android system integration (sju 2010.04)

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© William W.-Y. Liang @ NTUT CSIE

Note: The Copyrights of the referenced slides go to its original author listed in each slide.

As a result, this slide is provided for internal reference only!

System Integration for

the Android Operating SystemWilliam W.-Y. Liang (梁文耀), Ph. D. Assistant Professor

Dept. Computer Science and Information EngineeringNational Taipei University of Technology



NTUT CSIE 嵌式平行系統實驗室


Android Handsets

2SJU 2004-04 Android

Motorola CliqHTC G1 HTC HeroSamsung i7500

Samsung Moment Motorola Droid HTC Magic HTC Tattoo

Sony X10





2010 Prediction


資料來源：DIGITIMES，2009/12

Near 9% Increment





A Prediction by Gartner


Android currently runs on less than 2% of all smartphones.

Predicted forecast for smartphone OS‟s by

2012: Symbian, 203 million devices sold (39% of the

market)

Android, 76 million devices sold (14.5% of the

market)

iPhone, 71.5 million devices sold (13.7% ofthe market)

Windows Mobile, 68.8 million devices sold

(12.8% of the market)

BlackBerry, 62.25 million devices sold (12.5%

of the market) Palm‟s WebOS, 11 million devices sold (2.1%

of the market)






About Android

Based on Slides in “Discussion on Android”, Mobile SIG, Larry Copeland ©

Android is a software platform and operating system mainly formobile devices based on the Linux operating systemdeveloped by Google and later the Open Handset Alliance.

It allows developers to write managed application code in Javalanguage that utilizes Google-developed Java libraries.

The unveiling of the Android platform on 5 November 2007 was

announced with the founding of the Open Handset Alliance(OHA), a consortium of 34 hardware, software, and telecomcompanies, such as Qualcomm, TI, Broadcom, Intel, Marvell,Nvidia, SiRF, WindRiver, T-Mobile, Sprint Nextel, China Mobile,KDDI, NTT DoCoMo, Motorola, Samsung, HTC, etc., devotedto advancing open standards for mobile devices.

Google has made most of the Android platform available underthe Apache free-software and open-source license, in Oct.2008 (to prevent the „GPL obstacle‟ problem in commercializingopen sources for industry companies.)


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The First Complete Android Phone

T-Mobile G1

Qualcomm® MSM7201A™, 528 MHz ROM: 256 MB, RAM: 192 MB Touch screen (320x480) Real Web browsing capabilities 3.2 MP camera

Customizable screen QWERTY keyboard Trackball 3G WCDMA, Quad-band GSM, Wi-Fi, Bluetooth 2.0

Software:

Easy access to Google applications

Maps (including satellite, traffic, and

street views), Gmail, YouTube,

Calendar, Google Talk

IM/text/e-mail

Music player, Video playback

One-click Google Search

Android Market




Google Nexus One


Source:http://blog.xuite.net/jon6773/blog/29930408

Estimated BOM Cost: US$174

http://blog.xuite.net/jon6773/blog/29930408







SJU 2004-04 Android

Android Architecture

99





The Linux Kernel

Based on Slides in “Smart Phone”, by Xiaohua Du and Xiaoyi Sheng ©

Android differs from the typical GNU/Linux in that

it adopts only the Linux kernel, not everything.

The first process „init‟ transfers to Android‟s own

application environment.

There is no shell by default, except using adb.

BSD libc is used instead of glibc or uClibc.

As a result, it is called Android/Linux, not

GNU/Linux.

Why Linux?

• Great memory and process management

• Permissions-based security model

• Proven driver model

• Support for shared libraries

• It‟s already open source!

Android relies on Linux version 2.6 for core systemservices such as security, memory management, processmanagement, network stack, and driver model.

Android relies on Linux version 2.6.25 and above for Android releases (1.0, 1.1, 1.5, and 2.0).

The kernel also acts as an abstraction layer between thehardware and the rest of the software stack.





Development Tools for Android Applications

Currently supported development platforms include x86-basedcomputers running Linux (any Linux Distribution), Mac OS X 10.4.8 orlater, Windows XP or Vista.

The Android SDK includes a comprehensive set of developmenttools, including a debugger, libraries, a handset emulator (QEMU),documentations, sample code, and tutorials.

http://developer.android.com/sdk/

Android Virtual Device (AVD)

Requirements also include Java Development Kit (JDK 5 or 6).

The officially supported integrated development environment (IDE) isEclipse (3.3 or 3.4) with the Android Development Tools (ADT) plugin.

http://www.eclipse.org/downloads/

Eclipse Android Plug-in: https://dl-ssl.google.com/android/eclipse/

Android Developer‟s Website

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





The IDE for Android





Android SDK

Based on slides from GreenLiff ©

ADT: Android Development Tool, an Eclipe plugin

Two debuggers

adb: Android Debug Bridge

ddms: Dalvik Debug Monitor Server

aapk : Android Application package tool

All resources are bundled into an archive, called apk file.

dx : java byte code to Dalvik executable translator

Android emulator : QEMU





Major Elements in Application Framework

Activity

Intent and Intent-Filter

Service

Content Provider

Broadcast Receiver

ActivitiesUI component typically

corresponding to one screen.

BroadcastReceivers Respond to broadcast Intents.

ServicesFaceless tasks that run in the

background.

ContentProvidersEnable applications to share

data.

Android Version API Level Release Time

2.1 7 2010.01

2.0.1 6 2009.12

2.0 5 2009.101.6 4 2009.09

1.5 3 2009.04

1.1 2 2009.02

1.0 1 2008.09




Activity (cont‟d)

Each activity is given a default window to draw in. Typically, the

window fills the screen, but it might be smaller than the screen andfloat on top of other windows.

The visual content of the window is provided by a hierarchy of views— objects derived from the base View class.

Android has a number of ready-made views that you can use — including buttons, text fields, scroll bars, menu items, check boxes,and more.

A view hierarchy is placed within an activity's window bythe Activi ty.setContentView () method. The content view is the Viewobject at the root of the hierarchy.





User Interface







Life Cycle of an Activity

Life cycle not directly controlledby application

System can kill an application tofree up memory.

Controll through onCreate(),onPause(), onStop() ... methods

Based on Slides from GreenLiff ©





An Example







Intents/Intent Filters

Slides from “Deep inside Android,” Gilles Printemps, Esmertec ©

Example:

Intent newActivity = new Intent (MyActivity.this, OtherActivity.class);

star tAct iv i ty( newActivity);

Provide a late runtime (asynchronous) binding between the code in

different applications (for activities, services, and broadcast receivers) Intents: Simple message objects that represent an intention to do

something

Intent Filters: A declaration of capacity and interest in offeringassistance to those in need

An “intent” is made up a number of pieces of information describing

the action or the service. (Specifically for activities and services) action -- The general action to be performed, such as

ACTION_VIEW, ACTION_EDIT, ACTION_MAIN, etc.

data -- The data to operate on, such as a person record in thecontacts database, expressed as a URI (Universe ResourceIdentifier).






Services

Similar to activities, but without UI

For long-running background tasks

Framework “Service” class must be extended

Slides from “Deep inside Android,” Gilles Printemps, Esmertec ©

Exampe:startService(new Intent(this_activity.this, some_service.class));

Core Services

Activity Manager

Package Manager

Window Manager

Resource Manager

Content Providers

View System

Hardware Services

Telephony Service

Location Service

Bluetooth Service

WiFi Service

USB Service

Sensor Service





24

Binder Example

SJU 2004-04 Android

Activity

Mp3PlayerWithService

Service

mp3Service

Binder

Mp3PlayerBinder

IBinder

A more complex IPC: AIDL - Android

Interface Definition Language





The Library Layer






Traditional Linux Model vs. Android Model


native C program

glibc & shared libs

Kernel

Hardware

System call

Hardware

System call

Kernel

JNI

bionic & shared libs

Android Framework

Application Service

getService ()

JNI Method





Shared Library


class HelloWorld {

public native void helloworld();

static {System.loadLibrary("hello");

}

public static void main(String[] args) {

new HelloWorld().helloworld();

}

}

JNI: Java Native InterfaceStandard interface between Java and C/C++

Libraries offer some form of sharing, allowing the samelibrary to be used by multiple programs at the same time.

Dynamic loading

Sharing

Examples

DLL (Dynamic Link Library): Windows

SO (Shared Object): Linux/Unix



Note: The Copyrights of the referenced slides go to its original author listed in each slide.

As a result, this slide is provided for internal reference only!

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