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

The object specifications


Now we know that all our game objects will be built from a selection of components. Sometimes the components will be unique to a specific game object but most of the time the components will be used in multiple different game objects. We need a way to specify a game object so that the factory class knows what components to use to construct each one.

First, we need a parent specification class from which all the other specifications can derive so we can use them all polymorphically and not have to build a different factory or different methods within the same factory for each type of object.

Coding the ObjectSpec parent class

This class will be the base/parent class for all the specification classes. It will have all the required getters so the factory class can get at all the data it needs. Then, as we will see shortly, all the classes that represent real game objects will simply have to initialize the appropriate member variables and call the parent class's constructor...