Now that the basics have been covered in the previously, we can go on to the finer details of developing the app.

We first start with the Android SDK or the Standard Development Kit. This is what helps you install the package to develop your app. These packages basically contain methods that will help you develop your app which are specific to each Android version.  As you start it, it’ll give you a whole list of Android OS versions, both current and obsolete. Now you have to be very specific when selecting the version as the app developed for a lower version(say version 2.2) will not work for a higher version (say 4.1). This is because, as given in the example Android version 4.1 would have methods that 2.2 has but vice versa is not true.

So installing one package can take at least half an hour. The latest version of the SDK will install both the package and the Google API, which will come in use later on as you develop it android app development. It also gives you sample for your code.

After the installation we go on to the coding part. This is where Eclipse comes in. But as it supports only Java, it’ll help you a lot to be well versed with that language. When working on Eclipse the first thing you have to do is set your preference from general to Android. For Windows users, this option will be there in the drop down list named “Windows” but for Mac users it will be present in the drop down list of “File”. In the “Preference” option when you select Android, you need to make sure that the Google API and the Android package that you selected are there in the window on the Right Hand Side. If not, you will have to browse for them from the folder named SDK.

After setting this up you can go on to starting a new project in Eclipse. When you do, you will have to select an Application name, a Project name and a Package name. The Application name and the Project name need to be a single word otherwise it will not be accepted. More important than that is the Package name. You have to be very careful in making sure that it is unique, otherwise it will not be published or worse, it might go to someone else having the same name. And while feeding in the package name, you must ensure that the name has dot (.) in it. Following this, you can begin coding your app.

To code your program you also need to know XML or Extensive Markup Language. XML is a markup language that defines a set of rules for encoding documents in a format that is both human readable and machine readable. It will come in use when you design the layout of your app. It is relatively easy to learn and there are many sites that provide free tutorials for XML. The advantage of using XML is that if you do not wish to spend your time coding the layout, the Graphical Layout option can be used to interact with the layout and you can edit the whole thing graphically while the code changes by itself according to your actions.

Then we go on to the emulator. The Emulator can be started from the “Android Virtual Device Manager” present in the “windows” dropdown list for Windows users and under “File” for Mac users just like in the case of Preferences.  When the emulator starts a pop up window will first ask you to specify the dimensions. The emulator is what will help you figure out if your program is working by behaving exactly like the phone would.

Now we go on to the hard part, which is the source code. This is also where the magic happens. Here you use Java to write the main program. You can access it from the options in the window on the Left Hand Side of the main Window. Here you will also find the option to view the Gen Code. It is advised not to make any changes to that as it can cause unforeseeable problems with your program. So we only stick to the source code while making the app. In the same window you will also find Jar. This is the option that helps you make the app interactive and define how your app will respond to touch, slide and tilt.

In the bin you have another option named RES which stands for resources and all the coding in RES in done using XML. The drawables in this option are not under the control of the programmer as it is the phone that decides the resolution of the app according to its capabilities after the app is transferred to the phone. It also has the option that would allow you to put in the sound track of your app. Extra care have to be taken while putting in a soundtrack as the video and sound of the app could go out of sync if there is any lag in the program. Most programmers make a separate folder for the soundtrack instead of linking the soundtrack to the program itself to prevent the app from getting slow.

Now that you are intimate with the entire process of building an Android app you can very well implement your knowledge of Java and XML to build your very own Android app.