Book Image

Android 3.0 Application Development Cookbook

By : Kyle Merrifield Mew
Book Image

Android 3.0 Application Development Cookbook

By: Kyle Merrifield Mew

Overview of this book

<p>Android is a mobile operating system that runs on a staggering number of smartphones and tablets. Android offers developers the ability to build extremely rich and innovative applications written using the Java programming language. Among the number of books that have been published on the topic, what&rsquo;s missing is a thoroughly practical, hands-on book that takes you straight to getting your job done without boring you with too much theory.<br /><br />Android 3.0 Application Development Cookbook will take you straight to the information you need to get your applications up and running. This book is written to provide you with the shortest possible route between an idea and a working application. <br /><br />Work through the book from start to finish to become an Android expert, or use it as a reference book by applying recipes directly to your project.<br /><br />This book covers every aspect of mobile app development, starting with major application components and screen layout and design, before moving on to how to manage sensors such as internal gyroscopes and near field communications. Towards the end, it delves into smartphone multimedia capabilities as well as graphics and animation, web access, and GPS. <br /><br />Whether you are writing your first app or your hundredth, this is a book that you will come back to time and time again, with its many tips and tricks on the rich features of Android 3.</p>
Table of Contents (18 chapters)
Android 3.0 Application Development Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Detecting multi-touch elements


Detecting touch on just a single point is useful enough, but far more information can be gathered from a touchscreen that can detect and distinguish the presence of more than one finger. Android can, in theory, detect up to 256 touch events at once, although one can see how this might be difficult to achieve in practice.

The programming of multi-touch events is necessarily more complex than tracing a single point but thankfully for us, it is achieved in a similar manner. Here we will see how to determine the number of touch events at a given moment and how to differentiate between them.

Getting ready

As mentioned earlier, detecting multiple touch events is similar to detecting single touch events. Start this task from where we left off in the previous recipe or apply the techniques laid out here to a project of your own.

How to do it...

  1. We will be adding to our previous OnTouchListener so open the Java activity and scroll down to the onTouch() method.

  2. Near the top...