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

Coding the Bat input handling


You probably remember we saw the onTouchEvent method in the Sub' Hunter project. It was provided by the Activity class. In this project, however, the input handling is not in the Activity class. If it were we would need to somehow share values between PongActivity and PongGame and things might get into a bit of a muddle. Fortunately, the onTouchEvent method is also provided by SurfaceView which PongGame extends (inherits from).

This time we will make our code a little bit more advanced to handle left, right and stop as well as to trigger setting mPaused to false and start the game.

Add all the code at once and then we will dissect it and discuss how it works. Be sure to read the comments.

// Handle all the screen touches
@Override
public boolean onTouchEvent(MotionEvent motionEvent) {

   // This switch block replaces the
   // if statement from the Sub Hunter game
   switch (motionEvent.getAction() &
               MotionEvent.ACTION_MASK) {

          //...