This document provides an introduction and overview of Android application development. It discusses what Android is, how to install the necessary development tools like Eclipse and the Android SDK, and covers Android application fundamentals such as the different application components and the Android manifest file. It also demonstrates how to create a simple "Hello World" Android application in Eclipse by setting up an Android virtual device, creating an Android project, writing the code, and running the app on the emulator.

1. Introduction to
Application Development
Surendra Bajracharya
Feb 4th, 2013

2. Android Development
Agenda
• What is Android?
• Installation (Eclipse)
• Android Application Fundamentals
• Hello World/Android Demo using Eclipse
• Demo using IntelliJ (Login UI)
• Google Maps application demo
• Comments/Feedback

3. Android Development
What is Android?
• Android is an open source operating system, created
by Google specifically for use on mobile devices (cell
phones and tablets)
• Linux based (2.6 kernel)
• Can be programmed in C/C++ but most app
development is done in Java (Java access to C Libraries
via JNI (Java Native Interface))

4. Android Development
Android System Architecture

5. Android Development
Different Android Versions
Each major release is named in alphabetical order after a dessert or sugary treat; for
example, version 1.5 Cupcake was followed by 1.6 Donut.
Most Android devices to date still run the older OS version 2.3 Gingerbread that was
released on December 6, 2010, due to most lower-end devices still being released with it.

6. Android Development
Installation (30 min ~ 1 hr)
• Eclipse
– www.eclipse.org/downloads/
– 3.5 or later version
– Classic or a Java edition
• Android SDK and Android Development Tools (ADT)
Plugin
– developer.android.com/sdk/requirements.html
• JDK, version 5, 6, or 7

7. Android Development
Android ADT Plugin and SDK
• In Eclipse:
– Navigate to Help | Install New Software
– Follow the instructions on the android site to
install the plugin.
• Point Eclipse to the location of the Android SDK:
– In Eclipse, navigate to Preferences | Android
– Browse to or enter the location in the “SDK Location”
text field.
– Apply, then OK

8. Android Development

9. Android Development
Install packages
•In Eclipse, navigate to Window | Android SDK
Manager
• Install packages from the list
– At least 2.2 and 2.3 for current phone
development
– One tablet package.

10. Android Development

11. Android Development
IntelliJ IDEA (another IDE)
•IntelliJ IDEA 12 offers advanced support for development Android
applications with the latest Android 4.2 SDK.
•Code Assistance
•Refactorings
•Deploy, run and debug Android applications either in emulator or on
a real device.
•UI Designer: With IntelliJ IDEA you can build rich UI for your Android
applications easily by drag and drop. The designer provides support
for layouts, custom components, device profiles, refactorings,
morphing and quick-fixes.

12. Android Development
Android Application Fundamentals
•Android Applications are Collections of reusable
components.
•An Android App may have multiple entry points, and may
use components from other applications.
•In Android, the flow of user interaction across one or
more applications is called a “Task.”

13. Android Development
Application Components
 Activity
◦ Present a visual user interface for one focused endeavor the user can undertake
◦ Example: a list of menu items users can choose from
 Services
◦ Run in the background for an indefinite period of time
◦ Example: calculate and provide the result to activities that need it
 Broadcast Receivers
◦ Receive and react to broadcast announcements
◦ Example: announcements that the time zone has changed
 Content Providers
◦ Store and retrieve data and make it accessible to all applications
◦ Example: Android ships with a number of content providers for common data types
(e.g., audio, video, images, personal contact information, etc.)
 Intents
◦ Hold the content of a message
◦ Example: convey a request for an activity to present an image to the user or let the
user edit some text

14. Android Development
AndroidManifest.xml
•An application's contents are described in the AndroidManifest.xml
file.
•All Activities, Services, Content Providers, and Broadcast Receivers in
an app must have an entry in this file.
•Activities register the Intents they respond to using “Intent Filters”.
•Security permissions, version info, and the minimum sdk version are
also registered in AndroidManifest.xml.

15. Android Development
Resources
• An application's resources are described in .xml files in the /res
path
• Include UI layouts, drawables, values (such as strings and styles),
and even raw .xml files and other data.
• Resources are accessed using Context.getResources() and the
R class
– The R class is defined in R.java, which is generated for each
application.
– Each resource is assigned a public static final int id (compile –
time constant) in the R class.

16. Android Development
Activities
• An Activity is a unit of user interaction within an android
application.
• Activities are represented by the Activity class
– All android apps subclass Activity
– Activities have methods that can be overridden to detect stages
in the activity lifecycle.

17. Android Development
Default android app
package com.sourceallies.helloworldandroidapp; 1. The Activity
import android.app.Activity;
import android.os.Bundle;
public class HelloActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hello);
}
} 2. onCreate is a lifecycle
method of the Activity
3. The content view of the
Activity is set to main.xml

18. Android Development
Lifecycle methods of Activity
•onCreate()
•onStart()
•onResume()
•onPause()
•onRestart()
•onStop()
•onRestart()
All lifecycle methods must
call through to super!
More Information:
http://developer.android.com
/reference/android/app
/Activity.html

19. Android Development
Android Emulator: 2.2 Device

20. Android Development
Hello World/Android Demo...
• Create a new AVD (Android Virtual Device)
• Setup a new Android Project in Eclipse
• Write/run the program
Setting up an AVD
• Open Eclipse and go to the Window tab
• Select the AVD manager from the dropdown
• Once the AVD manager is open, click New
• Name your AVD, and then select a version of the Android API for
the device to use
• Click “Create AVD” – let’s say myAVD
•Can't find AVD or SDK manager in Eclipse - solve it by going to Window ->
Customize Perspective, and under Command Groups Availability tab check the Android SDK
and AVD Manager

21. Android Development
Making an Android Project
• In Eclipse, go to File->New->Project
• Next, open the Android Folder and select Android Project
• Setup your project, so it'll run on your AVD (name it, select API,
etc...)

22. Android Development
Producing an Android App
javac
Java code Byte code
dx
.java .class Dalvik exe
classes.dex aapt
Byte code <xml>
Other .class files AndroidManifest.xml
.apk
Android Package Kit
<str>
Resources

23. Android Development

24. Android Development
Writing the Program
• Open the .java file created by the project
• Initially the code should look like this:

25. Android Development
Writing the Program...continued
After the initial code of the .java file is generated, edit the code so
that it then looks like this:

26. Android Development
Running the App
• Once the program is complete, save it, and then go up to Run.
• Eclipse will then start an appropriate AVD and load the app onto the
emulator
• Once the file is installed on the AVD, it'll launch and you will have
completed your first HELLO world/Android app!

27. Android Development
Running the App
R.java
Do not
modify!
activity_hello.xml
strings.xml

28. Android Development
AndroidManifest.xml

29. Android Development
Important Files
src/HelloActivity.java
Activity which is started when app executes
res/layout/activity_hello.xml
Defines & lays out widgets for the activity
res/values/strings.xml
String constants used by app
gen/R.java (Don’t touch!)
Auto-generated file with identifiers from activity_hello.xml, strings.xml,
and elsewhere
AndroidManifest.xml
Declares all the app’s components
Names libraries app needs to be linked against
Identifies permissions the app expects to be granted

30. Android Development
Various Layouts
http://developer.android.com/resources/tutorials/views/index.html

31. Android Development
Various Widgets
http://developer.android.com/resources/tutorials/views/index.html

32. Android Development
Demo Using IntelliJ IDEA 12.0.1

33. Android Development
Google Maps Demo
https://developers.google.com/maps/documentation/android/v1/mapkey
Android Maps API Key: 0qMq9sUdrh4V367erwY0h76w-hXBG9kzeV1R8bg

34. Android Development

35. Android Development
THANKS!!!
Comments/Feedback
sbajracharya@sourceallies.com