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

Simple array example mini-app


Let's make a simple working array example. You can get the completed code for this example in the downloadable code bundle. It's in Chapter 12/Simple Array Example/MainActivity.java.

Create a project with an empty Activity. Call the project Simple Array Example. Leave the Activity with the default name of MainActivity. It doesn't really matter because we won't be returning to this project.

First, we declare our array, allocate five spaces and initialize values to each of the elements. Then we output each of the values to the logcat window. Add this code to the onCreate method just after the call to super.onCreate().

// Declaring an array
int[] ourArray;

// Allocate memory for a maximum size of 5 elements
ourArray = new int[5];

// Initialize ourArray with values
// The values are arbitrary, but they must be type int
// The indexes are not arbitrary. 0 through 4 or crash!

ourArray[0] = 25;
ourArray[1] = 50;
ourArray[2] = 125;
ourArray[3] = 68;
ourArray[4] = 47...