Introduction to Android Application_modified

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Introduction to AndroidApplication

Kyuseok Shim

EECS, SNU


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Android Architecture

Component diagram of the Android operating system Today, we are focusing on the application part 2

briefintroduction

somedetails


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Core Libraries

A set of C/C++ libraries, which are built on Linux Kernel System C Library

Standard C library, tuned for embedded Linux

Media Libraries Playback and recording of audio and video

Surface Manager Display subsystem management Composites 2D/3D graphic layers

LibWebCore Embeddable web browser

SGL/3D Libraries 2D graphic engine, hardware 3D Acceleration

SQLite Relational database engine

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Application Framework

Application Framework provides services and systems Use device hardware, access location information, set alarms,

add notifications to the status bar, and more

Application framework is composed of

Views View is a area for drawing and event handling e.g. buttons, lists, grids, and even web browser

Content Providers Access or share data among applications

e.g. contacts, and MediaStore

Resource Manager Access non-code resources e.g. localized strings, images, and layout files

Notification Manager Display alerts in the status bar

Activity Manager Manages lifecycles of applications Provides a common navigation 4


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Applications

Built on application framework An app listens phone state changes via Telephony Manager An app exploits an ImageView object from View System A new activity has Activity Manager change states of others

Written in Java programming Language Core applications shipped with Android

, , , , ,

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get, listen, request,

?

dont carewhat happens

actually


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Application Components

Application building blocks Activities

A single screen with a user interface Enable to draw and handle events

Most frequently used, undoubtedly

Start from users activation

End when it is closed by user

Similar to a full window in MS Windows Services

Contents Providers

Broadcast Receivers6

Activity Stack


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Application building blocks

Activities

Services Run in background to perform long-

running operations

Once started, last until it is terminated

e.g. messenger service, music player Contents Providers

Broadcast Receivers

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Running Services

Check if theresa new message

Monitoringphone usage

Playing music

in background


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Activities

Services Contents Providers

Manages shared set of application data

Other applications can read and even

modify data Once registered, last until it is terminated

e.g. Contacts, Settings, Calendar provider

Broadcast Receivers8

RegisteredContents Providers

ScheduleProvider

read

add


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Activities

Services Contents Providers

Broadcast Receivers

Responds to broad-cast events

low battery, SMS received,

Start when the event is received

End after handling the event

e.g. alarm, phone call, SMS notifier9

Phone

call

Phone callreceiver

broadcast

start activityfor phone call

Alarm

Alarmreceiver

start activityfor alarmbroadcast

Your appsAlarmReceiver

?

anythingyou want to do

about this alarm


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Application building blocks Activities

A single screen with a user interface

Services

Runs in background to perform long-running operations Contents Providers

Manages shared set of application data

Broadcast Receivers Responds to broad-cast events

You dont have to write all these components Required components depend on your apps purpose

A music player requires activities and services A dictionary consists ofactivities and content providers A SMS manager needs activities and broadcast receivers

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Communications Between

Application Components Android application can start another applicationscomponent Suppose you are going to make SNS app, and this app

requires updating photos from camera Which one of the following choices is better than others?

Writing code for taking pictures Incorporate another code Activate the existing well-made camera app and get result from it

Intent is a message object Description of operation to be performed Mostly used for launching another application

e.g. Is there anyone can play a music?

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Id like to run an appcan get music

Intent

Run the selected appas the description of this intent


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Summary

Android applications are built onAndroid application framework with

fruitful functionalitiesAndroid applications consist of four

components: Activity, Contents Provider,Service, and Broadcast Receiver

Android applications can activate orcommunicate with another applicationscomponent

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Android ApplicationDevelopment: Get Started

Kyuseok Shim

EECS, SNU


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Installation list

Java Development Kit(JDK)

For building java source code

Android SDK Contains Core SDK Tools and Components

Eclipse IDE for Java

For convenience in development

Android Development Tool(ADT)

Eclipse plug-in offered by android

Helps Eclipse to create and debug applications14


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Install Android SDK

Download Android SDK http://developer.android.com/sdk/index.html

Execute the downloaded file to install If installer failed to find JDK under 64bit Windows, then

click Back and Next button again Choose packages and install them, default is enough

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Select packages

to install


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Install Eclipse IDE

Download Eclipse IDE for Java http://www.eclipse.org/downloads/

Unzip the downloaded file Execute eclipse.exe to open IDE Setworkspace to your working directory

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Your working directory


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Install Eclipse ADT

Start eclipse SelectHelp >Install New Software Click Add and Add Repository with the

following URL https://dl-ssl.google.com/android/eclipse/

Accept the license agreement and finish

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ADT repository URL


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Configure Eclipse more

Have Eclipse know where the Android SDK is

Open the menu Windows>Preferences

Set SDK Location to your Android SDK path

Apply to list available android targets

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Your Android SDK path


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Create Android Virtual Device

Android Virtual Device(AVD) is a android emulator acts like a real device except for a few limitations

Create your own AVD Open Window>Android SDK and AVD Manager Select device target and decide the size of SD Card Create AVD and try starting the device

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Donut(1.6)Eclair(2.1)Froyo(2.2)

Gingerbread(2.3)Honeycomb(3.0)


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Hello Android!

Try creating a new android project File>New>Project, Select Android Project Select build target Write down properties

Application name: the title of this app Hello Android

Package name: where sources to be located eecs.seminar.shim

Create Activity: create with a new activity Main

Min SDK Version: minimum SDK version to guarantee 7 for eclair

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Run Hello Android!

Run this application by menu Run>Run or button on toolbar or

Ctrl+F11 Your AVD displays the result like below

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Basic Structure of Hello Android

HelloAndroid project consists ofSrc folder

Java files to be implemented

gen folderAuto-generated java files

assets folderAny files you want to ship with

res folder Resources such as images, layouts and fonts

AndroidManifest.xml file Essential information about the application

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Strings of Hello Android

Where does this string come from?

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Where can I modify it to Hello Android? res>values folder contains string resources

To see the string, open strings.xml file Modify the value of field hello to Hello Android

Theres the other field app_name, the title


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Layout of Hello Android

If so, where is the point the stringis loaded? res>layout folder contains layout files

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To see the current layout, open main.xml in layout folder Moreover, double-clicking on the text leads to open a text editor

for layout Sure, the android:text=@string/hello might be Hello Android


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More about Layout

Android provides lots of layout and widget objects Layout object

A container of other layout and widget object Arrange containing widgets in an order e.g. LinearLayout, RelativeLayout, TabLayout,

Widget object UI element displayed on screen Corresponds to the event such as clicking, mouse over, e.g. TextView, Button, DatePicker, Gallery, WebView,

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Layouts Widgets


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Prepare for Interactive Hello Android

Just setting up the layout is not enough to makean android application

Instead of a boring app, to make more interactiveapp, lets place a button on screen

Open main.xml in res>layout folder Drag Button to the screen Double-click the button to open the text layout editor

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The id of this buttonis button1


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Interactive Hello Android

To have the button listen a event, thesource code Main.java should be rewritten

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import necessaries

get a reference to the button

whenever the button is clicked,

it shows a message box called Toast


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Summary

To develop android applications, it isrequired to install JDK, Android SDK,Eclipse IDE, Eclipse ADT plug-in

To test android applications, usuallyAndroid Virtual Device(AVD) is enough

Android offers a variety of UI elements

and containers for layoutAll the Android UI elements can handle

events such as click and touch for userinteraction

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Android ApplicationDevelopment: Debugging

Kyuseok Shim

EECS, SNU


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Debugging

Most software developers suffers from thefault or malfunction of their program

Debugging is the process finding errors orbugs and making the program run in thedesired way

Debugger is a program used to test and

debug other programs, nowadaysdebuggers become important to save timeand effort for software development

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Debugging Tools in Android

Android Debug Bridge(ADB) and Dalvik DebugMonitor Server(DDMS) are debugging tools Shipped with Android SDK Let you manage the state of Android device Provides many debugging capabilities

Examining memory, methods, and log Emulating phone operations and location Installing an application, and copying files Printing log and dump data

Issuing a shell command in devices Eclipse ADT plug-in performs based on ADB

and DDMS e.g. Running an app in Eclipse consists of two ADB

commands: install and start

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Debugging in Android

Running in debug mode By clicking or menu

Run>Debug

Uses Java debug perspectiveas usual Thanks to ADT and debugger

tools in SDK

Available debugger features Setting breakpoints

Step-by-step execution

Watching variables

Check the current call stack

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Breaks herecurrently

Call Stack Variables

Source View


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Logging in Android, System

Android Logging system collects debug outputfrom various applications Especially, collecting system errors is important

Android LogCat dumps a log collected ADT provides LogCat window for Eclipse

Window>Show View>Other, Android>LogCat

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Logging in Android, Your App.

Log is a logging class Can be utilized in your code Prints out messages to the LogCat

Similar to printf or std::cout in console program

5 methods for 5 different priorities Log.v, Log.d, Log.i, Log.w, Log.e Verbose, debug, information, warning, error

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Other tools from Android SDK

Window>Show View>Other/Android

File Explorer Pull, push, and delete files

Emulator Control Changes telephone state

Spoofs calls or SMS Sets the location manually

Devices List available devices Debug and stop a process Capture the screen of a device

Layout View/Tree View Displays the current placement of widgets

Shows hierarchical relationships between layouts 36


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Introduction to Android Application_modified

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