Android chapter01 intro handout

Chapter1‐ 1
Chapter1
AndroidDevelopment
Introduction
VictorMatos
ClevelandStateUniversity
Notesarebasedon:
Ad idDl
A
n
d
ro
id

D
eve
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opers
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UnlockingAndroid
byFrankAbleson,CharlieCollins,andRobi Sen.
ISBN978‐1‐933988‐67‐2
ManningPublications,2009.
1
Chapter1‐ Goals
THEBIGPICTURE
1. WhatisAndroid?
2. Overviewdevelopmentenvironment
2
Chapter1‐ 2
Chapter1‐ Resources

Android’swebpage
/>3
WhatisAndroid?
• Android isanopen‐sourcesoftwareplatform
tdb Gl
d th
O Hdt
crea
t
e
d

b
y
G
oog
l
ean
d

th
e
O
pen
H
an
d
se
t


Alliance.
• Itisprimarilyusedtopowermobilephones.
• Ithasthecapabilitytomakeinroadsinmany
other(non‐phone)embeddedapplication
markets.
4
Chapter1‐ 3
WhatisAndroid?
• Android™consistsofacompletesetof
ft t f bil di
so
ft
warecomponen
t
s
f
ormo
bil
e
d
ev
i
ces
including:
– anoperatingsystem,
– middleware,and
embedded key mobile applications
–
embedded


key

mobile

applications
– alargemarket.
5
WhyAndroid?
Listenfromtheprojectcreators/developers (2.19min)
– NickSears.Co‐founderofAndroid
St HitEi i Di t
–
St
eve
H
orow
it
z.
E
ng
i
neer
i
ng
Di
rec
t
or
– DamMorrill.Developer
– Peisun Wu.EngineeringProjectManager

– ErickTseng.ProjectManager
– Iliyan Malchev.Engineer
– MikeCleron.SoftwareManager
– PerGustafsson.Gr aphicsDesigner.
– etc…
• />d
e
d
• Youwillhearstatementssuchas
“…currentlyitistoodifficulttomakenewproducts…opensoftwarebringsmore
innovation…choices…lowercosts…moreapplicationssuchasfamilyplanner,my
taxes,understandmywifebetter,…”
6
Chapter1‐ 4
WhatisOpenHandsetAlliance?
• Quotingfr omwww.OpenHandsetAlliance.com
page
• “…OpenHandsetAlliance™,agroupof47technology
andmobilecompanieshavecometogethertoaccelerate
innovationinmobileandofferconsumersaricher,less
expensive,andbettermobileexperience.
• TogetherwehavedevelopedAndroid™,thefirst
complete open and free mobile
platform
complete
,
open
,
and


free

mobile

platform
.
• Wearecommittedtocommerciallydeployhandsetsand
servicesusingtheAndroidPlatform.“
7
OpenHandsetAllianceMembers
Operators
SoftwareCo.
Commercializat. Semiconductor HandsetManf
ChinaMobile AscenderCorp. Aplix Audience ACER
ChinaUnicom
KDDICorp.
NTTDoCoMo
SprintNextel
T‐Mobile
TelecomItalia
Telefóni ca
Vodafone
Softbank
eBay
Esmertec
Google
LivingImage
NMSComm.
NuanceComm.
PacketVideo

SkyPop
SONiVOX
Noser Engineering
AstonishingTribe
WindRiverSystems
OmronSoftware
…
Teleca
BroadcomCorp.
IntelCorp.
MarvellTec h.
Group
Nvidia Corp.
Qualcomm
SiRF Tech.Holdings
Synaptics
Texas Instr.
AKM
Semicond
ASUS
HTC
LG
Motorola
Samsung
ASUSTek
Garmin
Huawei Tech
LG
Samsung
…

Ericsson
…
Borqs
AKM

Semicond
.
ARM
Atheros Comm

EMP
Samsung
…
SonyEricsson
Toshiba
8
Chapter1‐ 5
SeeAndroidDevelopers
Shortvideo(4min.)
Sh i
D
Bt
/>Sh
ow
i
ng
D
ave
B
or

t
andDanBorstein,
twomembersofthe
AndroidOpenSource
Projecttalkabout
theproject
.
9
TheAndroidPlatform
Again,whatdidtheysayaboutAndroid?
• Androidisasoftware environmentbuiltformobile
devices.
• Itisnot ahardwareplatform.
• Androidincludes:
• Linuxkernel‐basedOS,
• arichUI,
• telephonefunctionality,
• end‐userapplications,
•
code
libraries,
code

libraries,

• applicationframeworks,
• multimediasupport,
• UserapplicationsarebuiltforAndroidinJava.
10
Chapter1‐ 6

Android’sContext:MobileMarketPlayer$
Stakeholders:
Mobilenetwork operators want
Operators
SoftwareDevice
tolockdowntheirnetworks,
contr ollingandmeteringtraffic.
Device manufacturers wantto
differentiatethemselveswith
features,reliability,andprice
points.
VendorsManufacturers
11
Software vendors wantcomplete
accesstothehardwaretodeliver
cutting‐edgeapplications.
TheMaturingMobileExperience
Notsolongago…Today
Electronictoolsofatypicalbusinesswarrior
1. Phone
2. Pager
3. PDAOrganizer
4. Laptop
5
Portable music player
1. Smartphone
2. Laptop(perhaps!)
5
.
Portable


music

player
6. NoInternet access/
limitedaccess
12
Tomorrow?
Chapter1‐ 7
TheMaturingMobileExperience
Iwant my2015Smartphonetoactas…
Trying to answer Tomorrow ?
1. Phone
2. Pager
3. PDAOrganizer
4. HighQualityCamera(still&video)
5. Po rtablemusicplayer
6. Po rtable TV/VideoPlayer/Radio
7. Laptop
8. PlayStation
9. GPS
10
GlfCdd (b ll i )
Trying

to

answer
:
Tomorrow


?
10
.
G
o
lf

C
a
dd
y
(b
a
ll
retr
i
evertoo
)
11. BookReader(Idon’tread,Itreadstome)
12. Car/Home/OfficeKey
13. RemoteControl(Garage,TV,…)
14. CreditCard/Driver ’sLicense/Passport
15. CashonDemand
16. Cook,housechores
17. Psychologist/Mentor/Adviser
18. ????
13
Androidvs.Competitors
1.AppleInc.

2.Microsoft
3.Nokia
4.Palm
5
Research In Motion
14
5
.
Research

In

Motion
6.Symbian
Chapter1‐ 8
TheSizeof
theMobile
Market
/>/llh
h
/
ce
ll
p
h
one‐overs
h
are
[seeappendix]
1515

AndroidComponents(Stack)
• TheAndroidstackincludesalargearrayof
ft f bil li ti
f
ea
t
ures
f
ormo
bil
eapp
li
ca
ti
ons.
• ItwouldbeeasytoconfuseAndroidwitha
generalpurposecomputingenvironment.
• Allofthemajorcomponentsofacomputing
platform are included
platform

are

included
.
16
Chapter1‐ 9
AndroidComponents
• 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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Tele
p
hon
y
(
hardwarede
p
endent
)

py
( p)
• Bluetooth,EDGE,3G,4G,andWi‐Fi (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
17
AndroidComponents
18
Chapter1‐ 10
AndroidComponents
Video1/3:Android’sArchitecture

PresentedbyMikeCleron,GoogleCorp.(13min)
19
Availableat: />AndroidComponents
Video2/3:Application’sLifeCycle
PresentedbyMikeCleron,GoogleCorp.(8min)
20
Availableat: />Chapter1‐ 11
AndroidComponents
Video3/3:Android’sAPI
PresentedbyMikeCleron,GoogleCorp.(7min)
21
Availableat: />AndroidApplicationFramework
Video:
Inside the
Inside

the

AndroidApplicationFramework
(about52min)
PresentedbyDanMorrill– Google
AtGoogleDeveloperConference
SanFrancisco‐ 2008
Availableat:
htt //it l /it /i /i id
th
did
li ti
fk
htt

p:
//
s
it
es.goog
l
e.com
/
s
it
e
/i
o
/i
ns
id
e‐
th
e‐an
d
ro
id
‐app
li
ca
ti
on‐
f
ramewor
k

22
Androidisdesignedtobefast,powerful,andeasytodevelopfor.Thissession
willdiscusstheAndroidapplicationframeworkindepth,showingyouthe
machinerybehindtheapplicationframework.
explainsthelife‐cycleofanandroidapk.verygood!
Chapter1‐ 12
AndroidComponents
Video:
An Introduction to Android
An

Introduction

to

Android

(about52min)
PresentedbyJasonChen– Google
AtGoogleDeveloperConference
SanFrancisco‐ 2008
Availableat:
http://www youtube com/watch?v x1ZZ
R3p w8
http://www
.
youtube
.
com/watch?v
=

x1ZZ
‐
R3p
_
w8
23
WhyuseLinuxforaphone?
• Linuxkernelisaproven coreplatform.
•
Reliability
is more important than performance when it
•
Reliability
is

more

important

than

performance

when

it

comestoamobilephone,becausevoicecommunicationis
theprimaryuseofaphone.
• Linuxprovidesahardwareabstractionlayer,lettingtheupper

levelsremainunchangeddespitechangesintheunderlying
hardware.
•
As new
accessories
appear on the market
drivers
can be
•
As

new

accessories
appear

on

the

market
,
drivers
can

be

writtenattheLinuxleveltoprovidesupport,justasonother
Linuxplatforms.
24

Chapter1‐ 13
Dalvik VirtualMachine
User applications
ll
core Android applications
•
User

applications
,aswe
ll
as
core

Android

applications
,are
writteninJavaprogramminglanguageandarecompiledinto
bytecodes.
• Androidbytecodesareinterpretedatruntimebyaprocessor
knownastheDalvik virtualmachine.
25
WhyanotherJavaVirtual Machine?
• Androidbytecode filesarelogicallyequivalent
t J
bt d
btth it Ad idt
t
o

J
ava
b
y
t
eco
d
es,
b
u
t

th
eyperm
it

A
n
d
ro
id

t
o
– runitsapplicationsinitsownvirtualenvironmentthatis
freefromSun’slicensingrestrictionsand
– anopenplatformuponwhichGoogle,andpotentiallythe
opensourcecommunity,canimproveasnecessary.
26
Chapter1‐ 14

Dalvik VirtualMachine
Video(61min)
Dlik
VM It l
D
a
l
v
ik
VM

I
n
t
erna
l
s
PresentedbyDanBorstein
AtGoogleDeveloper– 2008
Sanfrancisco
Availableat:
/>27
InsideAndroid:Intents
• AnimportantandrecurringthemeofAndroid
development is the
Intent
development

is


the

Intent
.
• AnIntentinAndroiddescribeswhatyouwanttodo.
• Thismaylooklike
– “Iwanttolookupacontactrecord,”or
– “Pleaselaunchthiswebsite,”or
“
Sh h Od Cfi i S
”
–
“
Sh
owt
h
e
O
r
d
er
C
on
fi
rmat
i
on
S
creen.
”


• Intentsareimportantbecausetheyfacilitate
navigationandrepresentthemostimportantaspect
ofAndroidcoding.
28
Chapter1‐ 15
Intents&IntentFilters
• AnIntent isadeclarationofneed.
• AnIntent ismadeupofvariouspiecesincluding:
– desiredaction orservice,
– data,and
– category ofcomponentthatshouldhandletheintentand
instructionsonhowtolaunchatargetactivity.
A
I t tFilt
i ti dl ti f bilit d
•
A
n
I
n
t
en
tFilt
er
i
sa
t
r
i

gger,a
d
ec
l
ara
ti
ono
f
capa
bilit
yan
d

interestinofferingassistancetothoseinneed.
• AnIntentFilter maybegenericorspecificwithrespectto
whichIntentsitofferstoservice.
29
Intents&IntentFilters
• Anintent isanabstractdescriptionofanoperationtobe
performed.
performed.
• Itsmostsignificantuseisinthelaunchingofactivities,where
itcanbethoughtofasthegluebetweenactivities.
• Theprimarypiecesofinformationinanintentare:
Action Data
Thegeneralactiontobe Thedatatooperateon,suchas
30
performed,suchas:
ACTION_VIEW,
ACTION_EDIT,

ACTION_MAIN,et c.
apersonrecordinthecontacts
database,expressedasaUri.
Chapter1‐ 16
Intents&IntentFilters
SomeexamplesofIntent’saction/datapairsare:
ACTION_VIEW content://contacts/1 ‐‐ Displayinformationaboutthe
personwhoseidentifieris"1".
ACTION_DIAL content://contacts/1 ‐‐ Displaythephonedialerwiththe
personfilledin.
ACTION_VIEW tel:123 ‐‐ Displaythephonedialerwiththegivennumber
filledin
ACTION_DIAL tel:123 ‐‐ Displaythephonedialerwiththegivennumber
31
filledin.
ACTION_EDIT content://contacts/1 ‐‐ Editinformationabouttheperson
whoseidentifieris"1".
ACTION_VIEW content://contacts/ ‐‐ Displayalistofpeople,whichthe
usercanbrowsethrough.
DissectingIntents
1. Componentname Thenameofthecomponentthatshouldhandletheintent(for
example"com.example.project.app.MyActivity1").
2. Action Astringnamingtheactiontobeperformed—or,inthecaseofbroadcast
intents,theactionthattookplaceandisbeingreported(forexample:ACTION_VIEW,
ACTION_CALL,ACTION_TIMEZONE_CHANGED,…).
3. Data TheURIofthedatatobeactedonandtheMIMEtypeofthatdata(forexample
tel:/216 555-1234 , "”
, ).
4. Cate
g

or
y
Astrin
g
containin
g
additionalinformationaboutthekindofcom
p
onentthat
gy
g g p
shouldhandletheintent(forexampleCATEGORY_BROWSABLE,
CATEGORY_LAUNCHER, …
).
5. Extras Key‐valuepairs foradditionalinformationthatshouldbedeliveredtothe
componenthandlingtheintent.
6. Flags ofvarioussorts.
32
Chapter1‐ 17
DeliveringIntents
• AnIntentobjectispassedto
Context startActivity
()
or
Activity startActivityForResult
()
Context
.
startActivity
()

or

Activity
.
startActivityForResult
()
tolaunchanactivityorgetanexistingactivitytodosomething
new(asynchronous &synchronouslyrespectively).
• AnIntentobjectispassedtoContext.startService() toinitiatea
serviceordelivernewinstructionstoanongoingservice.
• AnintentcanbepassedtoContext.bindService() to establisha
connectionbetweenthecallingcomponentandatarget
service.Itcanoptionallyinitiatetheserviceifit'snotalready
running.
33
IntentResolution
Intentscanbedividedintotwogroups:
•
Explicit intents
designate the target component by its name
•
Explicit

intents
designate

the

target


component

by

its

name
,
typicallyusedforanactivitystartingasubordinateserviceor
launchingasisteractivity.
• Implicitintents donotnameatarget(thefieldforthe
componentnameisblank).Implicitintentsareoftenusedto
activatecomponentsinotherapplications.Latebinding
applies
applies
.
WheneverpossibleAndroiddeliversanexplicitintenttoan
instanceofthedesignatedtargetclass.
34
Chapter1‐ 18
ExampleofIntent(1)
• FollowingfragmentscallsanIntent whosejobisto
invoke a built
‐
in task (
ACTION VIEW
) and explore the
invoke

a


built
in

task

(
ACTION
_
VIEW
)

and

explore

the

Contacts availableinthephone.
Intent myIntent = new Intent(
Intent.ACTION_VIEW,
Uri.parse("content://contacts/people"));
startActivity(myIntent);
35
ExampleofIntent(1)
Intentuses
ACTION_VIEW
tosee
Contacts.
36

Chapter1‐ 19
ExampleofIntent(1)
• CompletecodetoseeContacts.
packagematos.cis493;
importandroid.app.Activity;
importandroid.content.Intent;
importandroid.net.Uri;
importandroid.os.Bundle;
publicclassAndDemo1extendsActivity{
/**showcontactlist*/
@Override
public void
onCreate
(Bundle
savedInstanceState
) {
37
public

void

onCreate
(Bundle

savedInstanceState
)

{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

IntentmyIntent =newIntent( Intent.ACTION_VIEW,Uri.parse( "content://contacts/people"));
startActivity(myIntent);
}
}
ExampleofIntent(2)
• FollowingIntent usesbuilt‐intask(ACTION_VIEW)to
explore a web page
explore

a

web

page

(seenewUrivalue)
Intent myIntent = new Intent(
Intent.ACTION_VIEW,
Uri.parse(""));
startActivity(myIntent);
38
Chapter1‐ 20
ExampleofIntent(3)
• FollowingIntent usesbuilt‐intask(ACTION_VIEW)to
make a phone call
make

a

phone


call
(seenewUrivalue)
Intent myIntent = new Intent(
Intent.ACTION_VIEW,
Uri.parse("tel:/216 555-1234"));
startActivity(myIntent);
39
IntentFilters
• TheIntentFilter definestherelationshipbetweenthe
Intentandtheapplication.
• IntentFilters canbespecifictothedataportionof
theIntent,theactionportion,orboth.
• IntentFilters alsocontainafieldknownasacategory.
Acategoryhelpsclassifytheaction.
• Forexample,thecategorynamed
CATEGORY_LAUNCHER
instructsAndroidthattheActivitycontainingthis
IntentFilter shouldbevisibleinthehomescreen.
40
Chapter1‐ 21
IntentFilters
• WhenanIntent isdispatched,thesystemevaluates
theavailableActivities,Services,andregistered
BroadcastReceivers androutestheIntenttothemost
appropriate recipient(seenextFigure).
41
IntentFilters
42
Chapter1‐ 22

IntentFilters
• Toinformthes
y
stemwhichim
p
licit intentsthe
y
can
y
p
y
handle,activities,services,andbroadcastreceivers can
haveoneormoreintentfilters.
• Eachfilterdescribesacapabilitythatthecomponentis
willingtoreceive.
43
• Anexplicit intentisalwaysdeliveredtoitstarget,nomatter
whatitcontains;thefilterisnotconsulted.
• Butanimplicitintentisdeliveredtoacomponentonlyifit
canpassthroughoneofthecomponent'sfilters.
IntentFilters
• IntentFilters a reoftendefinedinana
pp
lication’s
pp
AndroidManifest.xmlwiththe<intent‐filter> tag.
<intent‐filter...>
<actionandroid:name="codeandroid.intent.action.MAIN"/>
<categoryandroid:name="codeandroid.intent.category.LAUNCHER"/>
<categoryandroid:name="android.intent.category.BROWSABLE"/>

<dataandroid:type="video/mpeg"android:scheme="http".../>
<data
android type
"audio/mpeg"
android scheme
"http" />
44
<data

android
:
type
=
"audio/mpeg"

android
:
scheme
=
"http"
...
/>

...
</intent‐filter>
Chapter1‐ 23
AndroidApplications
• EachAndroid applicationrunsinitsownLinux
process.
• Anapplicationconsistsofacombinationofsoftware

componentsincluding:
– Activities
– Services
–
BroadcastReceivers
– ContentProviders
45
AndroidApplications
Structureof
til
a
t
yp
i
ca
l

Android
Application
46
Chapter1‐ 24
AndroidServices
• AService isanapplicationcomponentthatruns
in the background not interacting with the user
in

the

background
,

not

interacting

with

the

user
,
foranindefiniteperiodoftime.
• Eachserviceclassmusthav e acorresponding
<service> declarationinitspackage's
AndroidManifest.xml.
•
Services can be started/stopped with
Services

can

be

started/stopped

with

– Context.startService()and
– Context.bindService().
– stopService(…)andunbindService(…)
47

AndroidServices
• Services,likeotherapplicationobjects,runin
th i th d f th i hti
th
ema
i
n
th
rea
d
o
f

th
e
i
r
h
os
ti
ngprocess.
• Thismeansthat,ifyourserviceisgoingtodo
anyCPUintensive(suchasMP3playback)or
blocking (such as networking RSS exchange)
blocking

(such

as


networking
,
RSS

exchange)

operations,itshouldspawnitsownthreadin
whichtodothatwork
48
Chapter1‐ 25
AndroidServices
Service1Class
package matos.service;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class Service1 extends Service implements Runnable {
private int counter = 0;
@Override
public void onCreate() {
super.onCreate();
Thread aThread = new Thread(this);
aThread.start();
}
public void run() {
while (true) {
t
r
y

{
y
{
Log.i("service1", "service1 firing : # " + counter++);
Thread.sleep(10000); //this is where the heavy-duty computing occurs
} catch (Exception ee) {
Log.e("service1", ee.getMessage());
}
}
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
49
AndroidServices
//Service1Driver
packagematos.service;
dd
importan
d
roi
d
.app.Activity;
importandroid.content.Intent;
importandroid.os.Bundle;
publicclassService1Driver extendsActivity{
@Override
publicvoidonCreate(BundlesavedInstanceState){

super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//invokingtheservice
Intentservice1Intent=newIntent(this,Service1.class);
startService(service1Intent);
//dosomeworkhere….
}
}//Service1Driver
50