android

Savalia Devang 110570116054

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

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

• Android uses Linux for its device drivers,

memory management, process management, and networking.

• The next level up contains the Android native libraries. They are all written in C/C++ internally, but you’ll be calling them through Java interfaces. In this layer you can find the Surface Manager, 2D and 3D graphics, Media codecs, the SQL database (SQLite), and a native web browser engine (WebKit).

• Dalvik Virtual Machine. Dalvik runs dex files, which are converted at compile time from standard class and jar files.

Android Platform :Android Platform :

• Cellular networking : GSM, EDGE, 3G (hardware dependent)

• LAN : Bluetooth, and Wi-Fi (hardware dependent)

• Graphics Hardware Acceleration• Camera, GPS and Compass (hardware

dependent)• Touch screen and accelerometer for motion

sensing

Hardware which are supported :Hardware which are supported :

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• A business alliance consisting of 47 companies to develop open standards for mobile devices

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• Android provides a set of core applications: Email Client SMS Program Calendar Maps Browser Contacts Etc

• All applications are written using the Java language.

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• FeaturesFeature Role

View System

Used to build an application, including lists, grids, textboxes, buttons, and embedded web browser

Content Provider

Enabling applications to access data from other applications or to share their own data

Resource Manager

Providing access to non-code resources (localized strings, graphics, and layout files)

Notification Manager

Enabling all applications to display customer alerts in the status bar

Activity Manager

Managing the lifecycle of applications and providing a common navigation backstack

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• Including a set of C/C++ libraries used by components of the Android system

• Exposed to developers through the Android application framework

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• Dalvik Virtual Machine Providing environment on which every Android

application runsEach Android application runs in its own process, with its

own instance of the Dalvik VM.Dalvik has been written such that a device can run

multiple VMs efficiently.

Register-based virtual machine

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• Dalvik Virtual Machine (Cont) Executing the Dalvik Executable (.dex) format

.dex format is optimized for minimal memory footprint.Compilation

Relying on the Linux Kernel for:ThreadingLow-level memory management

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Relying on Linux Kernel 2.6 for core system services

Memory and Process Management

Network Stack

Driver Model

Security

Providing an abstraction layer between the H/W and the rest of the S/W stack

• Application Framework• Dalvik virtual machine• Integrated (webkit) browser• 2D and 3D graphics APIs with HW• SQLite• Video and audio codecs• Bluetooth, EDGE, 3G, and WiFi• Camera, GPS, compass, and accelerometer

• Java• Android SDK• Eclipse IDE(optional)• Android SDK has:

• Class Library• Developer Tools

dx – Dalvik Cross-Assembleraapt – Android Asset Packaging Tooladb – Android Debug Bridgeddms – Dalvik Debug Monitor Service

• Emulator and System Images • Documentation and Sample Code

Software Development Requires :Software Development Requires :

• CPU typically runs 500-600 Mhz• RAM available to an App may only be a few

megabytes• Disk (flash) access is very slow• Lifecycle - apps must pause/quit often, and restore to

give the illusion that they are always running• UI design

o typical screen may be HVGA (320x480)o may be in portrait or landscapeo very high DPI - small text may not be readableo touch resolution is very low (~25 pixel)

• Network access may be slow and (very) intermittent

• Ability to customize the Google Android platform

• Wide range of mobile applications to choose.

• Features like weather details, opening screen, live RSS feeds and many more.

• Entertainment functionalities will be taken a notch higher by Google Android being able to offer online real time multiplayer games.

 

Advantages :Advantages :

• We can only hope that the next versions of Android have overcome the actual limitations and that the future possibilities became a reality

Conclusion :Conclusion :