Welcome to Learning Java by Building Android Games, which I hope is just the
beginning of your exciting journey into designing and writing games. By the
end of this book, we will have made four complete games: a math quiz with
dynamically increasing dificulty, a memory game in the style of the classic
Simon toy, a pong-style squash game, and a clone of the classic Snake game.
Besides these games, we will build more than a dozen working apps to practice and
demonstrate individual concepts to aid our learning of Java, Android, and games.
Our games and apps will feature sound FX, graphics, and animations. We will learn
everything from using the standard Android User Interface (UI) designer to creating
smooth animations by plotting individual pixels.
Although I will encourage you to work with me and implement the speciic projects
that are detailed step by step throughout the book, I fully expect that once you grasp
the different concepts, you will want to use them in your own unique creations
without delay. This is exactly what I hope you will be inspired to do.
The game projects themselves are not the objective of the book but the means to a
much loftier goal. By the end of the book, you will be able to design and implement
your own 2D Android games, to sell or just to give away, on Google Play.
There is a bit of ground work to cover irst, but I promise it
won’t take long and it won’t be complicated either. Anyone
can learn to program.
Why Java, Android, and Games?
[ 8 ]
However, there are so many differing opinions among experts, which breeds
confusion among beginners concerning the best ways of learning to program. So it
is a good idea to look at why learning Java, Android, and games is an ideal pathway
for beginners. This will be the irst thing we will discuss in this book.
Here is what we will learn in this chapter:
• Is this book for me?
• Why should I use games to learn to program?
• Why should I learn Java and Android?
• Setting up our development environment
Is this book for me?
If you have already decided that Java, Android, or games are what you want to
learn, then the next question might be, “Is this speciic book for me?”.
There are plenty of Java books for beginners and books by much more accomplished
authors and programmers than myself. I have read many of them and admire the
authors. However, when these books drift away—which they all do—to topics such
as Java-native interfaces, web browser applets, or server-side remote communication,
I sometimes ind myself questioning their immediate relevance to me.
At this point, at least subconsciously, my commitment would wane and the learning
process would slow or stop.
If you just want to learn pure Java
If you just want to learn Java on its own, this book will be a solid start. Although the
Android stuff might be considered overhead to your pure Java learning, this is much
less than the multitude of potentially unnecessary topics that would be introduced
in any other Java book. The only caveat with this book is that the necessary overhead
is all at the beginning. But once this minimal overhead is cleared, we can focus quite
intently on Java.
With regard to the amount of overhead:
• It will take about six pages to set up our programming environment in
• It will take Chapter 2, Getting Started with Android, to get familiar with the
Android tools, create your irst working project, and glimpse your irst real
• From then on, it will be nearly pure Java and building games
[ 9 ]
You will soon see that the tiny amount of overhead is not excessive and is
If Android is your focus
If it was Android itself that made you look at this book, then I am proud to say this is
the irst book that will teach you Android without assuming you have any prior Java
or programming knowledge whatsoever.
Where this book will take you
By the end of this book, you will be able to easily take one of many paths
• Learning Java at a higher level for any platform
• Intermediate level Android learning including pure game frameworks
(which will be covered in more detail in Chapter 9, Making Your Game the
Next Big Thing)
• A higher level of games development
• Much easier tackling of any modern object-oriented language for things
such as iOS, Windows, or web development
So if you know you want to learn Android or Java, hopefully, I have gone some way
to make you commit to the way this book will help you. But why games, Android, or
Java at all?
Why build games to learn to program?
Fun, of course! But there are other reasons too. Successfully running any program
we have written is immensely satisfying, even more so when it involves using some
code that we previously didn’t understand.
But making our own games, as you will soon realize, creates a feeling of pleasure
that is not easy to describe—it has to be experienced. Then there are added bonuses
of sharing our creations with friends on a phone or tablet or even sharing them
publicly on the Google Play Store, and you might realize that once you start making
games, you can’t stop.
As we create more complex games steadily, you’ll realize that all techniques and
pieces of code can be rehashed to create other games, and you can then start
planning your very own unique masterpieces. This is exhilarating to say the least.
Why Java, Android, and Games?
[ 10 ]
And as with many subjects, the more we practice the better we get. So games are a
perfect way to start learning to program Java. However, most beginners’ books for
Android games require a fairly high level of Java knowledge. But as we will see, it is
perfectly possible to keep the practical examples as fun game projects and still start
with the very basics of Java.
There is a slight trade-off in doing things this way. We will not always approach the
working game examples in a “by-the-book” manner. This is to avoid the problem of
doing cartwheels before mastering the forward roll.
The learning outcome priority will always be the Java programming concept,
followed by understanding the Android environment and game design principles.
Having said that, we will closely examine and practice plenty of Android and game
Of course, from what we have just discussed, you can probably surmise that it would
have been possible to teach a bit more Java in the same number of pages if we hadn’t
been making games.
This is true, but then we lose all the beneits that come with using games as the
subject matter. Making games really can be a joy, and when our brains are open and
eager for information, we will learn much faster. The minimal overhead of learning
this way is negated a hundred times over. If games don’t interest you in the slightest,
then there are plenty of Java beginners’ guides out there that take the traditional
approach. Just don’t expect quite the same thrill as when you publish your irst
game with online leaderboards and achievements.
Why Android and Java?
A part of successful learning is the commitment by the student, not just to do the
work, but in their belief that they are doing the right thing in the right way. So many
technology-based courses and books don’t get that commitment from the reader, not
The problem is the students’ belief that they might be, partly at least, wasting their
time with something that is or will soon become outdated or perhaps is not quite
right for them. This can be true to a large extent with programming. So why
should you spend your inite time learning Java, on Android?
[ 11 ]
Android is the fastest evolving and growing
At one time, Android updates emerged almost every two months. Even now, they
emerge about once in six months. By comparison, Windows takes years between
versions and even iOS updates come only yearly and usually change relatively
little between versions. Android is obviously evolving and improving at an
Look at the history of Android versions since Version 1 at
The irst humble version of Android was released in 2008, around the same time
when consumers were already quite excited about the then much lashier iPhone.
News stories were also reporting that developers were getting rich by selling apps
in the iTunes app store.
But in the last full year before this book was written, Samsung alone shipped more
Android units than Apple sold all iOS devices combined. I am not joining the war
on whose devices are best. I enjoy aspects of both Android and Apple, but purely
in terms of picking a platform to learn on, you are probably in the right place at the
right time with Android.
Android developers have great prospects
Now you might have picked up this book just for the fun and satisfaction that comes
with learning to program games. But if you decide to develop your learning further,
you will ind that the demand for Android programmers is enormous and therefore
very lucrative too.
Some data suggests salaries in excess of 100,000 US dollars. For
more information, go to http://www.indeed.com/salary?
Why Java, Android, and Games?
[ 12 ]
Android is open source
What open source means is that although Google develops all the lavors of Android
that are used on the newest devices, once the code is released, anybody can do
whatever they like with it. Google only exerts control for a limited amount of time.
In practice, most Android users have the pure Google OS or the modiied
versions turned out by big manufacturers such as Samsung and HTC, but there
is nothing to stop anybody taking the OS and changing, adapting, or converting
it into whatever they like. In short, Android could never be taken away from the
Java is here to stay
Okay, so we see Android isn’t likely to disappear but could Java become redundant?
And will your signiicant time investment be wasted? On Android, as with most
platforms, you can use many languages and tools. Android, however, was designed
from the ground up to facilitate Java development. All other languages and tools are
not invalid but tend to serve a fairly speciic purpose, rather than be a real alternative
to Java. In fact, as far as games are concerned, many of the alternatives to a pure
Java development environment are also Java-based and require a good level of skill
in Java to use. For example, the popular LibGDX game development library, which
allows you to simultaneously make games for Android, iOS, Windows, Linux, Mac
and even the Web, still uses Java! We will talk more about this in Chapter 9, Making
Your Game the Next Big Thing. The point is that Java and Android are tied together
and will likely thrive together.
Java is not just for Android
Java has been around a lot longer than Android, since the beginning of the 1990s in
fact. Although what Java has been used for has evolved and diversiied over more
than two decades, the originally implemented strengths of the language itself remain
the same today.
Java was designed to be platform- or computer-independent. This is achieved by the
use of a virtual machine (VM). This is a program written in another language that
decodes the Java program that we write and interacts with the computer platform
it is running on. So as long as there is a VM for the computer you want to run your
Java program on, with a few caveats, your Java program will work. So if you learn
Java, you are learning a language that is used everywhere from the smart fridge to
the Web and most places in between.
[ 13 ]
It is true, however, that the VM on each platform can and usually does implement
features to speciically suit the uses it is likely to be put to. A clear example of this
would be mobile-device-speciic features such as sensors, GPS, or the built-in camera
on many Android devices. Using Java with Android, you can take photos, detect
the air pressure, and work out exactly where in the world you are. Most fridge VMs
probably will not do this. So you can’t always just run a Java program designed for
device x on device y, but the language and syntax is the same. Learning Java on
Android prepares you in a large part for Java in any situation. So rest assured that
Java isn’t going away any time soon.
Java is fast and easy to use
There is a decades-long debate over which language is the best overall or which
language is the best to learn programming. Critics of Java will likely say things
about Java’s speed. It is true that the Java memory management along with the
VM interpretation process does have some speed cost. However, these things have
beneits; they signiicantly improve our productivity and the way that the Android
VM interacts with a device largely negates the minor speed penalty. And since
Android 4.4, it does so completely with Android Run Time (ART), which installs
apps written in Java as fully native applications. Now Java programmers can build
games in a friendly, interpreted language and have them run as if they were written
in a more challenging natively compiled language.
A summary of Java and Android
In a rapidly changing world, if you are worried about where to invest your precious
learning time, it is hard to have more conidence. Here we have a language (Java)
whose fundamentals have remained almost the same for nearly a quarter of a
century, and a platform (Android) that is backed by the biggest names in hardware,
software, and retail, and though it’s admittedly hugely inluenced, it’s not actually
owned by anyone.
I am not an evangelist of any technology over another although it is true that I love
doing stuff on Android. But you can be sure in your mind that if you are considering
the best path to begin learning programming, there is a very strong argument that
Java and Android are the best choice.
If you want to learn Java for any of its numerous uses, then this is a very good place
to start. If you want to develop for Android or get into Android development of any
sort, then Java is the absolute fundamental way to start, and making games has the
enormous beneits we have already discussed.
Why Java, Android, and Games?
[ 14 ]
By the end of the book, you will be able to write Java code for almost any
Java-supported platform. You will be able use almost everything you learn
in this book, away from the Android environment.
If you are planning to pursue a career or business by making Android games or any
Android apps, then this book is possibly the only place to start for beginners.
If you are completely new to Java and want the easiest possible path to mastering
it—the fastest growing platform on the planet—then Learning Java by Building
Android Games will probably be just right for you.
So hopefully you are assured that the path this book will take to learn Java is as
easy, fun, and thorough as learning Java can be. Let’s get set up so we can start
Setting up our development environment
The irst thing we need to do is prepare our PC to develop for Android using Java.
Fortunately, this is made quite simple for us.
If you are learning on Mac or Linux, everything in this book
will still work. The next two tutorials have Windows-speciic
instructions and screenshots. However, it shouldn’t be too
dificult to vary the steps slightly to suit Mac or Linux.
All we need to do is:
1. Install a software package called the Java Development Kit (JDK), which
allows us to develop in Java.
2. Install Android Studio, a program designed to make Android development
fast and easy. Android Studio uses the JDK and some other Android-speciic
tools that automatically get installed when we install Android Studio.
Installing the JDK
The irst thing we need to do is get the latest version of the JDK. To complete this
guide, perform the following steps:
1. You need to be on the Java website, so visit http://www.oracle.com/
[ 15 ]
2. Find the three buttons shown in the following screenshot and click on the
one that says JDK (highlighted). They are on the right-hand side of the web
page. Click on the DOWNLOAD button under the JDK option:
3. You will be taken to a page that has multiple options to download the JDK.
In the Product/File description column, you need to click on the option that
matches your operating system. Windows, Mac, Linux and some other less
common options are all listed.
4. A common question here is, “do I have 32- or 64-bit windows?”. To ind out,
right-click on your My Computer (This PC on Windows 8) icon, click on the
Properties option, and look under the System heading in the System type
entry, as shown in the following screenshot:
5. Click on the somewhat hidden Accept License Agreement checkbox:
Why Java, Android, and Games?
[ 16 ]
6. Now click on the download option for your OS and system type as
previously determined. Wait for the download to inish.
7. In your Downloads folder, double-click on the ile you just downloaded. The
latest version at time of writing this for a 64-bit Windows PC was jdk-8u5-
windows-x64. If you are using Mac/Linux or have a 32-bit OS, your ilename
will vary accordingly.
8. In the irst of several install dialogs, click on the Next button and you will see
the next dialog box:
9. Accept the defaults shown in the previous screenshot by clicking on Next.
In the next dialog box, you can accept the default install location by clicking
10. Next is the last dialog of the Java installer. Click on Close.
The JDK is now installed. Next we will make sure that Android Studio is able
to use the JDK.
[ 17 ]
11. Right-click on your My Computer (This PC on Windows 8) icon and
navigate to Properties | Advanced system settings | Environment variables
| New (under System variables, not under User variables). Now you can
see the New System Variable dialog, as shown in the following screenshot:
12. Type JAVA_HOME for Variable name and enter C:\Program Files\
Java\jdk1.8.0_05 for the Variable value ield. If you installed the JDK
somewhere else, then the ile path you enter in the Variable value: ield
will need to point to wherever you put it. Your exact ile path will likely
have a different ending to match the latest version of Java at the time you
13. Click on OK to save your new settings. Now click on OK again to clear the
Advanced system settings dialog.
Now we have the JDK installed on our PC. We are about half way towards starting
to learn Java programming, but we need a friendly way to interact with the JDK and
to help us make Android games in Java.
We learned that Android Studio is a tool that simpliies Android development and
uses the JDK to allow us to write and build Java programs. There are other tools
you can use instead of Android Studio. There are pros and cons in them all. For
example, another extremely popular option is Eclipse. And as with so many things
in programming, a strong argument can be made as to why you should use Eclipse
instead of Android Studio. I use both, but what I hope you will love about Android
Studio are the following elements:
• It is a very neat and, despite still being under development, a very reined
and clean interface.
• It is much easier to get started compared to Eclipse because several Android
tools that would otherwise need to be installed separately are already
included in the package.
Why Java, Android, and Games?
[ 18 ]
• Android Studio is being developed by Google, based on another product
called IntelliJ IDEA. There is a chance it will be the standard way to develop
Android in the not-too-distant future.
If you want to use Eclipse, that’s ine; all of the code in this
book will work. However, some the keyboard shortcuts
and user interface buttons will obviously be different. If
you do not have Eclipse installed already and have no
prior experience with Eclipse, then I even more strongly
recommend you to go ahead with Android Studio.
Installing Android Studio
So without any delay, let’s get Android Studio installed and then we can begin our
irst game project. To do this, let’s visit https://developer.android.com/sdk/
1. Click on the button labeled Download Android Studio to start the Android
studio download. This will take you to another web page with a very
similar-looking button to the one you just clicked on.
2. Accept the license by checking in the checkbox, commence the download by
clicking on the button labeled Download Android Studio for Windows, and
wait for the download to complete. The exact text on the button will probably
vary depending on the current latest version.
3. In the folder in which you just downloaded Android Studio, right-click on
the android-studio-bundle-135.12465-windows.exe ile and click on
Run as administrator. The end of your ilename will vary depending upon
the version of Android Studio and your operating system.
4. When asked if you want to Allow the following program from an unknown
publisher to make changes to your computer, click on Yes. On the next
screen, click on Next.
5. On the screen shown in the following screenshot, you can choose which users
of your PC can use Android Studio. Choose whatever is right for you as all
options will work, and then click on Next:
[ 19 ]
6. In the next dialog, leave the default settings and then click on Next.
7. Then on the Choose start menu folder dialog box, leave the defaults and
click on Install.
8. On the Installation complete dialog, click on Finish to run Android Studio
for the irst time.
9. The next dialog is for users who have already used Android Studio, so
assuming you are a irst time user, select the I do not have a previous version
of Android Studio or I do not want to import my settings checkbox, and then
click on OK:
That was the last piece of software we needed. The simple nine-step process we just
went through has actually set up a whole range of Android tools that we will begin
to use in the next chapter.
Why Java, Android, and Games?
[ 20 ]
We discussed why games, Java, and Android are not only extremely exciting but
also arguably the best way to learn to program. This is because games can be an
extremely motivating subject matter and Java and Android have enormous strengths
with regards to popularity and longevity, and are open to all of us to use for free.
We also set up the Java development kit and installed Android Studio, getting ready
for the next chapter where we will actually create a part of a working game and take
our irst look at some Java code.