MELJUN CORTES ANDROID Lecture Architecture

8/20/2019 MELJUN CORTES ANDROID Lecture Architecture

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Programming with Android:System Architecture

MELJUN P. CORTES,MBA,MPA,MSCS in pro


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MELJUN P. CORTES- Programming with Android – System Architecture

Outline

Android Components: Content Providers

Android Components: Services

Android Components: Intents

Android Components: Activities

Android Dalvik Java Virtual Machine

Android Architecture: An Overview

Android Application Distribution and Markets


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Android … What?

Android is a Linux-based platform fo

devices …

Operating System

Middleware

Applications

Software Development Kit (SDK)

Which kind of mobile devices … (exa

SMARTPHONES TABLETS EREADERS ANDROID TV GOOGLE GLASSES


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Android … What?

SMARTPHONES TABLETS EREADERS ANDROID TV GOOGLE GLASSES

SMART FRIDGE

ANDROID MICROW


5/42MELJUN P. CORTES- Programming with Android – System Architecture

Android … When?

Google buys Android from the Android In

Open Handset Alliance (OHA) created for

standards for mobile devices. Partners of OHGoogle, Motorola, Samsung, Vodafone, T-Mobile

Android 1.0 Released

The first Android smartphone: G1 HTC-Drea

Android 1.1 Released

Android 1.5 (CupCake) Released

2005

2006

2007

2008

2009

Time



Android … When?

Android 1.6 (Donut) Released

Android 2.0 (Eclair ) Released

Android 2.2 (Froyo) Released

Android 2.3 (Gingerbread) Released

Android 3.0 (Honeycomb) Released(First version for devices with larger screens such as tablets

Android 4.0 (Ice-Cream Sandwich) Relemerges the 3.x tab centric design and the v2.x phone bas

into a single version.)

2008

2009

2010

2011

2012

Time



Android … When?

Android 4.4 (Kitkat) Released

Wireless printing capability

Ability for applications to use "immersive mod

Performance optimization

New experimental runtime virtual machine, A

API Level 19 (Android 4.4):

Support to new embedded sensors (e.g. STEP_DETECTOR)

Adaptive video playback functionalities

Read and write SMS and MMS messages

(managing default text messaging client)

2012

2013

Time

ANDROID 5.0

2014



Android … When?

2012 Market Share 2013 Market Sharewww.gartner.com


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Android … When?

h t t p : / / o p e n s i g n a l . c o m / r e p o r t s / f r a g m e n t a t i o n - 2 0 1 3 /

11,868 different devices in 2013!


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Android … When?

http://developer.android.com/about/dashboards/index.

Updated at February 2014


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Android … When?

ANDROID VER

HISTORY AND PO

(2009-201

http://en.wikipedia.org/wiki/Android_version_history

4.x

2.3.x

2.2.x

1.6-2.0


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Android … When?

http://www.appbrain.com/stats/android-market-app-categories

ANDROID APP CATEGORIES

http://www.onlinemarketing-trends.com/2011

marketplace-top-5-statistics.html

ANDROID APP PRICE


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The Android Architecture

} S ArchOpen Source

(Apache/MIT L

Business-frien


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Built on topkernel (v. 2

Advantages:

Portabilitycompile on di

hardware arc

Security (e.multi-process

Power Man


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Native Libr

(C/C++ code)

Graphics (Su

Multimedia (

Database DB

Font Manag(FreeType)

WebKit

C libraries (B

….


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Application(Core Components

Activity Man

Packet Mana

Telephony M

Location Ma

Contents Pr

Notification

….


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Applicatio(Written in Java co

Android Pla

Entertainme

Productivity

Personalizat

Education

Geo-commu

….


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Dalvik Virt

Machine (V

Novel Java V

Machine imple

(not using the O

Open Licens

JVM is not ope

Optimized fo

constrained de

Faster than O

….

l ik i l hi ( )


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Dalvik Java Virtual Machine (JVM)

Java Source

Code

Java Byte

Code

Java Virtual

Machine (JVM)

Java Source

Code

Java Byte

Code

Dalvik Byte

Code

Dalvik Virtual

Machine (VM)

Java

Compiler

Java

Compiler

Dex

Compiler Stack-based

byte-code

Register-

byte-code

Java Standard Edition

A d id A li i D i


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Android Applications Design

GUI Definition

Events Management

Application Data Manageme

Background Operations

User Notifications

APPLICATION DESIGN:

A d id A li ti D i


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Android Applications Design

Activities & Fragments

Intents

Services

Content Providers

Broadcast Receivers

APPLICATION COMPONENTS

A d id C t A ti iti


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An Activity corresponds to a single

of the Application.

An Application can be composed of

screens (Activities).

The Home Activity is shown when tlaunches an application.

Different activities can exhange info

one with each other.

Hello World!

Android HelloWorld

Button1

A d id C t A ti iti


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Each activity is composed by a list of graphics compo

Some of these components (also called Views) can inwith the user by handling events (e.g. Buttons).

Two ways to build the graphic interface:

Example:

Button button=new Button (this);TextView text= new TextView();text.setText(“Hello world”);

PROGRAMMATIC APPROACH



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Each activity is composed by a list of graphics comp

Some of these components (also called Views) canwith the user by handling events (e.g. Buttons).

Two ways to build the graphic interface:

Example:

< extView android.text=@string/hello” android:textcolor=@color/bluandroid:layout_width=“fill_parent” android:layout_height=“wrap_cont< utton android.id=“@+id/Button01” android:textcolor=“@color/blueandroid:layout_width=“fill_parent” android:layout_height=“wrap_cont

DECLARATIVE APPROACH



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- Build the application layou

through XML files (like HTML

- Define two different XML la

for two different devices

- At runtime, Android detects

current device configuration

loads the appropriate resoufor the application

- No need to recompile!

- Just add a new XML file if y

need to support a new devi

EXAMPLE

Device 1HIGH screen pixel density

Device 2LOW screen pixel density

XML Layout FileDevice 1 XML Layout FileDevice 2

Java App Code




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EXAMPLE

Device 1HIGH screen pixel density

Device 2LOW screen pixel density

XML Layout FileDevice 1 XML Layout FileDevice 2

Java App Code


http://developer.android.com/about/dashboards/index

SCREEN CONFIGURATION DISTRIBUTION



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Android applications typically use both the approach

DECLARATIVE APPROACH

PROGRAMMATIC APPROACH

Define the Application layou

resources used by the App

(e.g. labels).

Manages the events, and h

the interaction with the use

XML Code

Java Code



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Views can generate events (caused by human inter

that must be managed by the Android-developer.

public void onClick(View arg0) {if (arg0 == Button) {

// Manage Button events}

}

ESEMPIO

B u t t o n

T e x t E d i t



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The Activity Manager is responsib

creating, destroying, managing acti

Activities can be on different states

starting , running , stopped , destroye

paused .

Only one activity can be on the run

state at a time.

Activities are organized on a stack

have an event-driven life cycle (detai



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Main difference between Android-programming and Jav

-programming:

Mobile devices have constrained resource capab

Activity lifetime depends on users’ choice (i.e. change

visibility) as well as on system contraints (i.e. memoryshortage).

Developer must implement lifecycle methods to accou

state changes of each Activity …



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public class MyApp extends Activity {

public void onCreate() { ... }

public void onPause() { ... }

public void onStop() { ... }

public void onDestroy(){ ... }

….

}

Called when the

is created the f

Called when the

is partially visi

Called when th

is no longer v

Called when th

is dismissed.



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Intents: asynchronous messages to activate core A

components (e.g. Activities).

Explicit Intent The component (e.g. Activity1) spec

destination of the intent (e.g. Activity 2).

LOGIN

PASSWORD

Login

marco

**********

Welcome Marco!

Login Intent

A c t i v i t y 1

A c t i v i t y 2



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Intents: asynchronous messages to activate core A

components (e.g. Activities).

Implicit Intent The component (e.g. Activity1) spec

type of the intent (e.g. “ View a video” ).

View

Implicit Intent A c t i v i t y 1

A c t i v i t y 2

A c

t i v i t y 2

Multiple choices

might be availableto the user! }



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Services: like Activities, but run in background and

provide an user interface.

Used for non-interactive tasks (e.g. networking).

Service life-time composed of 3 states:

Starting Destroyed

Running

(on background)

onCreate()

onStart()onDestroy()

Android Components: Content Provi


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Android Components: Content Provi

Each Android application has its own private set o

(managed through files or through SQLite database).

Content Providers: Standard interface to access a

share data among different applications.

DB

APP

insert()

update()

delete()

query()

Content

Provider

e.g. P

Android Components: Broadcast Rece


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Publish/Subscribe

paradigm

Broadcast Rece

An application ca

signaled of extern

events.

Notification type

incoming, SMS

delivery, Wifi netw

detected, etc



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d o d Co po e ts oadcast ece

class WifiReceiver extends BroadcastReceiver {

public void onReceive(Context c, Intent intent) {String s = new StringBuilder();

wifiList = mainWifi.getScanResults();

for(int i = 0; i < wifiList.size(); i++){

s.append(new Integer(i+1).toString() + ".");

s.append((wifiList.get(i)).toString());

s.append("\\n");

}

mainText.setText(sb);

}

}

BROADCAST RECEIVER example

Android Components: System API


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p y

Using the components described so far, Android

applications can then leverage the system API …

Telephony Manager data access (call, SMS, etc)

Sensor management (GPS, accelerometer, etc)

Network connectivity (Wifi, bluetooth, NFC, etc)

Web surfing (HTTP client, WebView, etc)

Storage management (files, SQLite db, etc)

….

SOME EXAMPLEs …

Android Components: Google API


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p g

… or easily interface with other Google services:

Android Application Distribution


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Each Android application is

contained on a single APK fi Java Byte-code (compiled fo

Dalvik JVM )

Resources (e.g. images. videXML layout files)

Libraries (optimal native C/C+

code)

APKFILE

XML

FilesC

Android Application Distribution


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pp

Each application must be sig

through a key before being

distributed.

Applications can be distribu

via Web or via Stores.

Android Play Store: applica

store run by Google … but s

other application stores are

available (they are just norm

applications).

Android Application Security


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Android applications run with a distinct system iden

(Linux user ID and group ID), in an isolated way.

Applications must explicitly share resources and da

They do this by declaring the permissions they ne

additional capabilities.

Applications statically declare the permissions they requ

User must give his/her consensus during the installatio

Documents

MELJUN CORTES ANDROID Lecture Architecture