An Introduction to Android

AgendaWhy Mobile App Development?Different Operating SystemsAndroid Devices in the marketAndroid HistoryAndroid VersionsWhat is Android?Android PlatformOpen Handset AllianceOpen Handset MembersAndroid ArchitectureAndroid Development ProcessAndroid Build Process

Why Mobile App Development?Mobile platform is the platform of the future

Double-digit growth in world-wide smart phone ownership

Job market is hotMarket for mobile software rises day by day

Different Operating SystemsSymbian – Nokia – Microsoft

BlackBerry – Research In Motion (RIM)

iOS (known as iPhone OS) – Apple

WebOS – Hewlett Packard (HP)

Bada – Samsung

Windows Mobile - Microsoft

Android Devices in the market

Smart PhonesTabletsE-Reader DevicesNetBooksMP4 PlayersInternet TVs

Android History

Android Inc.founded in Palo Alto,california ,united states in October 2003 by Andy Rubin.

It was developed by Google and later the Open Handset Alliance (OHA).

Android Versions

Version Code name Release date API level

Android 1.0 Apple pie 2008 1

Android 1.1 Banana bread February 9, 2009 2

Android 1.5 Cupcake April 30, 2009 3

Android 1.6 Donut Sept 15, 2009 4

Android 2.0/2.1 Eclair Oct 26, 2009 7

Android 2.2 Froyo May 20, 2010 8

Android 2.3.3–2.3.7 Gingerbread February 9, 2011 10

Android 3.0-3.2.6 Honeycomb February 22, 2011 13

Android 4.0.3–4.0.4 Ice Cream Sandwich December 16, 2011 15

Android 4.1.x Jelly Bean July 9, 2012 16

Android 4.2.x Jelly Bean November 13, 2012 17

Android 4.3 Jelly Bean July 24, 2013 18

Android 4.4 KitKat October 31, 2013 19

Android 5.0 Lollipop October 17, 2014 20

What is Android? It is a open source software platform and operating system

for mobile devices

Android is a software environment built for mobile devices

It is based on the Linux kernel

Developed by Google and later Open Handset Alliance (OHA)

Android application are built in Java language

Android has its own virtual machine called DVM(Dalvik Virtual Machine),which is used for executing the android application

Android platform isComplete:

The android application development began with secure operating system and robust framework for rich application development

Open: The platform is provided through open source licensing,

also we have access to handset features while developing applications

Free: Android applications are free to develop, as Andriod SDK,

ADT, etc required plugins are free

What is Open Handset Alliance? Open Handset Alliance is a consortium of

47 hardware, software, and telecom companies devoted to advancing open standards for mobile devices.

i.e. to deliver the consumer a richer, less expensive and better mobile experience.

OHA’s aim is to Develop technologies that will significantly lower the cost of developing and distributing mobile devices and services.

Open Handset Members Operators

T-Mobile, Telecom Italia, Telefonica, NTT DoCoMo, KDDI, Sprint, China Mobile

Handset Manufacturers HTC, LG, Motorola, Samsung

Semiconductor Companies Audience, Broadcom, Intel, Marvell, NVIDIA, Qualcomm, SiRF,

Synaptics, Texas Instruments Software Companies(Applications)

Ascender, eBay, Esmertec, Google, LivingImage, NMS communications, Packet Video, SkyPop

Commercialization Companies Aplix, TAT, Wind River, Noser

Android ArchitectureBefore starting with Android ArchitectureWhy we are using Linux?

Because Linux kernel is proven core platformIt is reliableIt provides securityHardware driversProcess managementMemory managementPower management

Android ArchitectureFour main Layers of Android architecture are

1. Applications2. Application Framework3. Libraries and Android Runtime4. Linux Kernel

• Linux 2.6 Kernel• Hardware Abstraction Layer (HAL) between

hardware and android software stack• Provides memory management/ Process

management/ Power management• It provides security• Different Driver software's to manage Display,

Camera, Wi-Fi, etc…• IPC – Inter Process Communication

• Android Libraries are develped in C/C++• We cannot access these libraries directly, to access these

libraries we need application framework

Surface Manager – used for display management

Open GL/ES(Open Graphics Library/Extended system)

and SGL(Scalable Graphics Library) – used for 2D/3D Graphics mainly for game development

Media Framework – (PacketVideo)Audio/Video codes(mp3, mpg4)

FreeType – Font rendering

SSL(Secured Socket Layer) – to have secure internet connection

SQLite – Datastore i.e. Database

WebKit – Browser Engine to display webpages

libc – System C libraries

Core Libraries – It is written in Java language. It contains all of the collection classes, utilities, IO.

Dalvik Virtual Machine(DVM)• Register based Virtual Machine• Optimized for Low memory requirements, limited

battery and limited CPU• Designed to allow multiple VM instances to run at once• Every program runs in its own VM instance• Operates on DEX files• Android byte codes are interpreted at runtime by DVM

• This is written in Java language and using Application Framework we develop our Android applications.

Activity Manager – launcher, building block of application, whatever is displayed on the screen

Window manager – It is use to create views and layouts.Content Providers – used to share data of one application

to another. e.g. contacts, call log detailsNotification manger – whenever you get emails, sms,

missed call we get notification i.e. alertsView System – Button, textbox, checkbox, etc whatever

we see is nothing but View system

Resource Manager – We use View, images, audio/video files, xml files, layout files all these additional things we are using are handled by Resource Manger

Location Manger – It helps user to trace through geographical location

Package Manager – It is use to retrieve the data about installed packages on device. Telephony manager – It is use to handle settings of

network connection and all information about services on device.

• Top most layer of android architecture• By default some applications are already available

like calculator, some browser, contacts that is what application layer

Development process of an Android appAndroid apps are built using Java and Android SDK

librariesThe Java code is compiled into Dalvik byte code i.e. .dexThe Dalvik Virtual Machine runs the .dex files

Development process of an Android app

Development process of an Android app

Android application Build ProcessAndroid application are built in Java so first of all we

have Application Source Code that is our own Java programs

If written in other language then using aidl(android interface definition language) tools, will generate Java interfaces

We have images, audio/video files, xml files all these resources in our android application, which are converted into the file called R.java

Who created this R.java then it is aapt (android asset packing tool)

All these Java programs are given to Java compilerJava compiler will create .class files

Android application Build Process

Android application Build ProcessThese .class files are given to dex(delvik executable tool)

toolsSome other additional class files like Google map class

files are i.e. 3rd Party Libraries and Class Files are also given to Dex tool

Now this Dex tool will create a single dex file.This dex file along with the compiled resources from AAPT

and other additional resources is given to APK BuilderThis APK Builder creates our android application i.e. .apk

file

Android application Build Process

Android application Build ProcessNow to deploy it we need to follow two more steps

http://developer.android.com/tools/building/index.html

Referenceshttp://developer.android.com/index.htmlhttp://www.android.com

Thank you

- Rajesh Jambukia