android michaelmorckos may 13 09

8/3/2019 Android Michaelmorckos May 13 09

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IntroductionAndroid Architecture

Android Application FundamentalsAndroid SDK

Summary

Android Architecture

Michael Y. Morckos

German Univeristy in Cairo

May 13, 2009

Michael Y. Morckos Android Architecture
http://find/http://goback/


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Summary

What is Android

What is Android

Android is an operating system for mobile devices Its an integrated open source software stack for mobile device

Operating system Middleware Key mobile applications

Went open source in late 2008. Released under the Apache v2license



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Summary

What is Android

History

Google acquired Android Inc. in July 2005



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Summary

What is Android

History


The Android team, led by Andy Rubin, developed a mobiledevice platform powered by Linux operating system



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Summary

What is Android

History


The Android team, led by Andy Rubin, developed a mobiledevice platform powered by Linux operating system

This signaled Googles entry into the mobile-phone market



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Summary

What is Android

Open Handset Alliance

A consortium established by Google in November 2007



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Summary

What is Android



34 members including key companies in mobile handsets,application developments and mobile chips industries.



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Summary

What is Android




The consortium aim at providing open standards for mobiledevices for richer capabilities and reduced cost



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Summary

What is Android





On the same month Android was unveilled, marking it theflagship product of the OHA consortium



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Summary

What is Android





On the same month Android was unveilled, marking it theflagship product of the OHA consortium

The T-Mobile G1 (HTC Dream) was the first mobile devicepowered by Android. Released on October 2008



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Summary

What is Android

Innovative Features

Linux kernel

Open system Component based

Java programming language for applications development

Enable mobile applications to exploit full advantage of all a

handset has to offer No boundaries

Fast & easy development


Contents


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Summary

OverviewLinux KernelAndroid RuntimeNative LibrariesApplication FrameworkApplications

Contents

Overview Linux Kernel

Android Runtime

Android Native Libraries

Application Framework Applications


Contents


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Summary


Android Stack


Contents


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Summary


Android Architecture


I d iContentsO i


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Summary


Kernel


I t d tiContentsO i


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Summary


Overview

Android uses a heavily modified GNU/Linux kernel version 2.6for handling core system infrastructure services as security,memory management, process management, network stack,and driver model

The kernel provides an abstraction layer between the hardware

and the rest of the software stack Include many enhancements and modifications


IntroductionContentsOverview


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Summary


Android Power Management

A light-weight power managemenr driver built atop thestandard linux power management Constrainted power management policy

CPU shouldnt consume power if no applications or servicesrequire power

Components make requests to keep the power on throughWake Locks




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Summary


Binder

An OpenBinder-based driver to facilitate inter-processcommunication (IPC) on the Android platform

OpenBinder provides: High performance through shared memory Per-process thread pool for processing requests Synchronous calls between processes




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Summary


Memory Management

Low Memory Killer: based on feedbacks from user

applications, the low memory killer can kill processes to freeup memory as necessary

Provides more flexibility than the Out Of Memory (OOM)killer in the standard kernel

Android PMEM: the PMEM (physical memory) driver is usedto provide contiguous physical memory regions to userspacelibraries that interact with the processor and other hardware




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Summary


Other Components

Logger: A light weight logging device used to capture system,radio, logdata, etc.

Android Alarm: A driver which provides timers that can wakethe device up from sleep and a monotonic timebase that runswhile the device is asleep

M-Systems: for memory cards and other flash media storage

Other conventional drivers: Bluetooth Display Keypad Audio ...




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Android ArchitectureAndroid Application Fundamentals

Android SDKSummary

Linux KernelAndroid RuntimeNative LibrariesApplication FrameworkApplications

Runtime




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Android SDKSummary


Overview

A vital component in the Android stack




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Android SDKSummary


Overview

A vital component in the Android stack Composed of two major parts:

The Dalvik virtual machine Core libraries




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Android SDKSummary


Dalvik Virual Machine

One of the most important components in Android


IntroductionA d id A hi

ContentsOverviewLi K l


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Android SDKSummary




Developed by Dan Bornstein, and named after the Dalvikvillage in Iceland


IntroductionA d id A hit t

ContentsOverviewLi K l


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Android SDKSummary




Developed by Dan Bornstein, and named after the Dalvikvillage in Iceland

Three main design targets: runs on a limited CPU and RAM (250-500MHz) (20-40 MB)

runs atop an OS with no swap space runs on a device with limited power



ContentsOverviewLinux Kernel


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Android SDKSummary


From .class to .dex

Dalvik replaces the JVM in providing the runtime environmentto Java platform applications





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Android SDKSummary


From .class to .dex


The VM runs Java applications which have been converted tothe Dalvik Executable format .dex





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Android SDKSummary


From .class to .dex



The dx tool available in the SDK converts Java bytcode toDVM bytcode at build time





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Android SDKSummary


From .class to .dex




The dx format is a highly efficient and compact bytecode





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Summary

Android RuntimeNative LibrariesApplication FrameworkApplications

From .class to .dex




The dx format is a highly efficient and compact bytecode dx files can be installed on different devices and can be

further modified after being installed to increase efficiency





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Summary


Dalvik Features

Highly CPU optimized interpreter No just-in-time compiling

Shared constants pool and data structures

Static linking

Bytes reordering





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Summary


Core Libraries

Androids core libraries provide most of the functionalityavailable in the core libraries of Java needed for applicationsdevelopment: I/O functionalities Collections File access ...



A d id A li i F d l

ContentsOverviewLinux KernelA d id R i


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Summary


Native Libraries



A d id A li ti F d t l

ContentsOverviewLinux KernelA d id R ti


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Summary


Overview

This layer houses the core libraries providing the bulk ofAndroid functionalities

Implemented in C/C++

Developers can exploit the full capabilities of these libs

through the application framework layer



Android Application Fundamentals

ContentsOverviewLinux KernelAndroid Runtime


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Summary


Bionic (libC)

A BSD-based implementation of the standard C library, tuned

for embedded Linux-based devices 200 KB in size, roughly half the size of the standard GNU C

library libc

Bionic includes a very fast and small custom POSIX-thread

implementation Compatability issue with GNU libc






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Summary


SQLite

A powerful lightweight embedded relational databasemanagement system contained in a relatively small ( 500 kb)

C library The engine is not a standalone entity. Instead, a SQLite

database is just another program linked in and thus becomesan integral part of the program

The database is stored as a single cross-platform file on thehost machine

Application access SQLite through conventional simplefunction calls






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Summary


Surface Manager

Responsible for composing different drawing surfaces on the

mobile screen Manages access for different processes to the underlying

display subsystem and composites 2D and 3D graphic layersfrom multiple applications

Layers passed as buffers via Binder IPC calls

Use OpenGL/ES and 2D hardware accelerator for itscompositions






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Summary


OpenGL/ES & SGL

Subset of the OpenGL 3D graphics API designed for

embedded devices Defined and promoted by the Khronos Group, a graphics

hardware and software industry consortium

Can use either hardware 3D acceleration (hardwaredependent) or the included highly optimized 3D softwarerasterize

SGL is Androids specialized 2D graphics library






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ndroid pplication FundamentalsAndroid SDK

Summary

ndroid RuntimeNative LibrariesApplication FrameworkApplications

Media Framework

Provided by PacketVideos multimedia package OpenCore

The OpenCore provides a universal structure for mobilemultimedia applications

Support for standard video, audio, still-frame formats(MPEG4, MP3, AAC, AMR, JPG, and PNG, H.264)

Support for codec plug-ins






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ppAndroid SDK

SummaryNative LibrariesApplication FrameworkApplications

FreeType

Implements a font rasterization engine

Written in C

It is used to rasterize characters into bitmaps and providessupport for other font-related operations






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Android SDKSummary

Native LibrariesApplication FrameworkApplications

LibWebCore (WebKit)

A framework providing the basis for building a web browserbased on the open source WebKit browser

Written in C++

Rendering of pages in full (desktop) view

Support for modern web technologies; CSS, JavaScript, DOM,AJAX






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Android SDKSummary


Audio Manager (Audio Flinger)

Processing multiple audio streams into PCM audio out paths



Android Application FundamentalsA d id SDK

ContentsOverviewLinux KernelAndroid RuntimeN i Lib i


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Android SDKSummary


Framework Overview



Android Application FundamentalsA d id SDK

ContentsOverviewLinux KernelAndroid RuntimeN ti Lib i


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Android SDKSummary


Overview

A general purpose toolkit that all applications use

Written in Java

Enable reuse and replacement of components




ContentsOverviewLinux KernelAndroid RuntimeNative Libraries


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Android SDKSummary


View System

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






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Android SDKSummary


Resource Manager

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






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Android SDKSummary


Notification Manager

Enabling all applications to display customer alerts in thestatus bar






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Android SDKSummary


Activity Manager

Managing the lifecycle of applications and providing acommon navigation backstack






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Summary Application FrameworkApplications

Telephony Manager

Provides core telephoning functionalities






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XMPP Service

An Open, XML-based protocol originally aimed atnear-real-time, extensible instant messaging

Largely extended. VoIP Aims to:

Send simple P2P message between handsets Send and receive IMs using Googles Talk






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Location Manager

Allows applications to obtain periodic updates devices geographical location triggers an application-specified event when the device enters

the proximity of a given geographical location






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Window Manager

The window manager creates display surfaces for theapplication

Responsible for organizing the screen and display of differentlayers of application




S

ContentsOverviewLinux KernelAndroid RuntimeNative LibrariesA li i F k


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Applications

Android comes with a bundle of core applications:

email client

SMS program

calendar

maps

browser

contacts

...




S

IntroductionApplication ComponentsComponents Activation/DeactivationTasksC t Lif l


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Summary Components Lifecycle

Overview

Written in Java (as you know)




Summary

IntroductionApplication ComponentsComponents Activation/DeactivationTasksComponents Lifecycle


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Overview

Written in Java (as you know) The compiled application is bundled by the aapt tool into an

Android package .apk




Summary



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Overview

Written in Java (as you know) The compiled application is bundled by the aapt tool into an

Android package .apk

Like .jad & .jar in J2ME, .apk files are distributed andinstalled on Android powered devices




Summary



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Basic Facts

Every application: is a single Linux process

has its own VM instance

is assigned a unique Linux user ID




Summary



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Basic Facts

A key feature of Android is that applications can publishtheir functionalities

An application can use other functionalities provided by otherapplications

Android applications dont have a single entry point




Summary



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y p y

Application Diagram




Summary



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y p y

Activities Class in the API An activity presents the user with a visual UI for a specific

functionality

Application can have several activities Each activity is given a default window to draw in The visual content of the window is provided by a hierarchy of

views User interacts with activities through the views Android provides several built-in views:

Buttons Menus Text fields ...




Summary



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Services

Background functionalities

Run in the applicationss thread




Summary



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Content Provider

Provides applications with required applications data Data stored in a SQLite DB

Applications talk to content provider through a contentresolver




Summary



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Broadcast Receiver

Receive and react to broadcast announcements

Many originate from system level

Persistent




Summary



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Activation

Content providers are activated when targeted by applications

(implicit activation) Broadcast receivers are activated when receiving

Services and activities are activated by intent msgs

Intent messages contains ID of component to be activated +

URI of data to be used Intent filters




Summary



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Deactivation

Content providers and broadcast receivers are shut down oncethey are done

Activities and services require explicit shutdown

Components might also be shut down by the system toreclaim memory for higher priority components (life cycle)




Summary



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Tasks

Different activities can be activated on demand

A group of activities composes a task. They are maintained ina stack

Users experience of an application can actually be a taskconsisting of different activities from different applications

Can have a stack of tasks as well




Summary



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Activity

Activities can be in one of these states at an instance:

Active: has the users focus, displayed in the foreground

Paused: still visible but under another active activity

Stopped: completely obscured by another activity, no longervisible

If an activity is paused or stopped, the system can drop it from

memory. When the user returns to it, the system must restore it toits previous state




Summary



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Activity

Entire lifetime: from the moment the activity is created tilldestroyed

Visible lifetime: from the moment the activity activated tillstopped

Foreground lifetime: between resuming and pausing an activity




Summary



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Activity Lifecycle




Summary



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Service

Services can be shutdown explicity or implicitly

Entire lifetime: from creation till destruction

Active lifetime: from activation




Summary



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Broadcast Receiver

Broadcast receiver is active when receiving and reacting to anotification

A process with an active broadcast receiver is protected frombeing killed

Active lifetime: from activation




Summary


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Overview

The SDK includes a full set of tools for developing anddebugging application

Designing UIs Major components in version 1.5:

Android Development Tools Plugin (for the Eclipse IDE) Android Emulator Android Virtual Devices (AVDs); specifiying different platform,

hardware options, skins... Dalvik Debug Monitor Service (ddms) Android Asset Packaging Tool (aapt) sqlite3 dx tool




Summary


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Standard Procedure: Hello, World




Summary


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Summary

Whats Android Android Architecture


Android SDK




Summary


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Android Closing...

Questions? Thank you for your attention!


IntroductionAndroid ArchitectureAndroid Application Fundamentals

Android SDKSummary


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References

http://developer.android.com/

http://androidlinux.com/

http://www.dalvikvm.com/

http://www.bindaaspoll.com/googleandroid/index.htm

http://benno.id.au/blog/2007/11/26/what-is-android

http://it.toolbox.com/wiki/index.php/Dalvik virtual machine

http://blog.codebeach.com/2007/11/android-architecture-overview.html

http://stuffthathappens.com/blog/2009/04/12/google-io-2008-dalvik-virtual-machine-internals/


IntroductionAndroid ArchitectureAndroid Application Fundamentals

Android SDKSummary


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References

http://www.kandroid.org/android pdk/intro source code.html

http://sites.google.com/site/io/dalvik-vm-internals

http://www.brighthub.com/mobile/google-

android/articles/17822.aspx http://gfilab.wordpress.com/2008/05/21/android-a-quick-

overview/

http://moss.csc.ncsu.edu/ mueller/g1/slides/platform.ppt

http://www.softdevtube.com/2008/09/16/inside-the-android-application-framework/

http://groups.google.com/group/android-framework/browse thread/thread/34a635dd68c8b4f4


android michaelmorckos may 13 09

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