Book Image

Learning Java by Building Android Games - Second Edition

By : John Horton
Book Image

Learning Java by Building Android Games - Second Edition

By: John Horton

Overview of this book

Android is one of the most popular mobile operating systems presently. It uses the most popular programming language, Java, as the primary language for building apps of all types. However, this book is unlike other Android books in that it doesn’t assume that you already have Java proficiency. This new and expanded second edition of Learning Java by Building Android Games shows you how to start building Android games from scratch. The difficulty level will grow steadily as you explore key Java topics, such as variables, loops, methods, object oriented programming, and design patterns, including code and examples that are written for Java 9 and Android P. At each stage, you will put what you’ve learned into practice by developing a game. You will build games such as Minesweeper, Retro Pong, Bullet Hell, and Classic Snake and Scrolling Shooter games. In the later chapters, you will create a time-trial, open-world platform game. By the end of the book, you will not only have grasped Java and Android but will also have developed six cool games for the Android platform.
Table of Contents (30 chapters)
Learning Java by Building Android Games Second Edition
Contributors
Preface
Index

Rotating Bitmaps


Let's do a little bit of theory before we dive into the code and consider exactly how we are going to bring the snake to life. Look at this next image of the snake's head.

And now look at one of the snake's body segments.

Regarding the body segment, it is a near-perfect circle, it is symmetrical horizontally and vertically through the center. This means that it will look OK whatever way the snake is headed.

The head, on the other hand, is facing right and will look ridiculous when it is headed in any direction other than to the right.

It would be quite easy to use Photoshop or use whatever your favorite image editing software happens to be and create three more Bitmaps from the head Bitmap to face in the other three directions.

Then when we come to draw the Snake we can simply detect which way it is heading and draw the appropriate pre-loaded Bitmap. When you see the code to load and draw the Bitmaps it is my guess that based on your previous experience you will find it simple...