Master Android from first principles and begin the journey toward your own successful Android applications!
Dear Reader,
First, welcome to the world of Android! We’re entering a new era of mobile application development, one marked by open platforms and open source, to take ‘walled gardens’ and make them green houses for any and all to participate in. Android is relatively easy for developers, and I believe that this innovation will help generate a large ecosystem of developers and consumers within a very short time. This means that budding developers such as yourself will have many opportunities to design and build your own applications and you’ll have a huge and hungry customer base.
Second, welcome to the book! Its purpose is to start you on your way with building Android applications, and to help you master the learning curve. Android is already a rich framework, comparable in many ways to the richness Android of desktop Java environments. This means that there is a lot of cool stuff for you to pick up along your journey in order to create the slickest, most useful apps Android you can imagine.
The source code for the code samples in this book is all available from the Apress site, so you can stay as hands-on and practical as you like while I introduce you to the core of Android, and invite you to experiment with the various classes and APIs we’ll be looking at. By the time you’ve finished this book, you’ll be creating your own Android applications and asking yourself what your next great application will be…!
Enjoy!
Mark Murphy
Audio Playback Options
Audio Playback Options
The SoundPool class, largely undocumented in Android 1.1, is now ready for widespread use in Android 1.5. The SoundPool is designed to play back multiple overlapping sounds, particularly useful for games. Moreover, you can specify priorities for these audio streams and a maximum number of streams, so your application can simply play back clips as needed (e.g., based on game events), and Android will ensure the maximum number of streams is not exceeded. That way, you can minimize the amount of CPU power audio playback requires.
Android 1.5 also offers AudioTrack, whereby the device can play back audio that your code converts, perhaps from a streaming source, into PCM data. So, for example, should you want to implement a Voice-Over-IP (VOIP) application, you might use AudioTrack to handle playback of the audio coming off of, say, the SIP connection.
Android 1.5 also introduces the JetPlayer, designed to play back JET interactive music filesJET interactive music files.
