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)

Polymorphism

We already know that polymorphism means different forms. But what does it mean to us?

Boiled down to its simplest, any subclass can be used as part of the code that uses the superclass.

This means we can write code that is simpler and easier to understand, and easier to modify or change.

Also, we can write code for the superclass and rely on the fact that no matter how many times it is sub-classed, within certain parameters, the code will still work. Let's discuss an example.

Suppose we want to use polymorphism to help write a zoo management game. We will probably want to have a method such as feed. We will probably want to pass a reference to the animal to be fed into the feed method. This might seem like we need to write a feed method for each type of Animal.

However, we can write polymorphic methods with polymorphic return types and arguments:

Animal feed(Animal animalToFeed){
     // Feed any animal here
  ...