Book Image

Learning Java by Building Android Games - Third Edition

By : John Horton
5 (1)
Book Image

Learning Java by Building Android Games - Third Edition

5 (1)
By: John Horton

Overview of this book

Android is one of the most popular mobile operating systems today. It uses the most popular programming language, Java, as one of the primary languages for building apps of all types. Unlike most other Android books, this book doesn’t assume that you have any prior knowledge of Java programming, instead helps you get started with building Android games as a beginner. This new, improved, and updated third edition of Learning Java by Building Android Games helps you to build Android games from scratch. Once you've got to grips with the fundamentals, the difficulty level increases steadily as you explore key Java topics, such as variables, loops, methods, object-oriented programming (OOP), and design patterns while working with up-to-date code and supporting examples. At each stage, you'll be able to test your understanding by implementing the concepts that you’ve learned to develop a game. Toward the end, you’ll build games such as Sub Hunter, Retro Pong, Bullet Hell, Classic Snake, and Scrolling Shooter. By the end of this Java book, you'll not only have a solid understanding of Java and Android basics but will also have developed five cool games for the Android platform.
Table of Contents (24 chapters)

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 image of the snake's head:

Figure 17.1 – Snake's head

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

Figure 17.2 – Snake's body

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 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...