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

Using the apple


The Apple class is done, and we can now put it to work in SnakeEngine.

Add the code to initialize the apple object in the constructor at the end as shown.

// Call the constructors of our two game objects
mApple = new Apple(context,
   new Point(NUM_BLOCKS_WIDE,
               mNumBlocksHigh),
               blockSize);

Notice we pass in all the data required by the Apple constructor so it can set itself up.

We can now spawn an apple as shown next in the newGame method by calling the spawn method that we added when we coded the Apple class previously. Add the highlighted code to the newGame method.

// Called to start a new game
public void newGame() {

   // reset the snake


   // Get the apple ready for dinner
   mApple.spawn();

   // Reset the mScore
   mScore = 0;

   // Setup mNextFrameTime so an update can triggered
   mNextFrameTime = System.currentTimeMillis();
}

Next, we can draw the apple by calling its draw method from the draw method of SnakeGame as shown highlighted...