The development environment

There are multiple options regarding which software to use when developing Android apps. In the early days of developing Android, an IDE called Eclipse was most commonly used. A few years ago, a new "official" contender for the best Android IDE was released. This was Android Studio. The problem after its first release was that it was still in the beta (not finished) stage. It had numerous bugs, including some quite awkward ones. However, even then it was the preferred IDE for many because of its smooth operation, cool looks, official status, and prestigious heritage.

Now that Android Studio has exceeded version 1, there is virtually no reason to use anything else, especially if you are just getting started with Android. If you already have Eclipse set up for Android development and really don't want to change, that's fine, the code in this book will work. However, there will be significant differences in the instructions, especially regarding the user interface (UI) designer. Also, the code in this book has been thoroughly tested by others and me in Android Studio.

The sections that follow will set up a development environment with the JDK and Android Studio as our IDE of choice.

This can be as simple as downloading, double-clicking on the downloaded file, and following the installation instructions. However, sometimes it isn't. So, it is probably worth running through the installation process step by step and pointing out along the way a few options that can make things easier.

Installing the JDK

As a little bit of preparation before we install the JDK, you need to know which operating system you have and whether it is 32 or 64 bit. If you are unsure, use this little tip to find out.

Tip

Do I have a 32-bit or 64-bit Windows system?

To find out, right-click on My Computer (This PC on Windows 8) icon, left-click on the Properties option, and look under the System heading of the System type entry like this:

Now we are ready to install the JDK. This fairly simple set of steps will set up the JDK quickly. The only slight delay is the download itself, which could take a while on slower Internet connections. The actual installation process should be fast and trouble free:

1. Visit the Java JDK downloads page at http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html.
2. If the link has changed, conduct a web search for Java JDK download. The only potential stumbling block at this stage is that you click on a link for the JRE instead. JDK is what we need. The following is a screenshot of the important part of this page:
   
3. Your download page will most likely be slightly different. There will be a newer version of the JDK by the time you read these words, so the 8u51 will be different. That's OK, we just need whichever is the newest version. Simply click on the Accept License Agreement radio button that is highlighted in the previous screenshot and then click on the download link, which is on the right-hand side column corresponding to your operating system in the Product/File Description column. If you are not sure whether you have 32-bit or 64-bit Windows, refer to the tip before this section.
4. Wait while the JDK is downloaded to your hard drive.
5. In the folder where you've downloaded the JDK, right-click on the jdk-8u51-windows-x64.exe file and select Run as administrator. The precise name of the file you have will vary based on whether you have 32-bit or 64-bit Windows and what the current version of the JDK happens to be at the time.
6. There will be a series of windows that will guide us through the installation process. The most we have to do is just click on Next to proceed. As promised, I will guide you through them one at a time and point out when you might like to make changes or make a note of things. The following is a screenshot of the first window that you will see during the installation:
   
7. Now, click on Next and you will see this window:
   
8. On the window pictured in the previous screenshot, we can leave all the options at their default values. They are just what we need. The Install to setting is worth considering, however. By the time we install the JDK, Android Studio, and all the extra tools and files that come with it, we will have around 6 gigabytes of files and folders. Now, consider that we will also be making lots of projects throughout the course of this book. Ideally, we want all of these files, folders, and projects to be on the same hard drive. They don't have to be, but we might avoid some problems later on if they are. So, do you have at least 6 gigabytes of space on the hard drive that you've chosen by default? If not, you might like to browse to another folder. In addition to this, as we will see later on in this tutorial, it will be handy (but not essential) to simplify the folder names used to install the JDK. So, click on the Change button and you will see this window:
   
9. Browse to the hard drive where you will be installing all of your development tools. Then simplify the names of the folders in which you will install the JDK to just Java\JDK\. As you can see in the next screenshot, I have also switched to my D:\ drive, as I have more space there:
   
10. It actually doesn't matter what you call these folders as long as you remember where they are and what they are called, including whether they are uppercase or lowercase letters. Perhaps you can jot down a note or copy and paste them to a file on your desktop. When you are happy with the chosen installation location and folder names, go ahead and click on Next.
11. The next window will not appear on every installation. If you don't see the window pictured as follows, its fine, you can skip to step 13. If you do see the window, proceed to step 12.
    
12. Understandably, this window could cause confusion if you have never done any Java development before. You might be thinking that we had already chosen the destination folder for Java. We chose the location for the JDK. This window refers to the bog-standard Java—the JRE. This is what runs Java programs on your PC and, since we are developing for Android, we don't need it. However, we still need to choose a location in order to proceed. Accept the default and just click on Next. If you are a tidiness obsessive like me, you can change to the same Java folder from step 8 and then click on Next.
13. Next, you will see the window that says 3 Billion Devices Run Java. Android has over 1.1 billion devices alone at the time of writing this despite a slow start in 2015. You might also like to know that there are more than 18,000 different distinct devices. Seriously, Google it if you think it sounds crazy. You can do this while you wait for the installation to complete.
    
14. Now, you will see the final screen. Click on Next Steps if you are curious, but there is no need because we will be covering Android-specific next steps without delay.
    
15. Click on Close, and we are almost done installing the JDK, with just a few more precautionary steps left.
16. Now, we will make sure that Windows (and all its applications) know where to find the JDK. Right-click on your My Computer (This PC on Windows 8) icon and Properties | Advanced system settings | Environment Variables | New (under System variables and not under User variables). Now you can see the New System Variable dialog as follows:
    
17. As shown in the previous screenshot, type JAVA_HOME in Variable name and enter D:\Java\JDK in the Variable value field. If you've installed the JDK somewhere else, then the file path you enter in the Variable value field will need to point to where you've placed it. Be sure to type it correctly, make sure that the slashes \ are the right way around, and don't add any extra slashes.
18. Click on OK to save your new settings. Now, click on OK again to clear the Advanced system settings window.

We have successfully installed the JDK, which we need to develop Android apps with Android Studio, and we have also installed the JRE, if it wasn't installed already, which we won't be using, but this won't cause us any problems either.

Now that the JDK is installed and ready to go, we are only one step away from building our first Android app. Installing Android Studio can take a bit longer than the JDK and is a little more nuanced, but it is nothing a determined, aspiring, developer won't be able to handle with ease.

Now that we know what to expect, we can get on with the installation of Android Studio. Follow the given steps to do so. There is nothing especially tricky about this, and the few aspects that might need some consideration will be discussed as they arise:

This was a fairly lengthy tutorial but, hopefully, it wasn't too tough. Android Studio and the supporting tools that we need are installed and ready to go. We are really close now to building our first app.

First, let's look at the composition of an Android app a little.