loader API 96
Loader 97
[ ii ]
Table of Contents
Loader Manager 98
LoaderManager.LoaderCallbacks 99
Loader lifecycle 100
Loading data with Loader 101
Building responsive apps with AsyncTaskLoader 107
Building responsive apps with CursorLoader 116
Combining Loaders 119
Applications of Loader 125
Summary 125
Chapter 5: Interacting with Services 127
Introducing Service 128
Started service 131
Building responsive apps with IntentService 136
Handling results 139
Posting results with PendingIntent 139
Posting results as system notifications 142
Applications of IntentService 143
HTTP uploads with IntentService 144
Reporting progress 146
Bound Service 149
Communicating with a Local Service 150
Broadcasting results with intents 158
Detecting unhandled broadcasts 160
Applications of Services 163
Summary 164
Chapter 6: Scheduling Work with AlarmManager 165
Introducing AlarmManager 166
Scheduling alarms with AlarmManager 167
Setting alarms in recent Android versions 169
Testing your alarms in Doze Mode 172
Setting a Window alarm 173
Debugging AlarmManager alarms 173
Canceling alarms 175
Scheduling repeating alarms 176
Scheduling an alarm clock 178
Handling alarms 179
Handling alarms with Activities 180
Handling alarms with BroadcastReceiver 181
Working with BroadcastReceiver 183
Asynchronous work with goAsync 186
[ iii ]