Android

[Premdas]

Android
What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.
Features
Application framework enabling reuse and replacement of components
Dalvik virtual machine optimized for mobile devices
Integrated browser based on the open source WebKit engine
Optimized graphics powered by a custom 2D graphics library; 3D graphics based on the OpenGL ES 1.0 specification (hardware acceleration optional)
SQLite for structured data storage
Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
GSM Telephony (hardware dependent)
Bluetooth, EDGE, 3G, and WiFi (hardware dependent)
Camera, GPS, compass, and accelerometer (hardware dependent)
Rich development environment including a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE
Android Architecture
The following diagram shows the major components of the Android operating system. Each section is described in more detail below.
Applications
Android will ship with a set of core applications including an email client, SMS program, calendar, maps, browser, contacts, and others. All applications are written using the Java programming language.
Application Framework
By providing an open development platform, Android offers developers the ability to build extremely rich and innovative applications. Developers are free to take advantage of the device hardware, access location information, run background services, set alarms, add notifications to the status bar, and much, much more.
Developers have full access to the same framework APIs used by the core applications. The application architecture is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by the framework). This same mechanism allows components to be replaced by the user.
Underlying all applications is a set of services and systems, including:
A rich and extensible set of Views that can be used to build an application, including lists, grids, text boxes, buttons, and even an embeddable web browser
Content Providers that enable applications to access data from other applications (such as Contacts), or to share their own data
A Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
A Notification Manager that enables all applications to display custom alerts in the status bar
An Activity Manager that manages the lifecycle of applications and provides a common navigation backstack
For more details and a walkthrough of an application, see the Notepad Tutorial.
Libraries
Android includes a set of C/C++ libraries used by various components of the Android system. These capabilities are exposed to developers through the Android application framework. Some of the core libraries are listed below:
System C library - a BSD-derived implementation of the standard C system library (libc), tuned for embedded Linux-based devices
Media Libraries - based on PacketVideo'sOpenCORE; the libraries support playback and recording of many popular audio and video formats, as well as static image files, including MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG
Surface Manager - manages access to the display subsystem and seamlessly composites 2D and 3D graphic layers from multiple applications
LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view
SGL - the underlying 2D graphics engine
3D libraries - an implementation based on OpenGL ES 1.0 APIs; the libraries use either hardware 3D acceleration (where available) or the included, highly optimized 3D software rasterizer
FreeType - bitmap and vector font rendering
SQLite - a powerful and lightweight relational database engine available to all applications
Android Runtime
Android includes a set of core libraries that provides most of the functionality available in the core libraries of the Java programming language.
Every Android application runs in its own process, with its own instance of the Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently. The Dalvik VM executes files in the Dalvik Executable (.dex) format which is optimized for minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler that have been transformed into the .dex format by the included "dx" tool.
The Dalvik VM relies on the Linux kernel for underlying functionality such as threading and low-level memory management.

[varalakshmi]

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INTRODUCTION

Android is a software stack for mobile devices that includes an operating system, middleware and key applications.

Android is a software platform and operating system for mobile devices based on the Linux operating system and developed by Google and the Open Handset Alliance.

Google Acquires Android Inc:
In July 2005, Google acquired Android Inc,
which was a small startup company based
in Palo Alto.

Open Handset Alliance Founded:
On 5 November 2007, the Open Handset Alliance was formed.
Google, HTC, Intel, Motorola, Qualcomm, T-Mobile, Sprint Nextel and NVIDIA and many more were members and Android was released to market as an Open Source OS.

What makes Android special?
A truly open, free development platform
based on Linux and open source.

A component-based architecture inspired by Internet mash-ups. Parts of one application can be used in another.

Automatic management of the application life cycle. Programs are isolated from each other by multiple layers of security, provide system stability.

High quality graphics and sound. Uses OpenGL for graphics and supports MP3, MP4 etc for audio and videos.

Linux Kernel:
Android Architecture is based on Linux 2.6
kernel. Manage security, memory management, process management, network stack.

CDMA and GPRS network support
Bluetooth 1.2 and Wi-Fi support
Digital audio support for mp3 and other formats
Support for Linux and other third-party operating systems
Java hardware acceleration and support for Java applications
Qcamera up to 6.0 megapixels
gpsOne solution for GPS
and lots of other.

Libraries :
Native libraries written in C/C++,
which are responsible for stable performance.

Media Libraries - based on PacketVideo's OpenCORE; the libraries support playback and recording of many popular audio and video formatslike MPEG4, MP3, JPG, and PNG.

Surface Manager Responsible for displaying 2D and 3D graphic layers from multiple applications .

LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view.

3D libraries - an implementation based on OpenGL ES 1.0 APIs; the libraries use hardware 3D acceleration.

SQLite - a powerful and lightweight relational database engine available to all applications

Android Runtime:
Dalvik Virtual Machine.
Android gives an integrated tool dx , which
converts byte code from .jar to .dex file which is
much more efficient.

Designed for Android running with limited battery, CPU, memory and data storage.

As the result, it is possible to have multiple instances of Dalvik virtual machine running on the single device at the same time.

Application Framework:
Written in Java language. It is a toolkit that all
applications uses and are developed.

The Activity Manager manages the life circle of the applications and provides a common navigation back stack for applications

The Package Manager keeps track of the applications, which are installed in the device.

Telephony Manager contains of a set of API necessary for calling applications.

Content Providers was built for Android to share a data with other applications

The View System generates a set of buttons and lists used in UI.

Application Layer:
Here we have all the applications, which are used by the final user.

Application Building Blocks:
Android application is a collection of
components, of various kinds.

The major building blocks of an application are:
- Activity: User interface component, which
corresponds to one screen at time.
- Intent Receiver: Wakes up a predefined action
through the external event.
- Service: A task, which is done in the background.
- Content Provider: A component, which allows sharing
some of the data with other processes and
applications.

Advantages of Android:
Open - Android allows access to core
mobile functionality through standard
API calls.

All applications are equal - Android does not differentiate between the phone's basic and third-party applications.

Fast and easy development - The SDK contains everything needed to build and run Android applications, including a true device emulator and advanced debugging tools.

Disadvantages of Android:
Security - Making source code available
to everyone in unsafe.

Incompetence - Google s dependence on hardware and carrier partners puts the final product out of their control.

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[nitiraj18]

ANDROID.
What is ANDROID
Google's Android is an open-source platform that's currently available on a wide variety of smart phones.
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.
The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.
Based on the Linux kernel
Open Handset Alliace
Est. 5th Nov 2007, led by Google, open Source
Main Product Android Platform
Enthusiastic Support from Industry
Equipment makers
Network Operators
HTC was First to deliver ANDROID
ANDROID ARCHITECTURE
The software stack is split into Four Layers::
The application layer
The application framework
The libraries and runtime
The kernel
Applications
Set of core applications including an email client, SMS program, calendar, maps, browser, contacts
All applications are written using the Java programming language.
Application Framework
Access location information, run background services, set alarms, add notifications to the status bar, and much, much more.
Build an application, including lists, grids, text boxes, buttons, and even an embeddable web browser
Providing access to non-code resources such as localized strings, graphics, and layout files
Libraries
System C library - implementation of the C library (libc)
Media Libraries - based on PacketVideo's OpenCORE
Surface Manager - composites 2D and 3D graphic layers
LibWebCore - a modern embeddable web view
SGL - the underlying 2D graphics engine
3D libraries - based on OpenGL ES 1.0 APIs; the libraries use hardware 3D acceleration
FreeType - bitmap and vector font rendering
SQLite - a powerful and lightweight relational database engine
Android Runtime
Includes a set of core libraries of JAVA that provides most of the functionality
Runs in its own process, with its own instance of the Dalvik Virtual Machine
The Dalvik VM executes files in the Dalvik Executable (.dex)
Linux Kernel
Acts as an abstraction layer between the hardware and the rest of the software stack.
Relies on Linux version 2.6 for core system services such as security, memory management, process management, network stack, and driver model.
Anatomy of Android Application
There are four building blocks for an Android application:
Activity
a single screen
Intent Receiver
to execute in reaction to an external event(Phone Ring)
Service
code that is long-lived and runs without a UI(Media Player)
Content Provider
an application's data to be shared with other applications
WHY ANDROID??
AnyCut
TasKiller Free
ASTRO File Manager
Slide Screen
Google s Android OS for future MIDs
Google to utilize its Android-based operating system on future Moorestown
Android is available on a variety of handsets, including Google's Nexus One and Verizon's Motorola Droid
Two Android-centric phones T-Mobile s G1 and phone called Magic made by HTC
Google, the developer of Android, says there are eight or nine mobile phone manufacturers that are planning to release 18 to 20 Android-based models by the end of the year.
Cellphones Using Android OS
Market Research
The Android OS has knocked Apple out of the number 2 slot and slid just behind RIM.
NPD says first quarter sales ::Android has 28% while Apple has 21%.
Not only are Android-powered devices now outselling iPhone but they re also now besting BlackBerry, making Android the top selling mobile OS during the second quarter in the U.S.
NPD has the race at Android 33%, RIM 28%, and Apple 22% for the period
Conclusion
Android is open to all: industry, developers and users
Participating in many of the successful open
source projects
Aims to be as easy to build for as the web.
Google Android is stepping into the next level
of Mobile Internet