Android Programming

434 Pages·2013·11.24 MB·English

by  Hellman, Erik

™
Android
Programming
Pushing the Limits
Erik Hellman
This edition first published 2014
© 2014 Erik Hellman
Registered office
John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom
For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright
material in this book please see our website at www.wiley.com.
The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents
Act 1988.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988,
without the prior permission of the publisher.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.
This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the
understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is
required, the services of a competent professional should be sought.
Trademarks: Wiley and the Wiley logo are trademarks or registered trademarks of John Wiley and Sons, Inc. and/ or its affiliates in the United
States and/or other countries, and may not be used without written permission. Android is a trademark of Google, Inc. All other trademarks
are the property of their respective owners. John Wiley & Sons, Ltd. is not associated with any product or vendor mentioned in the book.
A catalogue record for this book is available from the British Library.
ISBN 978-1-118-71737-0 (paperback); ISBN 978-1-118-71730-1 (ePDF); 978-1-118-71735-6 (ePub)
Set in 9.5 pt Myriad Pro by Indianapolis Composition Services
Printed in the United States by Bind-Rite
Dedication
This book is dedicated to my amazing dad, Ingemar Hellman, who taught me programming when I was
nine years old. None of this would have been possible if it weren’t for all the amazing things he taught me.
Erik Hellman,
Second generation software developer
Publisher’s Acknowledgements
Some of the people who helped bring this book to market include the following:
Editorial and Production
VP Consumer and Technology Publishing Director: Michelle Leete
Associate Director–Book Content Management: Martin Tribe
Associate Publisher: Chris Webb
Project Editor: M. Faunette Johnston
Copy Editor: Melba Hopper
Technical Editor: Erik Westenius
Editorial Manager: Jodi Jensen
Senior Project Editor: Sara Shlaer
Editorial Assistant: Annie Sullivan
Marketing
Associate Marketing Director: Louise Breinholt
Marketing Manager: Lorna Mein
Senior Marketing Executive: Kate Parrett
Marketing Assistant: Polly Thomas
Composition Services
Compositor: Jennifer Goldsmith, Andrea Hornberger
Proofreader: Wordsmith Editorial
Indexer: Potomac Indexing, LLC
About the Author
Erik Hellman grew up in the small town of Borlänge in the middle of Sweden and currently lives in the city
of Malmö with his wife. From an early age he showed a great interest in all kinds of technology, much thanks
to his father. This interest has carried on over the years and he likes to spend time tinkering with all kinds of
technology, be it hardware or software.
Erik currently works as a developer consultant at Factor10. He previously worked for Sony Mobile as one of the
lead architects for their Android development and later as a research engineer where he participated in the
development of the next generation of mobile solutions from Sony.
Erik has a lifetime of experience with software development and programming. His father taught him how to
write code in Turbo Pascal at the age of nine, as well as how to design relational databases in Oracle 3 on his
old IBM AT 286. Much later, Erik studied Software Engineering at Blekinge Institute of Technology where he also
worked as an assistant teacher in various software engineering courses.
Erik can often be found at various developer conferences where he likes to speak about cutting-edge software
technologies. You can also find out more about Erik and his other hobbies at his blog (http://blog.hellsoft.se) or
follow him on Google+ (http://gplus.to/ErikHellman) or Facebook (https://www.facebook.com/ErikHellman).
Acknowledgements
First of all, I’d like to thank my wife Kaisa-Leena. Without her love, support, and infinite patience with me during
the writing of this book, this book would never have been finished.
A big thank you goes out to all my friends and former colleagues at Sony Mobile. Almost everything I’ve learned
about Android and mobile technologies came from my years working with all of you. I’m extremely proud to
have been part of the team that built the Xperia series of devices. A special thank you to my former boss, Henrik
Bengtsson, and his team at the Sony Mobile Research in Lund.
Finally, I’d like to thank my editors; Faunette, Melba, Erik, and all the people working at Wiley for helping me
write this book. A big thanks goes to my technical editor Erik Westenius for his eye for details and making sure
that my code and examples are understandable. Also, a thank you to Kristoffer Åberg at Sony Mobile for giving
me valuable input on the UI design sections.
Contents
Introduction................................................................................................................................1
Who This Book Is For .............................................................1
What This Book Covers ...........................................................2
How This Book Is Structured ......................................................2
What You Need to Use This Book .................................................5
Source Code .....................................................................5
Errata ............................................................................5
Part I Building a Better Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 1 Fine-Tuning Your Development Environment .....................................9
Operating Systems for Android Development .....................................9
Advanced Android SDK Tools .....................................................9
The adb Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Stress-Testing an Application’s UI with Monkey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
The Gradle Build System for Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Optimize and Obfuscate with ProGuard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Android Library Projects and Third-Party Libraries ................................17
Precompiled JAR Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Setting Up a Library Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Version Control and Source Code Management ..................................19
Mastering Your IDE ..............................................................22
Debugging Android Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Static Code Analysis with lint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Refactoring Your Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Developer Options on Android Devices ..........................................29
Understanding Developer Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Summary .......................................................................32
Further Resources ...............................................................32
Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Websites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
viii Contents
Chapter 2 Efficient Java Code for Android ...............................................................33
Comparing Android’s Dalvik Java to Java SE ......................................33
Optimizing Java Code for Android ...............................................36
Type-Safe Enum on Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Enhanced For-Loop on Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Queues, Synchronization, and Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Memory Management and Allocations ...........................................40
Reducing Object Allocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Multithreading on Android ......................................................44
Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
AsyncTask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Picking the Right Solution for Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Summary .......................................................................52
Further Resources ...............................................................53
Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Online Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Part II Getting the Most Out of Components . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 3 Components, Manifests, and Resources..............................................57
Android Components ...........................................................57
The Activity Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
The Service Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
The BroadcastReceiver Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
The ContentProvider Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
The Application Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Application Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
The Android Application Manifest ...............................................62
The Manifest Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Google Play Filters and Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
The Application Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Component Elements and Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Intent Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Resources and Assets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Advanced String Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Localization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Using Resource Qualifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Using Assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74