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

Storing public data on external storage


Nearly all Android devices come equipped with some form of external memory, very often in the form of an SD card. We can use such devices to store shared files that are available to the user from within our application.

The most straightforward way to write to an SD card is the Java FileWriter object but because of the removable nature of external storage, we need some way to check the status of our memory before we attempt to access it. Android provides the android.os.Environment class for us to accomplish this.

Getting ready

Most of this exercise is done using Java code but we will need a layout with a single TextView to observe our results, so start up a new Android project in Eclipse and edit the main.xml file so that it contains one TextView.

How to do it...

  1. Provide the TextView we just created with an ID and associate it with a private field in Java with the findViewById() method.

  2. Also create a private FileWriter called mFileWriter.

  3. Inside the onCreate...