Building Your First Android Application

More than ever before, the world is mobile. Of this mobile revolution, Android is one of the top platforms. Put out by Google to compete with Apple's iOS, Android shows no signs of slowing down. People are wanting to build the apps that run on Android. You always hear about the success stories of apps getting bought for millions of dollars such as Draw Something or Instagram, and now you can start the path to building your million-dollar idea.

Step 1: Installing Java

Android apps are written in a programming language called Java. Java is one of the most popular programming languages in the world and helps run billions of devices. One of the great things about java is that it is completely free to download. It was originally created by Sun Microsystems, but was purchased by Oracle in 2010. To download java onto your computer go to https://www.java.com/en/ and click on the "Free Java Download" button. This will take you to a page where you can start the download. Once you click the button "Agree and Start Free Download" a file will be downloaded. Once the file is download, run the .exe file. When the install file opens up follow the steps to finish the Java installation.

Step 2: Downloading the Development Environment

There are a number of ways to develop Android apps. The easiest way to get started quickly is to use the ADT Bundle developed by Google. The ADT Bundle provides a number of tools that are essential to building android apps.

To start go to https://developer.android.com/sdk/index.html. Once on this page click on the button "Download the SDK ADT Bundle". Once this button is clicked check the box agreeing to the terms and conditions and select either 32-bit or 64-bit, depending on your computer. After you have agreed and selected your system type click on the "Download the SDK ADT Bundle" button and the download will start. The download is a fairly large .zip file (460 mb) so it may take ahwile. After it has completed downloading you can move on to learn how to install it!

Step 3: Installing the ADT Bundle

With the file done downloading, double-click to open it. Extract all the files to a location on your computer. I left it the default location when I extracted. Once the file is finished extracting click on the file. You should now see two folders named eclipse and sdk and an application called SDK Manager. We are going to open up the environment where you will be developing android apps so click on eclipse. You should now see multiple folders and multiple files. Here you want to double click eclipse.exe to open the application.
With eclipse open we can now get started building our first app!

Step 4: Running the ADT Bundle

When you start up the eclipse you get a screen that asks you wear you want to save your files. Go ahead and leave this default. It should be \path\to\folder\workspace. This is wear all of your files and folders that you create within eclipse will be saved.

Step 5: Building your first App!

After selecting your workspace go to File -> New -> Android Application Project. This brings up a new application window for you to fill out the specs of your app. Type "Hello Wold" into the Application Name space. This will be the name of your application that gets shown in the Play Store when people try to download it. When you fill out the name space all other spaces will automatically fill out with it. When your screen looks like my new application image click next. On the next screen leave everything how it is and click next. On the next screen you can select your apps icon. For now, just leave it set as the default and select next. The next screen has you select an activity. Leave Blank Activity selected and click next. On the final screen keep everything how it is and select Finish. After you click finish your app is now created! Next we show you how to add stuff to the screen.

Step 6: Programming your App

With your new app open, we now want to see how to change what the user will see. The ADT Bundle gives us a great tool with a visual editor to create our apps. To get to this click the activity_main.xml tab that is open. If you do not see it, in the file manager on the left select res -> layout -> activity_main.xml. This opens the visual editor. From the visual editor click on the smaller text "Hello world!" located on the screen. When this is clicked a line to the right under properties highlights. Click on the text @string/hello_world to change it. Your text has to have the @string/ in front of it though. This is a part of the xml so that Android knows what type it is. Play around with the visual editor for a bit. When you finish your app, go on to figure out to test it.

Step 7: Creating the Device to Test Your App

There are two ways that you can test your app. You can either put it on to an android device and run it, or you can set up an emulator to test on. Since not everyone has a device to test on we'll set up an emulator. The youtube video created by user Andr.oid Eric shows how to create an Android Emulator using the Android Virtual Device Manager.

Step 8: Testing Your App

Now that your have your app and you have your device to test it on it's time to put the two together! To test your app on the emulated device you first need to start up your emulated device. My emulated device is a Nexus One so your home screen may look different. When your device is up and running (give it some time, it takes awhile to get started) you then go back to eclipse and click the green play button. Once pushed, eclipse will put your HelloWorld app onto the emulator and run it. Congratulations, you have now created your first android application!

Step 9: Thank you

I hope that the steps were easy to follow and that everything went smoothly. Now that you know how to start developing apps, go out and build your million-dollar idea!