Book Image

Android Application Development Cookbook - Second Edition

By : Kyle Mew
Book Image

Android Application Development Cookbook - Second Edition

By: Kyle Mew

Overview of this book

The Android OS has the largest installation base of any operating system in the world; there has never been a better time to learn Android development to write your own applications, or to make your own contributions to the open source community! This “cookbook” will make it easy for you to jump to a topic of interest and get what you need to implement the feature in your own application. If you are new to Android and learn best by “doing,” then this book will provide many topics of interest. Starting with the basics of Android development, we move on to more advanced concepts, and we’ll guide you through common tasks developers struggle to solve. The first few chapters cover the basics including Activities, Layouts, Widgets, and the Menu. From there, we cover fragments and data storage (including SQLite), device sensors, the camera, and GPS. Then we move on more advanced topics such as graphics and animation (including OpenGL), multi-threading with AsyncTask, and Internet functionality with Volley. We’ll also demonstrate Google Maps and Google Cloud Messaging (also known as Push Notifications) using the Google API Library. Finally, we’ll take a look at several online services designed especially for Android development. Take your application big-time with full Internet web services without having to become a server admin by leveraging the power of Backend as a Service (BaaS) providers.
Table of Contents (23 chapters)
Android Application Development Cookbook Second Edition
Credits
Disclaimer
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Moving the triangle with rotation


What we've demonstrated so far with OpenGL would probably be easier using the traditional canvas or drawable objects. This recipe will show a bit of the power of OpenGL by rotating the triangle. Not that we can't create movement with the other drawing methods, but how easily we can do this with OpenGL!

This recipe will demonstrate how to rotate the triangle, as this screenshot shows:

Getting ready

Create a new project in Android Studio and call it: CreatingMovement. Use the default Phone & Tablet options and select Empty Activity when prompted for Activity Type.

This recipe builds on the previous recipe Applying Projection and Camera View While Drawing. If you have not already typed in the previous recipe, do so before continuing.

How to do it...

Since we are continuing from the previous recipe, we have very little work to do. Open MainActivity.java and follow these steps:

  1. Add a Matrix to the GLRendered class:

    private float[] mRotationMatrix = new float[16]...