Download - Android Step by Step
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BuildingBuildingHelloWorldHelloWorld
Android ApplicationAndroid Application
Step by Step.Step by Step.
Sang ShinSang ShinMichle GarocheMichle Garoche
www.javapassion.comwww.javapassion.comLearn with Passion!Learn with Passion!
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Disclaimer
Portions of this presentation are modificationsbased on work created and shared by theAndroid Open Source Project
> http://code.google.com/policies.html
They are used according to terms described inthe Creative Commons 2.5 Attribution License
> http://creativecommons.org/licenses/by/2.5/
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Goals of This Presentation
Get you started with Android applicationdevelopment
Get you know the development environment
>
Will focus on Eclipse-based Android developmentenvironment (instead of command-line-basedone)
Get you be exposed to the basic building blocksof an Android application in a cursory manner
> The details will be covered in the rest of thecourse
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Topics
Installation and configuration
Building blocks of Android application
> Activities
>
Layout resource files> AndroidManifest.xml
> Resource files - strings.xml
> R.java
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Installation &Installation &
ConfigurationConfiguration
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Software Needed
JDK (Java Development Kit)
> Android application is Java application
Eclipse IDE>
Editor, Debugger, profiler, deployment Android SDK
> Libraries, samples, documentation, handsetemulators, debugger, command line tools
Eclipse ADT (Android Development Tools) plug-in
> Give you a powerful, integrated develpmentenvironment
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Creating Android Project using Eclipse
Automatic creationbuilding blocks of anAndroid application
> Starting Activity
class> Layout resource file
> AndroidManifest.xml
> strings.xml
> R.java> Android library
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Building Blocks ofBuilding Blocks of
Android ApplicationAndroid Application
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Building Blocks of Android Application
Activity classes
Layout resource files
Resource files>
strings.xml AndroidManifest.xml
R.java (automatically created from resourcefiles)
Android library (automatically configured)
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Building Blocks of Android Application
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Activity Class
Each Activity class typically represents a screen
> Like a JSP page in a Web application
The onCreate() method of Activity class getscalled by the Android system when yourActivity starts> You create your UI inside the onCreate() method
Every Activity has to be described in theAndroidManifest.xml file
An Activity is typically chosen as a starting oneof your application - like a class that has amain() method in Java
> Special configuration in AndroidManifest.xml
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Activity Class Example
package com.javapassion;
import android.app.Activity;import android.os.Bundle;
publicclass HelloWorldActivity extends Activity {
/** Called when the activity is first created. */ @Override publicvoid onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);
//Create UI using Layout resource filesetContentView(R.layout.main);
}}
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Layout Resource Files
Every screen has a corresponding layoutresource file> Unless you create UI programmatically
Each activity class specifies which layoutresource file to use for each screen itrepresents
> Using setContentView(R.layout.main);
Are located under /res/layoutdirectory
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Layout Resource File Example
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Resource Files - strings.xml
Let you define the text strings of yourapplications in a well-known file> Rather than in Java code
> Rather than in Layout resource files
The strings are then referred to through thenames assigned to them
> The mapping is done through R.java
Located under /res/values directory
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AndroidManifest.xml file
Every application must have a manifest filecalled AndroidManifest.xml file (with preciselythat name) in its root directory.
The manifest presents essential information
about the application to the Android system,information the system must have before it canrun any of the application's code.
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Info. in AndroidManifest.xml file
Java package for the application.> The package name serves as a unique identifier for
the application.
Activities
> One activity is designated as a starting Activity
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AndroidManifest.xml
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R.java
Automatically created by Android system for allresources defined
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R.java
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Thank you!Thank you!
Sang ShinSang ShinMichle GarocheMichle Garoche
www.javapassion.comwww.javapassion.comLearn with Passion!Learn with Passion!