Apress Pro Android Apps Performance Optimization

278 Pages·2012·2.63 MB·English

Pro Android Apps
Performance
Optimization

■ ■ ■
Hervé Guihot

i
Pro Android Apps Performance Optimization
Copyright © 2012 by Hervé Guihot
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ISBN-13 (pbk): 978-1-4302-3999-4
ISBN-13 (electronic): 978-1-4302-4000-6
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President and Publisher: Paul Manning
Lead Editor: James Markham
Technical Reviewer: Charles Cruz, Shane Kirk, Eric Neff
Editorial Board: Steve Anglin, Mark Beckner, Ewan Buckingham, Gary Cornell, Morgan Ertel,
Jonathan Gennick, Jonathan Hassell, Robert Hutchinson, Michelle Lowman,
James Markham, Matthew Moodie, Jeff Olson, Jeffrey Pepper, Douglas Pundick,
Ben Renow-Clarke, Dominic Shakeshaft, Gwenan Spearing, Matt Wade, Tom Welsh
Coordinating Editor: Corbin Collins
Copy Editor: Jill Steinberg
Compositor: MacPS, LLC
Indexer: SPi Global
Artist: SPi Global
Cover Designer: Anna Ishchenko
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Contents at a Glance
Contents ............................................................................................................. iv
About the Author .............................................................................................. viii
About the Technical Reviewers ......................................................................... ix
Acknowledgments .............................................................................................. x
Introduction ....................................................................................................... xi
■Chapter 1: Optimizing Java Code .................................................................... 1(cid:2)
■Chapter 2: Getting Started With the NDK ....................................................... 33(cid:2)
■Chapter 3: Advanced NDK .............................................................................. 73(cid:2)
■Chapter 4: Using Memory Efficiently ........................................................... 109(cid:2)
■Chapter 5: Multithreading and Synchronization ......................................... 133(cid:2)
■Chapter 6: Benchmarking And Profiling ...................................................... 163(cid:2)
■Chapter 7: Maximizing Battery Life ............................................................. 177(cid:2)
■Chapter 8: Graphics ..................................................................................... 207(cid:2)
■Chapter 9: RenderScript .............................................................................. 231(cid:2)
Index ............................................................................................................... 265
iii
Contents
Contents at a Glance .......................................................................................... iii(cid:2)
About the Author. ............................................................................................. viii(cid:2)
About the Technical Reviewers ......................................................................... ix(cid:2)
Acknowledgments .............................................................................................. x(cid:2)
Introduction ....................................................................................................... xi(cid:2)

■Chapter 1: Optimizing Java Code .................................................................... 1(cid:2)
(cid:2)
How Android Executes Your Code ........................................................................................................................... 2
(cid:2)
Optimizing Fibonacci .............................................................................................................................................. 4
(cid:2)
From Recursive To Iterative ............................................................................................................................... 5
(cid:2)
BigInteger .......................................................................................................................................................... 6
(cid:2)
Caching Results .................................................................................................................................................... 11
(cid:2)
android.util.LruCache<K, V> ............................................................................................................................ 12
(cid:2)
API Levels ............................................................................................................................................................. 13
(cid:2)
Fragmentation .................................................................................................................................................. 16
(cid:2)
Data Structures ..................................................................................................................................................... 17
(cid:2)
Responsiveness .................................................................................................................................................... 20
(cid:2)
Lazy initializations ........................................................................................................................................... 22
(cid:2)
StrictMode ....................................................................................................................................................... 23
(cid:2)
SQLite ................................................................................................................................................................... 25
(cid:2)
SQLite Statements ........................................................................................................................................... 25
(cid:2)
Transactions .................................................................................................................................................... 28
(cid:2)
Queries ............................................................................................................................................................. 30
(cid:2)
Summary .............................................................................................................................................................. 31
■Chapter 2: Getting Started With the NDK ....................................................... 33(cid:2)
(cid:2)
What Is In the NDK? .............................................................................................................................................. 34
(cid:2)
Mixing Java and C/C++ Code ............................................................................................................................... 37
(cid:2)
Declaring the Native Method ........................................................................................................................... 37
(cid:2)
Implementing the JNI Glue Layer ..................................................................................................................... 38
(cid:2)
Creating the Makefiles ..................................................................................................................................... 40
(cid:2)
Implementing the Native Function ................................................................................................................... 41
(cid:2)
Compiling the Native Library ............................................................................................................................ 43
(cid:2)
Loading the Native Library ............................................................................................................................... 43
iv
■ CONTENTS

(cid:2)
Application.mk ...................................................................................................................................................... 44
(cid:2)
Optimizing For (Almost) All Devices ................................................................................................................. 46
(cid:2)
Supporting All Devices ..................................................................................................................................... 47
(cid:2)
Android.mk ........................................................................................................................................................... 50
(cid:2)
Performance Improvements With C/C++ .............................................................................................................. 53
(cid:2)
More About JNI ................................................................................................................................................ 57
(cid:2)
Native Activity ....................................................................................................................................................... 62
(cid:2)
Building the Missing Library ............................................................................................................................ 64
(cid:2)
Alternative ........................................................................................................................................................ 70
(cid:2)
Summary .............................................................................................................................................................. 71
■Chapter 3: Advanced NDK .............................................................................. 73(cid:2)
(cid:2)
Assembly .............................................................................................................................................................. 73
(cid:2)
Greatest Common Divisor ................................................................................................................................ 74
(cid:2)
Color Conversion .............................................................................................................................................. 79
(cid:2)
Parallel Computation of Average ..................................................................................................................... 82
(cid:2)
ARM Instructions .............................................................................................................................................. 87
(cid:2)
ARM NEON ....................................................................................................................................................... 96
(cid:2)
CPU Features ................................................................................................................................................... 97
(cid:2)
C Extensions ......................................................................................................................................................... 98
(cid:2)
Built-in Functions ............................................................................................................................................. 99
(cid:2)
Vector Instructions ........................................................................................................................................... 99
(cid:2)
Tips ..................................................................................................................................................................... 103
(cid:2)
Inlining Functions ........................................................................................................................................... 104
(cid:2)
Unrolling Loops .............................................................................................................................................. 104
(cid:2)
Preloading Memory ........................................................................................................................................ 105
(cid:2)
LDM/STM Instead Of LDR/STD ....................................................................................................................... 106
(cid:2)
Summary ............................................................................................................................................................ 107
■Chapter 4: Using Memory Efficiently ........................................................... 109(cid:2)
(cid:2)
A Word On Memory ............................................................................................................................................. 109
(cid:2)
Data Types .......................................................................................................................................................... 111
(cid:2)
Comparing Values .......................................................................................................................................... 113
(cid:2)
Other Algorithms ............................................................................................................................................ 115
(cid:2)
Sorting Arrays ................................................................................................................................................ 116
(cid:2)
Defining Your Own Classes ............................................................................................................................ 117
(cid:2)
Accessing Memory .............................................................................................................................................. 118
(cid:2)
The Cache’s Line Size .................................................................................................................................... 119
(cid:2)
Laying Out Your Data .......................................................................................................................................... 120
(cid:2)
Garbage Collection .............................................................................................................................................. 125
(cid:2)
Memory Leaks ............................................................................................................................................... 125
(cid:2)
References ..................................................................................................................................................... 127
(cid:2)
APIs ..................................................................................................................................................................... 131
(cid:2)
Low Memory ....................................................................................................................................................... 131
(cid:2)
Summary ............................................................................................................................................................ 132
■Chapter 5: Multithreading and Synchronization ......................................... 133(cid:2)
(cid:2)
Threads ............................................................................................................................................................... 134
(cid:2)
AsyncTask ........................................................................................................................................................... 137
(cid:2)
Handlers and Loopers ......................................................................................................................................... 140
v
■ CONTENTS

(cid:2)
Handlers ......................................................................................................................................................... 140
(cid:2)
Loopers .......................................................................................................................................................... 142
(cid:2)
Data Types .......................................................................................................................................................... 143
(cid:2)
Synchronized, Volatile, Memory Model .......................................................................................................... 143
(cid:2)
Concurrency ........................................................................................................................................................ 147
(cid:2)
Multicore ............................................................................................................................................................. 148
(cid:2)
Modifying Algorithm For Multicore ................................................................................................................ 149
(cid:2)
Using Concurrent Cache ................................................................................................................................ 152
(cid:2)
Activity Lifecycle ................................................................................................................................................. 154
(cid:2)
Passing Information ....................................................................................................................................... 156
(cid:2)
Remembering State ....................................................................................................................................... 158
(cid:2)
Summary ............................................................................................................................................................ 161
■Chapter 6: Benchmarking And Profiling ...................................................... 163(cid:2)
(cid:2)
Measuring Time .................................................................................................................................................. 163
(cid:2)
System.nanoTime() ........................................................................................................................................ 164
(cid:2)
Debug.threadCpuTimeNanos() ....................................................................................................................... 165
(cid:2)
Tracing ................................................................................................................................................................ 167
(cid:2)
Debug.startMethodTracing() .......................................................................................................................... 167
(cid:2)
Using the Traceview Tool ............................................................................................................................... 168
(cid:2)
Traceview in DDMS ........................................................................................................................................ 170
(cid:2)
Native Tracing ................................................................................................................................................ 172
(cid:2)
Logging ............................................................................................................................................................... 174
(cid:2)
Summary ............................................................................................................................................................ 176
■Chapter 7: Maximizing Battery Life ............................................................. 177(cid:2)
(cid:2)
Batteries ............................................................................................................................................................. 177
(cid:2)
Measuring Battery Usage ............................................................................................................................... 180
(cid:2)
Disabling Broadcast Receivers ........................................................................................................................... 183
(cid:2)
Disabling and Enabling the Broadcast Receiver ............................................................................................ 186
(cid:2)
Networking ......................................................................................................................................................... 187
(cid:2)
Background Data ........................................................................................................................................... 188
(cid:2)
Data Transfer ................................................................................................................................................. 189
(cid:2)
Location .............................................................................................................................................................. 191
(cid:2)
Unregistering a Listener ................................................................................................................................ 193
(cid:2)
Frequency of Updates .................................................................................................................................... 193
(cid:2)
Multiple Providers .......................................................................................................................................... 194
(cid:2)
Filtering Providers .......................................................................................................................................... 196
(cid:2)
Last Known Location ...................................................................................................................................... 198
(cid:2)
Sensors ............................................................................................................................................................... 199
(cid:2)
Graphics .............................................................................................................................................................. 200
(cid:2)
Alarms ................................................................................................................................................................. 201
(cid:2)
Scheduling Alarms ......................................................................................................................................... 203
(cid:2)
WakeLocks .......................................................................................................................................................... 204
(cid:2)
Preventing Issues ........................................................................................................................................... 205
(cid:2)
Summary ............................................................................................................................................................ 206
■Chapter 8: Graphics ..................................................................................... 207(cid:2)
(cid:2)
Optimizing Layouts ............................................................................................................................................. 207
(cid:2)
RelativeLayout ............................................................................................................................................... 209
vi
■ CONTENTS

(cid:2)
Merging Layouts ............................................................................................................................................ 213
(cid:2)
Reusing Layouts ............................................................................................................................................. 214
(cid:2)
View Stubs ..................................................................................................................................................... 215
(cid:2)
Layout Tools ........................................................................................................................................................ 217
(cid:2)
Hierarchy Viewer ............................................................................................................................................ 218
(cid:2)
layoutopt ........................................................................................................................................................ 218
(cid:2)
OpenGL ES .......................................................................................................................................................... 218
(cid:2)
Extensions ...................................................................................................................................................... 219
(cid:2)
Texture Compression ..................................................................................................................................... 221
(cid:2)
Mipmaps ........................................................................................................................................................ 226
(cid:2)
Multiple APKs ................................................................................................................................................. 228
(cid:2)
Shaders .......................................................................................................................................................... 228
(cid:2)
Scene Complexity .......................................................................................................................................... 229
(cid:2)
Culling ............................................................................................................................................................ 229
(cid:2)
Render Mode .................................................................................................................................................. 229
(cid:2)
Power Consumption ....................................................................................................................................... 229
(cid:2)
Summary ............................................................................................................................................................ 230
■Chapter 9: RenderScript .............................................................................. 231(cid:2)
(cid:2)
Overview ............................................................................................................................................................. 231
(cid:2)
Hello World .......................................................................................................................................................... 233
(cid:2)
Hello Rendering .................................................................................................................................................. 236
(cid:2)
Creating a Rendering Script ........................................................................................................................... 237
(cid:2)
Creating a RenderScriptGL Context ............................................................................................................... 238
(cid:2)
Extending RSSurfaceView .............................................................................................................................. 239
(cid:2)
Setting the Content View ............................................................................................................................... 239
(cid:2)
Adding Variables to Script .................................................................................................................................. 240
(cid:2)
HelloCompute ...................................................................................................................................................... 243
(cid:2)
Allocations ..................................................................................................................................................... 244
(cid:2)
rsForEach ....................................................................................................................................................... 245
(cid:2)
Performance .................................................................................................................................................. 248
(cid:2)
Native RenderScript APIs .................................................................................................................................... 249
(cid:2)
rs_types.rsh ................................................................................................................................................... 250
(cid:2)
rs_core.rsh ..................................................................................................................................................... 253
(cid:2)
rs_cl.rsh ......................................................................................................................................................... 255
(cid:2)
rs_math.rsh ................................................................................................................................................... 259
(cid:2)
rs_graphics.rsh .............................................................................................................................................. 260
(cid:2)
rs_time.rsh .................................................................................................................................................... 261
(cid:2)
rs_atomic.rsh ................................................................................................................................................. 262
RenderScript vs. NDK .......................................................................................................................................... 263
(cid:2)
Summary ............................................................................................................................................................ 263
Index ............................................................................................................... 265

vii
About the Author
Hervé Guihot started learning about computers more than 20 years ago with
an Amstrad CPC464. Although the CPC464 is most likely the reason why he still
appreciates green-screened devices (ask him about his phone), Hervé started
working with Android as it became a popular platform for application
development. It was also was the only platform that combined two of his main
passions: software and pastries. After many years working in the world of
interactive and digital television, he is focused on bringing Android to more
devices to encourage more developers to leverage the power of Android and
more people to have access to the technology. Hervé is currently a software
engineering manager in MediaTek (www.mediatek.com), a leading fabless
semiconductor company for wireless communications and digital multimedia solutions. He
holds an engineering degree from the Institut de Formation Supérieure en Informatique et
Télécommunication in Rennes, Brittany, and you can sometimes find him waiting in line for an
éclair on 18th and Guerrero.
viii
About the Technical Reviewers
Charles Cruz is a mobile application developer for the Android, iOS, and
Windows Phone platforms. He graduated from Stanford University with B.S.
and M.S. degrees in Engineering. He lives in Southern California and, when
not doing technical things, plays lead guitar in an original metal band
(www.taintedsociety.com) and a classic rock tribute band. Charles can be
reached at [email protected] and @CodingNPicking on
Twitter.

Shane Kirk earned his B.S. in Computer Science from the University of
Kentucky in 2000. He’s currently a software engineer for DeLorme, a mapping
and GPS technology company based in Yarmouth, Maine, where he spends his
days writing C++ and Java code for mobile and desktop applications. When
Shane isn’t coding, you’ll usually find him making lots of noise with his guitar
or lost in the pages of a good book.

Eric Neff is an experienced technical architect with more than 14 years of
overall experience in as a technical architect and senior software developer. He
is an expert in full life-cycle application development, middle-ware, and n-tier
application development, with specific expertise in Microsoft .NET application
development. He specializes in object-oriented analysis and design in systems
development with a focus on the scheduling of service personal or
manufactured items and was instrumental in the design and implementation
of data relation schemas for the lexicography industry. Eric was recently
promoted to Director of Mobile Innovations at Kiefer Consulting, Inc, putting
into practice several years of hobbyist development in the mobile space on
iPhone, Android, and Windows Mobile. Eric is active in the local development community
through his participation in the Sacramento Google Technology Group and as a board member of
the Sacramento Dot Net User Group. He has given presentations on mobile web technologies,
mobile development, and ASP.NET techniques.

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