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Tuesday, 4 September 2012

ANDROID INTRODUCTION




What is Android ? 


“Android is a software stack for mobile devices that includes an operating system, middleware and key applications”. 
In other words, Android is a software bunch comprising not only operating system 
but also middleware and key applications.



History Of Android 


Android, Inc. was founded in California , United States in October, 2003 by Andy Rubin, Rich Miner , Nick Sears and Chris White to develop smarter mobile devices. 

On August , 2005 GOOGLE acquired Android Inc. making Android Inc. a wholly owned subsidiary of Google Inc. 



History Of Android 

At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel In 2007, the Open Handset Alliance a consortium of several companies which included Google, HTC, Intel,LG,Motorola , Samsung, T-Mobile etc was announced.The goal of the Open Handset Alliance is to develop open standards for mobile devices.In 2008, 14 new members joined, including Sony Ericsson, Toshiba Corp, and Vodafone Group. 

As of today OHA is group of 84 companies. 



Android Market Share 

•Android has captured a market share of 53% and is the topmost smartphone 

•iOS of Apple is at second position with 29% 
•Blackberry holds third spot with 10% 
•Windows phone 7 holds 2% 



 
Versions Of Android 

Platform Codename :


.Android 1.5 Cupcake 

.Android 1.6 Donut 
.Android 2.1 Eclair 
.Android 2.2 Froyo 
.Android 2.3 
.Android 2.3.2 Gingerbread 
.Android 2.3.3 
.Android 2.3.7 
.Android 3.0 Honeycomb 
.Android 3.1 
.Android 3.2 
.Android 4.0 
.Android 4.0.2 Ice Cream Sandwich 
.Android 4.0.3 


 

Android Devices 

Android devices come in all shapes and sizes. The Android OS can be seen powering the following types of devices: 


. Smartphones 

. Tablets 
. E-reader devices 
. Netbooks 
. MP4 players 
. Internet TVs 



What is Android Market ? 

Android Market(now called google play is an online software store developed by Google for devices running the Android operating system. It can be accessed via an application program called "Market", preinstalled on most Android devices, which allows users to browse and download mobile apps published by third-party developers. 




Monetary Benefits 

Developers may sell applications on the Android Market 

Application developers receive 70% of the application price. The remaining 30% is distributed 
among carriers and payment processors.Google itself does not take a percentage. 



Architecture Of Android 

 

Android Architecture Explained 
The architectural diagram shows that the Android platform can be broken down into 4 sections: 

Operating system 

Middleware libraries 
Application framework 
Applications 







Architecture Details 

Operating System: At the very bottom of the Android stack is the operating system. 

Android's OS is Linux based and performs tasks similar to a desktop computer OS. This 
includes: 

.Interfacing with the hardware through a set of device drivers (such as audio or video drivers) 

. processing user input 
.managing application processes, handling file and network I/O, and so forth 


Middleware Libraries: The middleware includes libraries for many functions (data storage, graphics rendering, web browsing, and so on) and it also contains a special sub-section called the “Dalvik runtime.” 


This is Android's special non standard JavaVirtual Machine (JVM) and its core Java application libraries 



Application Framework: 


framework, as we know is a set of basic tools which help a developer to build more complex tools. The developers can access all framework APIs and manage phone’s basic functions like resource allocation, switching between processes or programs, telephone applications, and 

keeping track of the phone’s physical location. 


Applications: 


There are 4 different types of applications available on most Android devices: 

.core open source applications that are included as part of Android itself, such as the Browser, Camera, Gallery, Music,Phone proprietary Google apps that are not open source which are included with most official builds, including: Market, Gmail, Maps, YouTube and more handset manufacturer specific applications that are included on specific builds (such as AT&Ts own music player, Verizon's own Navigator, or Sprint's TV) third party applications that are available in the Android Market 






Android Development Process 


.java files 

.class files 
.dex (Dalvik executables) 
.XML file,Image files 
.apk file (Android package) 
.aap(android asset packaging) 




Android applications are primary written in the Java programming language. The Java source files are converted to Java class files by the Java compiler.Android provides a tool dx which 
converts Java class files into a dex (Dalvik Executable) file. All class files of one application are placed in one compressed .dex file. 



The .dex file and the resources of an Android project, e.g. the images and XML files are packed into an .apk(Android Package) file. The resulting .apk file contains all necessary data to run the Android application and can be deployed to an Android device