android os.doc

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ABSTRACT

The unveiling of the Android platform on was announced with the

founding of the Open Handset Alliance, a consortium of 48 hardware, software, and

telecom companies devoted to advancing open standards for mobile devices. Google

has made most of the Android platform available under the Apache free-software and

open source license.

Android is a freel downloadable open source software stac! for mobile

devices that includes an operating sstem, middleware and !e applications based on

"inu# and $ava.

Google developed Android collaborativel as part of the Open Handset

Alliance, a group of more than %& mobile and technolog companies wor!ing to open

up the mobile handset environment. Android's development !it supports man of the

standard pac!ages used b $ett, and so, due to that fact and $ett's modularit and

lightweight footprint, it was possible to port $ett to it so that it will be able to run on

the Android platform.

This paper on Android deals with the histor of the Android, the earl

prototpes, basic building bloc!s of an android application and the features of the

android.


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CONTENTS

1. INTRODUCTION

2. FEATURES OF ANDROID

3. BUILDING BLOCKS

4. HARDWARE AND SOFTWARE RUNNING ANDROID

5. STORING, RETREIVING AND EXPOSING DATA

6. SECURITY AND PERISSIONS IN ANDROID

!. SYSTE ARCHITECTURE

". APPLICATIONS DEVELOPED ON ANDROID PLATFOR

#. ANDROID VERSIONS

1$. CONCLUSION

11. REFERENCES

INTRODUCTION


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Android is a software platform and operating sstem for mobile devices,

based on the "inu# !ernel, and developed b Google and later the Open Handset

Alliance. (t allows developers to write managed code in the $ava language, controlling

the device via Google-developed $ava libraries. Applications written in ) and other

languages can be compiled to A*+ native code and run, but this development path

isn't officiall supported b Google.

Android is available as open source. Google threw open the entire source

code including networ! and telephon stac!s that were not available previousl,

under an Apache license. )ertain parts that relate to a specific hardware can't be made

open and are not considered part of the Android platform. ith Apache "icense,

vendors are free to add proprietar e#tensions without submitting those bac! to the

open source communit. hile Google's contributions to this platform are e#pected to

remain open-sourced, the branches could e#plode using varieties of licenses.

FEATURES OF ANDROID

H%&'()* +%-*( Android can adapt to traditional smart phone laouts, as well

other /GA, 01, and %1 graphics libraries.


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S*-/%0)Android uses 23"ite to store all its un!-- ( mean, information.

C-&&)** Android supports a wide variet of technologies, including

5luetooth, i6i, G2+71G, and /-1O.

)((%0&0++2 and 2+2 are available for Android, as well as threaded te#t

messaging. 2o ou can send as man te#ties as ou li!e.

W) B/-()/ Android comes pre-loaded with the eb 9it application.

*emember, if ou don't li!e it, ou can alwas switch it out for something else

later on than!s to the open source nature of the Google Android bac!end.

%% V/*%+ %7&)2oftware ou write in $ava can be compiled in 1alvi!

5te codes sa that five times fast. ( !eep ending up with :1anish light bulb:.

These can then be put into a 1alvi! /irtual +achine. 5asicall more robust

applications are supported than on some other +obile Operating 2stems.

)'% S88-/*Android supports a wide range of audio, video, media, and still

formats. +;G-4, OGG, and AA) are ust a few of these.


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B/-%'%(* I&*)&* R)))/

S)/)

C-&*)&* P/-')/

A**

Activities are the most common of the four Android building bloc!s. An activit is

usuall a single screen in our application. ach activit is implemented as a single

class that e#tends the A** %() +%((. our class will displa a user interface

composed of /iews and respond to events. +ost applications consist of multiple

screens. 6or e#ample, a te#t 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. ach of these

screens would be implemented as an activit. +oving to another screen is

accomplished b a starting a new activit. (n some cases and activit ma return a

value to the previous activit -- for e#ample an activit that lets the user pic! a photo

would return the chosen photo to the caller.

I&*)&* %&' I&*)&* F+*)/(

Android uses a special class called (ntent to move from screen to screen. (ntent

describes what an application wants done. The two most important parts of the intent

data structure are the action and the data to act upon. Tpical values for action are

+A(? the front door of the application, /(, ;()9, 1(T, etc. The data is

e#pressed as a


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.

The new activit is informed of the intent, which causes it to be launched. The process

of resolving intents happens at run time when start Activit is called, which offers two

!e benefits@

Activities can reuse functionalit from other components simpl b ma!ing a reBuest

in the form of an (ntent

Activities can be replaced at an time b a new Activit with an eBuivalent (ntent

6ilter

B/-%'%(* R)))/

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