Book Image

Android 9 Development Cookbook - Third Edition

By : Rick Boyer
Book Image

Android 9 Development Cookbook - Third Edition

By: Rick Boyer

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! With this extensively updated cookbook, you'll find solutions for working with the user interfaces, multitouch gestures, location awareness, web services, and device features such as the phone, camera, and accelerometer. You also get useful steps on packaging your app for the Android Market. Each recipe provides a clear solution and sample code you can use in your project from the outset. 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 Pie.
Table of Contents (24 chapters)
Title Page
Copyright and Credits
Dedication
About Packt
Contributors
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 can we do this with OpenGL?

This recipe will demonstrate how to rotate the triangle, as the following 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 the projection and camera view while drawing. Refer to the previous recipe if you have not already completed those steps.

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...