A Short Programming Tutorial on Android (INTRODUCTION)

Introduction

Android is;

1.   a Linux based Operating System for mobile devices

2.   developed by OHA (Open Handset Alliance) led by Google Inc

3.   a rich development platform for mobile applications

4.   free, you can get the SDK (software development kit) without paying anything to anybody

5.   an approachable platform. You can develop apps using various platforms (OSX, Linux, Windows)

6.   getting a lot of attention. Over 10 Billion downloads on Google Play (at the time of writing). Over 500,000 apps have been writted (or ported). Over half a million device activations per day.

The Software Stack

Under the hood of Android is good old Linux--it has been chosen for many reasons, but primarily because of it's stability. Android comes with a lot of libraries (the green boxes on the diagram). You will notice it has SQLite (for database programming), OpenGL (for graphics programming), Webkit (the browser engine that powers Safari and Chrome to name a few) and SSL (for security).

The Android runtime (the blue boxes) consists of (some) core Java libraries and the Dalvik VM. The runtime is not the same JRE/JDK that you have on your desktop. The Android runtime uses a subset of Apache Harmony. Harmony is an open source, free Java implementation from the Apache Software Foundation--the politics of why Android did not use the Oracle reference implementation of the JDK will not be part of this tutorial, I am sure you can find that somewhere else on world wild web.

Android also comes packaged with Application Frameworks--this is the part of the Android that you will see frequently. As an Android developer you will spend a great deal of time reading, studying, implementing and using these frameworks.