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)

Spawning an array of bullets

Now we know the basics of arrays we can get started spawning a load of bullets at the same time and store them in an array.

Tip

Make sure you delete the temporary code from the Spawning a bullet section before proceeding.

Add a few control variables and declare an array of bullets as a member of BulletHellGame. Add this code just before the constructor:

// Up to 10000 bullets
private Bullet[] mBullets = new Bullet[10000];
private int mNumBullets = 0;
private int mSpawnRate = 1;
private Random mRandomX = new Random();
private Random mRandomY = new Random();

Important note

You will need to add the Random class: import java.util.Random;.

We have an array called mBullets, capable of holding 10,000 bullets. The new keyword initializes the array, not the Bullets within the array. We also have two int variables to keep track of how many bullets we want to spawn each time the spawn method is called and how many bullets there are in total.

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