Rob Thompson

If you’ve ever had an inkling to get into mobile software development, now is your time. Google has drastically narrowed the gap for wanna-be mobile developers to get into this arena with their opensource and free Android SDK (Software Development Kit). Exciting new phones such as the, HTC “Google Phone”, Motorola Droid, Motorola Cliq and MyTouch are making a splash and diverting attention away from the all-consuming iPhone market.

Android does have a bit of an identity crisis going on, no doubt because of the openness of the platform and the freedom it provides to developers hoping to capitalize on it. The marketing buzz surrounding different phones and software like Droid, MyTouch, G1, Google Phone, MOTOBLUR, Android, etc. seem to have a lot of people disoriented and on the surface, it is a bit confusing. All of these products are really only variously branded versions of a base Android OS running on a phone with some custom apps pre-installed. Android apps that you write will generally work on all of these. Here’s a breakdown:

The Android SDK is available for free to download and so is Eclipse and Java. The Android OS is based on a Linux kernel and the Android GUI and API are written in Java. You can get the development environment running under MacOS X, Windows and Linux and the included documentation is excellent. Java is what enables the Android application packages (.apk files) to be installed on any architecture phone. A comprehensive development environment built on top of Eclipse allows you to visually draw the layout for your Android app, then fill in the blanks with a mix of more Java and XML. A variety of libraries built into the Android API such as Apache HTTP libs make interacting with web-based services over cell networks very easy. Also unlike Apple, a complete “service” infrastructure allows you to write daemons/services that run in the background with ease. Android incorporates the lightweight opensource database system SQLite to deal with local data storage and includes a basic library much like a registry for storing application preferences and restoring previous states of apps.

public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);	   	   
  TextView tv = new TextView(this);
 
  tv.setText("sun3.org says hello!");
  setContentView(tv);
 
  // Start my custom service, if it is not running already
  startService(new Intent(this, AndroidConnectService.class));
  }

Within the SDK, you first need to become familiar with the terminology. For example, the GUI that you write is called an “Activity”, “Intents” are actions along with data (calls to activities/services) and the presentation/screen is a “Layout”, etc. Once you get familiar with the basic terminology of the Android SDK and poke around a little, a design philosophy in Android emerges regarding the sharing of access to your interfaces and services. The entire platform is designed to be very modular and to allow other developers to use your Activities and Services.

You don’t even need an Android phone to start your development, as the SDK comes with a complete emulator that lets you test your apps without the pain of installing your software on actual Android hardware every time you make a change. Incidentally, this is also a great way to test-drive Android without buying a phone or borrowing your friend’s phone.

Once you are ready to test out your app on a real phone, you’ll find that the Android OS allows you to download and install your .apk file directly from a web URL. Unlike Apple, the philosophy around Android app development is one of un-restricted access. Apple has a more restrictive App Store, and hackers need to “jail break” their phones before they can install non Apple-approved apps. Apple is only making it harder to jail break their phones. Presumably, Apple is trying to save people from themselves and their own distaste. Google has a different philosophy for Android, whereby they make the SDK components, the OS and source for the whole platform freely available and open to tinkering. It’s surprisingly easy to get an app working, tested and installed on your off-the-shelf Android phone. I had their included “helloworld” example running within about an hour, including downloading the SDK/Java JRE, poking around, compiling, testing on their emulator and installing on my regular phone.

So now you’re wondering where the $25 dollars comes in? The Android Marketplace asks $25 for you to become an official developer. This includes the ability to both upload and sell applications in the official Android Marketplace, which is akin to the Apple AppStore. Unlike Apple, there is little to no review (read “censoring”) of the apps that you sell at the Google Android Marketplace. The $25 is just to keep the spammers away. So, what are you waiting for? =)