Pro Android Pythonwith SL4A

Paul Ferrill

Apress·

Pro Android Python with SUA

Copyright © 2011 by Paul Ferrill

All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,electronic or mechanical, including photocopying, recording, or by any information storage or retrievalsystem, without the prior written permission of the copyright owner and the publisher.

ISBN-13 (pbk): 978-1-4302-3569-9

ISBN-13 (electronic): 978-1-4302-3570-5

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The use in this publication of trade names, trademarks, service marks, and similar terms, even if they arenot identified as such, is not to be taken as an expression of opinion as to whether or not they are subjectto proprietary rights.

President and Publisher: Paul ManningLead Editor: Tom WelshTechnical Reviewer: Justin GrarnmensEditorial Board: Steve Anglin, Mark Beckner, Ewan Buckingham, Gary Cornell, Jonathan Gennick,

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To my wife, Sandy, for your tireless support ofme and ourfamily. I could not have done this without you.And to my wondeiful children who put up with a preoccupied daddy for way too long.

-Paul Ferrill

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Contents at aGlance

About the Author ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• xi

About the Technical Reviewer xii

Acknowledgments ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• xiii

Preface •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• xiv

-Chapter 1: Introduction •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••1

.f Chapter 2: Getting Started 27

'~Chapter 3: Navigating the Android SDK 57

i Chapter 4: Developing with Eclipse 83

Chapter 5: Exploring the Android APi •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 113

_Chapter 6: Background Scripting with Python 139

--;:,~ Chapter 7: Python Scripting Utilities ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 165

-<~ Chapter 8: Python Dialog Box-based GUls 195

Chapter 9: Python GUls with HTML•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 221

-'8 Chapter 10: Packaging and Distributing 249

Index•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••273

Contents

About the Author ..............................•....................••............................•.•.•.••......••••••.•xi

About the Technical Reviewer xii

Acknowledgments ............................•......................................................................xiii

Preface .....................................•..............................................................................xiv

Chapter 1: Introduction 1

Why SL4A? 1

The World of Android 2

Android Application Anatomy 2

Activities 3

Intents 3

SL4A History 4

SL4A Architecture 4

SL4A Concepts 6

JavaScript Object Notation (JSON) 6

Events 7

Languages 7

Beanshell 2.0b4 7

Lua 5.1.4 8

Perl 5.1 0.1 9

PHP 5.3.3 11

Rhino 1.7R2 11

v

"CONTENTS

JRuby 1.4 12

Shell 13

Python 13

Summary 26

",:Chapter 2: Getting Started 27

Installing SL4A on the Device 27

Installing the Android SDK 39

Linux 39

Mac as x 41

Windows 41

Installing Python 43

Remotely Connecting to the Device 45

Device Settings 49

Executing Simple Programs 51

Summary 55

;·}'Chapter 3: NaVigating the Android SDK 57

Wading Through the SDK Documentation 57

Examining the Different SDK Components 59

Testing With the Android Emulator 60

Android Debug Bridge...............................•.............................................................................................68

Dalvik Debug Monitor Service (DDMS) 79

Summary 81

~Chapter 4: Developing with Eclipse 83

Installing Eclipse on a Development Machine 83

Eclipse Basics 88

Perspectives 90

Projects 93

vi

sCONTENTS

Android Development Toolkit. 94

Using Pydev 99

Using MUltiple File Types in Eclipse 107

Summary 110

f Chapter 5: Exploring the Android APi 113

Exploring the Android APls 115

Android Facades 116

ActivityResultFacade 118

AndroidFacade 118

ApplicationManagerFacade 121

BatteryManagerFacade 121

BluetoothFacade 123

CameraFacade 123

CommonlntentsFacade 124

ContactsFacade 125

EventFacade '" 127

EyesFreeFacade 127

LocationFacade 127

MediaPlayerFacade 128

MediaRecorderFacade 128

PhoneFacade 128

PreferencesFacade 128

SensorManagerFacade 129

SettingsFacade 130

SignalStrengthFacade 130

SmsFacade 131

SpeechRecognitionFacade 132

TextToSpeechFacade 132

ToneGeneratorFacade 132

vii

~CONTENTS

UiFacade 132

WakeLockFacade 137

WebCamFacade 137

WifiFacade 137

Summary 138

-Chapter 6: Background Scripting with Python 139

Background Tasks 139

Triggers 141

Orientation-based Actions 142

Location-based Actions 145

Time-based Actions 146

Elapsed Time-based Triggers 148

FTP File Sync Tool. 150

Syncing Photos with Flickr 158

Syncing with Google Docs 160

AStartup Launcher 162

Summary 164

vqChapter 7: Python Scripting Utilities 165

Python Libraries 165

E-mail-Based Applications 168

Location-Aware Applications 172

Tweet My Location 172

Killing a Running App 186

URL File Retriever 188

Python FTP Server 190

Summary 194

viii

",-CONTENTS

Chapter 8: Python Dialog Box-based GUls 195

UI Basics 195

Book Title Search 199

Convenience Dialog Boxes 201

Progress Dialog Boxes 203

Modal versus Non-Modal Dialog Boxes 205

Options Menu 207

File Listing with dialogCreateAlert 207

Dialog Boxes as Python Objects 209

Podplayer App 213

Building the mysettings App 216

Summary 220

-'ill Chapter 9: Python GUls with HTML 221

HTML and Basic Information Display 221

HTML and JavaScript. 224

HTML GUI Form Basics 226

Simple HTML Forms 228

Cascading Style Sheets 230

SMS Merger 233

Summary 247

ill Chapter 10: Packaging and Distributing 249

QR Codes 249

Application Packages 251

Packaging Your Own Application 264

Building with Ant 264

Compiling SL4A 266

Finishing Touches 269

ix

x

[CONTENTS

Winding Down 271

Summary 271

Index................................................•.........•............................................................273

About the Author

:Paul Ferrill has a BS and MS in electrical engineering and has beenwriting about computers for more than 25 years. He currently serves asCTO for Avionics Test and Analysis Corporation, working on multiple DoDprojects. Software development has been his primary focus, along witharchitecting large-scale data management and storage systems. He alsoserves on several DoD standards committees, providing input to the nextgeneration of data recording and transmission standards.

He has a long history with both Microsoft and open sourcetechnologies. His two favorite languages are Visual Basic and Python. He'shad articles published in PC Magazine, PC Computing, InfoWorld,Computer World, Network World, Network Computing, Federal ComputerWeek, Information Week, and multiple web sites.

xi

xii

About the Technical Reviewer

Justin Grammens has been writing software for 12 years, holds a mastersdegree in Software Systems, and has a patent pending on the process of asystem to collect and rate digital media. He has written applications for avariety of mobile platforms in a number of different market sectors and is thecofounder of Recursive Awesome, LLC; owner of Localtone, LLC; and founderof Mobile Twin Cities.

Justin has built online e-commerce systems, real-time mappingsolutions, large-scale tax accounting software, and technology for Internetradio stations. Having worked with Android since version l.0, Justin hasspoken on mobile technology at conferences and software developmentgroups since 2008.

Justin has developed Android applications for Best Buy, McDonald's,BuzzFeed, and Consolidated Knowledge; and is co-creator of a cross-platform

streaming video service called Mobile Vidhub. Justin is employed by Code 42 as a Director of MobileTechnology and lives in S1. Paul, MN, with his wife.

Acknowledgments

I would like to acknowledge the excellent staff at Apress who managed to get this book completed ontime through multiple delays and reworking of the original title. You've made the process much lessfrightening for a first-time author than I expected.

A special thanks goes to coordinating editors Mary Tobin and Corbin Collins, and to Tom Welsh, thelead editor.

I'd also like to thank Frank Pohlmann for convincing me to do this project in the first place.Thank you to the technical reviewer, Justin Grammens, for a keen set of eyes and helpful comments.

A big thank you to Robbie Matthews, who has become one of the primary contributors to the SUAproject and provided help when things didn't make sense.

Thanks also to the folks at TechSmith, and Betsy Weber in particular, for their fantastic Snagitproduct, without which the screenshots would have been so much harder.

Final thanks go to my son Micah Ferrill for his help with the Python code.

xiii

xiv

Preface

It's no secret that traditional computing patterns are undergoing a radical change. The proliferation ofsmartphones with ever-increasing processing power will only accelerate the process. Tablet devices haveseen a much broader adoption as extensions of the smartphone platform where previous attempts todownsize general-purpose computers failed. While the operating system of the most popular mobiledevices may be different from the user's perspective, it has more in common with a desktop system thanyou might think.

Google's Android platform has seen a huge increase over the last year and is challenging Apple's iOSfor market share. Apple's wide lead in applications has been steadily dwindling although the jury is stillout when it comes to quality. Building those applications has, for the most part, been restricted toObjective C for iOS and Java for Android. There are a few other options ifyou take into consideration theMonoTouch and MonoDroid projects, but that's about it.

Mobile devices will probably never completely replace traditional computers, although the divisionof activity will continue to swing toward the one you have access to the most. This book is aboutbringing some of the flexibility you get with a desktop computer in the form of writing simple programsor scripts to accomplish a specific task. I know I've learned a lot along the way, and it is my sincere hopethat through reading this book you will glean a thing or two as well.