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

Generating random numbers to deploy a sub


We need to deploy a sub' in a random position at the start of each game. There are, however, many possible uses for random numbers as we will see throughout this book. So, let's take a close look at the Random class and one of its methods nextInt.

The Random class and the nextInt method

Let's have a look at how we can create random numbers and later in the chapter we will put it to practical use to spawn our sub'. All the demanding work is done for us by the Random class.

Note

The Random class is part of the Java API which is why there is a slightly different import statement to get access to it. Here is the line we added in chapter two.

import java.util.Random;

Note that this is the only import statement (so far) that starts with java… instead of android….

First, we need to create and initialize an object of type Random. We can do so like this:

Random randGenerator = new Random();

Then we use our new object's nextInt method to generate a random number...