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

Controlling layout during runtime


Specifying the UI with XML and keeping the layout separate from the application code makes for easily maintainable projects and allows us to specify different layouts based on locale, orientation, pixel density, docking status, and other configuration parameters.

Despite the tidiness of this approach there are occasions when we need to manipulate a layout or another view group at runtime from within a Java method. All XML code is interpreted by Java and we have access to ViewGroup parameters through various LayoutParams classes.

Getting ready

Here we will set up a simple layout with XML and use a LinearLayout.LayoutParams object to change the margins of a View during run time.

Start a new Android project and navigate to the main.xml file in the res/layout folder.

How to do it....

  1. Open the Graphical Layout tab and edit the default TextView so that it looks like the one here:

    <TextView
      android:text="This layout was defined in XML"
      android:id="@+id/text_view...