You're reading from Learning Java by Building Android Games Learn Java and Android from scratch by building six exciting games

Product type Paperback

Published in Aug 2018

Last Updated in Feb 2025

Publisher

ISBN-13 9781788839150

Length 774 pages

Edition 2nd Edition

Languages

Java

Tools

Android

Concepts

Mobile Game Development

Author (1):

John Horton

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Table of Contents (28) Chapters

Preface

1. Java, Android and Game Development FREE CHAPTER

2. Java: First Contact

3. Variables, Operators and Expressions

4. Structuring Code with Java Methods

5. The Android Canvas Class – Drawing to the Screen

6. Repeating Blocks of Code with Loops

7. Making Decisions with Java If, Else and Switch

8. Object-Oriented Programming

9. The Game Engine, Threads, and The Game Loop

10. Coding the Bat and Ball

11. Collisions, Sound Effects and Supporting Different Versions of Android

12. Handling Lots of Data with Arrays

13. Bitmap Graphics and Measuring Time

14. The Stack, the Heap, and the Garbage Collector

15. Android Localization -Hola!

16. Collections, Generics and Enumerations

17. Manipulating Bitmaps and Coding the Snake class

18. Introduction to Design Patterns and much more!

19. Listening with the Observer Pattern, Multitouch and Building a Particle System

20. More Patterns, a Scrolling Background and Building the Player's ship

21. Completing the Scrolling Shooter Game

22. Exploring More Patterns and Planning the Platformer Project

23. The Singleton Pattern, Java HashMap, Storing Bitmaps Efficiently and Designing Levels

24. Sprite-sheet animations, Controllable Player and Parallax Scrolling Backgrounds

25. Intelligent Platforms and Advanced Collision Detection

26. What next?

Index

More Java Collections – Meet Java Hashmap

Java HashMaps are neat. They are part of the Java Collections and a kind of cousin to ArrayList which we have now used in two projects (this will be the third). They basically encapsulate really useful data storage techniques that would otherwise be quite technical for us to code successfully for ourselves.

We will get practical with HashMap in the next section when we discuss a problem regarding storing Bitmap instances in our GameObject instances. HashMap will be the second part (Singletons are the first part) of the solution to this problem.

I thought it would be worth taking a first look at HashMap on its own.

Suppose, we want to store the data of lots of characters from an RPG type game and each different character is represented by an object of type Character.

We could use some of the Java tools we already know about like arrays or ArrayList. However, Java HashMap is also similar to these things but with HashMap we can give a unique key...