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 a Multitouch UI controller and making it a listener


Create a new package private class and call it UIController.

Note

As already stated, later in the project we will also have another InputObserver based around the player spaceship game object, but we need to do a bit more theory in the next chapter before we can implement that.

Add some class imports, the implements InputObserver code to the class declaration and add the constructor as highlighted next.

import android.graphics.Point;
import android.graphics.Rect;
import android.view.MotionEvent;

import java.util.ArrayList;

class UIController implements InputObserver {

   public UIController(GameEngineBroadcaster b){
        b.addObserver(this);
    }
}

All we need to do in the constructor is call the addObserver method using the GameEngineBroadcaster instance b that was passed in as a parameter. A reference to this class will now be safely tucked away in the inputObservers ArrayList.

Coding the required handleInput method

Add the handleInput...