Contents at a Glance Contents v About the Author . x About the Technical Reviewer . xi Acknowledgments xii Introduction . xiii ■Chapter 1: Preliminary Information: Before We Get Started . 1 ■Chapter 2: What’s Next? Our Road Ahead . 11 ■Chapter 3: Setting Up Your Android Development Environment . 19 ■Chapter 4: Introducing the Android Software Development Platform . 41 ■Chapter 5: Android Framework Overview . 67 ■Chapter 6: Screen Layout Design: Views and Layouts 89 ■Chapter 7: UI Design: Buttons, Menus, and Dialogs 115 ■Chapter 8: An Introduction to Graphics Resources in Android . 147 ■Chapter 9: Adding Interactivity: Handling UI Events . 183 ■Chapter 10: Understanding Content Providers 217 ■Chapter 11: Understanding Intents and Intent Filters . 255 ■Chapter 12: The Future 297 Index . 311xiii Introduction Over the last two years, Google’s Android operating system (OS) has gone from a virtually unknown open source solution to the current mobile OS market leader among all mobile handsets, with over one-third of the market share, and it’s still climbing rapidly. Android has even started to dominate the tablet OS marketplace, and is also the foundation for the popular iTV OS known as GoogleTV. There seems to be no end in sight for Android’s rocketing success, which is great news for owners of this book. I’ve heard a great many people say, “I have a really phenomenal idea for a smartphone application! Can you program it for me!?” Rather than sit back and code all of these applications for everyone, I thought it might be a smarter idea to write a book about how an absolute beginner could code an Android application using open source tools that cost nothing to download and that are free for commercial use, and then leverage that new found knowledge to reach their dream of making their application idea a revenue-generating reality. Thanks to open source and Google’s Android development environment, Oracle’s Java programming Language, Linus Torvald’s Linux operating system, the Eclipse code editing software, and this book, vaporizing a software product out of thin air, and at no production cost other than your PC and “sweat equity,” is now a complete reality. The Target: The Programming Neophyte As you may have inferred from the title, this book assumes that you have never programmed before in any programming language. It is written for someone who has never written a single line of code before, and who is thus unfamiliar with object-oriented programming (OOP) languages such as Oracle’s Java and mark-up languages such as XML. Both of these open source languages are used extensively in creating Android applications. There are lots of Java and Android books out there, but all of these books assume you have programmed before, and know all about OOP. I wanted to write a book that takes readers from knowing absolutely nothing about programming or knowing how to install a Software Development Kit (SDK) and Integrated Development Environment (IDE) all the way to being able to program Android applications using Java and XML. The Weapon: Android, the Innovative Mobile Code Environment Android is my Internet 2.0 development weapon of choice, because it allows me to develop highly advanced applications for the primary Internet 2.0 devices, including the main three where revenue potential is by far the greatest: ■ INTRODUCTION xiv ã Smartphones ã Tablets ã iTV or Interactive Television The other reason I place my bets on Android is because it is open source, and thus free from royalties and politics. I do not have to submit my Android application to any company and ask permission to publish it, as long as it is not harmful in any way to others. For this reason, and due to the free for commercial use nature of open source software, there is little external risk involved in developing an application for the Android Platform. How This Book Is Organized Because this is a book for absolute beginners, we start at the very beginning, showing where to download and how to install the various Android, Java, and Eclipse environments, as well as how to configure these environments and how to set them up for application development and testing. This in itself is no easy task, and must be done correctly, as these tools provide the foundation for all of our Android development, debugging, and testing for the remainder of the book. Next I will provide you with an overview of where Android came from, why, how, and when Google acquired it, and how it is uniquely structured among software development platforms. I will introduce XML, Java, OOP, and Android concepts soon after that, as well as cover how Android manages its screen layout. We will then move these concepts into use in later chapters in the second half of the book; these chapters explain the most important concepts in Android in their most logical order as they pertain to applications development. In that second half of the book, we’ll start getting into developing a user interface (UI), as that is the front-end or interface for your user to your Android application. Soon after we'll cover how your UI talks to your application via events processing. To spice up your application’s visual appearance, we’ll get into graphics, animation, and video, and then get into even more advanced topics after that, such as databases and communications. Finally we will look at some of the advanced features of Android that you will want to visit after finishing the book; these are topics that are too advanced for a first book on Android but which provide some of the coolest features in smartphone development today. We’ll walk you through all of these topics and concepts with screenshots of the IDE and visual examples and then take you though step-by-step examples reinforcing these concepts. Sometimes we will repeat previous topics to reinforce what you have learned and apply these skills in new ways. This enables new programmers to re-apply development skills and feel a sense of accomplishment as they progress. The Formula for Success Learning to develop an Android application is an interactive process between you and the tools and technologies (Eclipse, XML, Java, Android, and so on) that I cover in this book. Just like learning to play a sport, you have to develop skills and practice them daily. You need to work through the examples and exercises in this book, more than once if necessary to become comfortable with each concept. Just because you understand a concept that doesn’t necessarily mean you will know how to apply it creatively and use it effectively; that takes practice, and ultimately will happen when the “ah-ha” moment occurs, when you understand the concept in context with the other concepts that interconnect with it. You will learn quite a bit about how Android works from this introductory book. You will glean a lot of insight into the inner working of Android by working through all of the exercises in this book. But you will also learn new things not specifically mentioned in this book when you compile, run and debug your programs. Spending time experimenting with your code and trying ■ INTRODUCTION xv to find out why it is not working the way you want, or trying to add new features to it, is a learning process that is very valuable. The downside of debugging is it can sometimes be quite frustrating to the new developer. If you have never wanted to put a bullet in your computer monitor, you will soon. You will question why you are doing this, and whether you are savvy enough to solve the problem. Programming can be very humbling, even for the most experienced of developers. Like an athlete, the more you practice, the better you will become at your skill. You can do some truly amazing things as an Android programmer. The world is your oyster. It is one of the most satisfying accomplishments you can have, seeing your app in the Android App Store. However, there is a price, and that price is time spent practicing your coding. Here is our formula for success: ã Trust that you can pull it off. You may be the only one who says you can’t do this. Don’t tell yourself that. ã Work through all the examples and exercises in this book, twice if necessary, until you understand them. ã Code, code some more, and keep coding – don't stop. The more you code, the better you’ll get. ã Be patient with yourself. If you were fortunate enough to have been a star pupil who can memorize material simply by reading it, this will not happen with Java and XML coding. You are going to have to spend lots of time coding in order to understand what is happening inside the OS. ã Whatever you do: DON’T GIVE UP! Required Software, Materials, and Equipment One of the great things about Java, Android and Eclipse is they are available in both 32-bit and 64- bit versions on the three primary operating systems in use today: ã Windows ã Mac ã Linux The other great thing about Java, Android and Eclipse is that they are free. You can download Android at http://developer.android.com/SDK/. For equipment, any modern computer will do. Fortunately they are only $250 to $500 brand new on www.PriceWatch.com and an OS such as SUSE Linux is free and an amazing development operating system. SUSE Linux V11 can be downloaded at www.OpenSUSE.com and is currently at version 11.4 and very stable. Operating System and IDE Although you can use Android on many platforms, the Eclipse integrated development environment (IDE) that developers use to develop Android apps is most commonly used on an Intel-based Windows or Linux PC. The Eclipse IDE is free and is available on the Internet at www.eclipse.org. The operating system should be Windows XP or later or SUSE Linux 11.4 or later to run Eclipse most effectively. ■ INTRODUCTION xvi Software Development Kits You will need to download the Eclipse IDE from Eclipse and the Android SDK from Google. This is available at http://developer.android.com/SDK/. Dual Monitors It is highly recommended that developers have a second monitor connected to their computer. It is great to step through your code and watch your output window and Android emulator at the same time on dual, independent monitors. Today’s PC hardware makes this easy. Just plug your second monitor in to the second display port of any Intel-based PC or laptop, with the correct display port adapter, of course, and you’re able to have two monitors working independently from one another. Note it is not required to have dual mo
