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

Summary


This was probably the most technical chapter so far. Threads, game loops, timing try and catch blocks, using interfaces, the Activity lifecycle, etc… It's an awfully long list of topics to cram into 35 pages. If the exact interrelationships between these things are not entirely clear it is not a problem. All you need to know is that when the player starts and stops the game the PongActivity class will handle starting and stopping the thread by calling the PongGame class' pause and resume methods. It achieves this via the overridden onPause and onResume methods which are called by the OS.

Once the thread is running the code inside the run method executes alongside the UI thread that is listening for player input. As we call the update and draw methods from the run method at the same time as keeping track of how long each frame is taking, our game is ready to rock and roll. We just need to add some game objects to update in each call to update and draw in each call to draw.

In the next...