By S.Bharadwaj 07951A0510 CSE IV A
INTRODUCTION: WHAT IS ANDROID?
Android is a mobile operating system initially developed by Android Inc. Android was bought by Google in 2005. Android is based upon a modified version of the Linux. Google and other members of the Open Handset Alliance collaborated on Android's development and release. The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android. Unit sales for Android OS smartphones ranked first among all smartphone OS handsets sold in the U.S. in the second and third quarters of 2010, with a third quarter market share of 43.6%. The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 79 hardware, software, and telecom companies devoted to advancing open standards for mobile devices. Google released most of the Android code under the Apache License, a free software and open source license. The Android operating system software stack consists of Java applications running on a Javabased, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[ media framework, SQLiterelational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system consists of 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.
Features of Android
Handset layouts Android can adapt to traditional smart phone layouts, as well other VGA, 2D, and 3D graphics libraries.
Storage Android uses SQLite to store all its junk-- I mean, information. Connectivity Android supports a wide variety of technologies, including Bluetooth, WiFi, GSM/EDGE, and EV-DO.
Messaging MMS and SMS are available for Android, as well as threaded text messaging. So you can send as many texties as you like.
Web Browser Android comes pre-loaded with the Web Kit application. Remember, if you don't like it, you can always switch it out for something else later on thanks to the open source nature of the Google Android backend.
Java Virtual Machine Software you write in Java can be compiled in Dalvik Byte codes (say that five times fast. I keep ending up with "Danish light bulb".) These can then be put into a Dalvik Virtual Machine. Basically more robust applications are supported than on some other Mobile Operating Systems.
Media Support Android supports a wide range of audio, video, media, and still formats. MPEG-4, OGG, and AAC are just a few of these. Unfortunately the Media Player as its known right now is pretty basic, although more robust offerings on are the horizon from 3rd Party developers.
Additional Hardware Support Got a touch screen you want to put to its full use? No problem. Android is capable of utilizing outside hardware like GPS, accelerometers, and all that other fun stuff.
Building blocks to an Android application
There are four building blocks to an Android application:
• • • •
Activity Broadcast Intent Receiver Service Content Provider
Activity Activities are the most common of the four Android building blocks. An activity is usually a single screen in your application. Each activity is implemented as a single class that extends the Activity base class. Your class will display a user interface composed of Views and respond to events. Most applications consist of multiple screens. For example, a text messaging application
might have one screen that shows a list of contacts to send messages to, a second screen to write the message to the chosen contact, and other screens to review old messages or change settings. Each of these screens would be implemented as an activity. Moving to another screen is...