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Learning Java by Building Android  Games

You're reading from   Learning Java by Building Android Games Learn Java and Android from scratch by building six exciting games

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Product type Paperback
Published in Aug 2018
Publisher
ISBN-13 9781788839150
Length 774 pages
Edition 2nd Edition
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Author (1):
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John Horton John Horton
Author Profile Icon John Horton
John Horton
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Table of Contents (28) Chapters Close

Preface 1. Java, Android and Game Development FREE CHAPTER 2. Java: First Contact 3. Variables, Operators and Expressions 4. Structuring Code with Java Methods 5. The Android Canvas Class – Drawing to the Screen 6. Repeating Blocks of Code with Loops 7. Making Decisions with Java If, Else and Switch 8. Object-Oriented Programming 9. The Game Engine, Threads, and The Game Loop 10. Coding the Bat and Ball 11. Collisions, Sound Effects and Supporting Different Versions of Android 12. Handling Lots of Data with Arrays 13. Bitmap Graphics and Measuring Time 14. The Stack, the Heap, and the Garbage Collector 15. Android Localization -Hola! 16. Collections, Generics and Enumerations 17. Manipulating Bitmaps and Coding the Snake class 18. Introduction to Design Patterns and much more! 19. Listening with the Observer Pattern, Multitouch and Building a Particle System 20. More Patterns, a Scrolling Background and Building the Player's ship 21. Completing the Scrolling Shooter Game 22. Exploring More Patterns and Planning the Platformer Project 23. The Singleton Pattern, Java HashMap, Storing Bitmaps Efficiently and Designing Levels 24. Sprite-sheet animations, Controllable Player and Parallax Scrolling Backgrounds 25. Intelligent Platforms and Advanced Collision Detection 26. What next? Index

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.

Note

Make sure you deleted 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();

We have an array called mBullets, capable of holding 10000 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.

We also declare and initialize two objects of type Random which we will use to randomly generate screen positions...

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