Getting started with Android

Posted by s.hettrick on 1 November 2011 - 2:48pm

By Stefan Freitag, European Grid Infrastructure.

With some predicting that the app market will be worth $25 billion by 2015, there has been a lot of interest in developing for Android and the iPhone. We recently reported on GridAcro, an Android app that allows a user to search through the huge number of abbreviations used in Grid computing and presents a definition and further information. We asked Stefan Freitag, the developer of GridAcro, to give us a quick overview on getting started with developing for Android.

Grid computing is a complex topic, and before you can become an expert, you have to become familiar with many acronyms and abbreviations. I created an app for Android-based smartphones, called GridAcro, which is browsable list of about 650 grid computing terms with their definitions and links to further information.

Before I started to implement GridAcro I had to set up a development environment and test it with the (obligatory) Hello Android! app. A part of this environment is the Android SDK (Software Development Kit), which is available for various platforms (Microsoft Windows 7, Mac OS X, Linux) and can be downloaded from the android website. After extracting the software archive, it is recommended to check for available updates using the commands:

tar xzf android-sdk_r15-linux_x86.tgz cd android-sdk-linux_x86 ./tools/android update sdk

Since the SDK is available locally, I needed an IDE (integrated development environment). Eclipse seemed to be a pretty good choice and (since version 3.5) it is supplied with an ADT plug-in (Android Development Tool). To install the plug-in, a new repository must be added to Eclipse:

Help -> Install New Software -> Name: ADT Plug-in, Location: https://dl-ssl.google.com/android/eclipse/

Select Developer Tools and install them. After restarting Eclipse, the Android SDK Manager and AVD Manager (Android Virtual Device) items are available in the Windows menu. The AVD Manager helps you to set up the Android emulator by defining hardware and software options. Defining at least one AVD is mandatory, because your app will be executed on an AVD. Before making use of the Developer Tools, the path to the Android SDK has to be configured:

Window -> Preferences -> Android -> SDK Location

With the SDK and the ADT installed, you are ready to implement the Hello Android! app. Good documentation is available on the android website.

You must sign the app with your certificate to create a trust relationship between you and the end user:

keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -validity 10000

Once you are satisfied with your app, the next question is: how can it be transferred to your smartphone? Two options exist:

Export your app via Eclipse as an apk (Android application package) and copy it to your smartphone, for example, using the USB interface. After copying the application package to the smartphone, it has to be installed.
Make your app public by uploading it to the Android app market and distribute it from there.

The second options mentioned requires your registration as a developer at the Android market. There is a one time registration fee of $25. Additionally, if you want to sell your app, you have to setup a Google Checkout Merchant account as well