1. Android Application Development 1 6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 1

2. What is Android?
An open source Linux-based operating system intended for mobile computing platforms
Includes a Java API for developing applications
It is not a device or product
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 2

3. 6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 3

4. What Skills Will Students Learn?
Reinforce the basics: OOP, decomposition, etc.
Separation of UI design and functionality
XML and resource files
Events and Listeners
Callback methods
Threads
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 4

5. Android vs. iPhone Java vs. Objective-C
Direct install vs. Marketplace vs. App Store
Open source?
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 5

6. What Should Students Already Know?
Java!
inheritance, method overriding
interfaces, casting
exceptions
debugging
reading API documentation
Eclipse
easy to pick up quickly, though
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 6

7. Do I Need Phones?
The emulator that is part of the Android toolset for Eclipse is quite good (though a bit slow)
You may be able to get free “developer phones” from Google
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 7

8. Online Resources developer.android.com
code.google.com/p/apps-for-android/
stackoverflow.com
videos from Google I/O conferences
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 8

9. Concepts: activity, service, broadcast receiver, content provider,
Understand applications and their components
Concepts:
activity,
service,
broadcast receiver,
content provider,
intent,
AndroidManifest
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

10. Applications
Written in Java (it’s possible to write native code – will not cover that here)
Good separation (and corresponding security) from other applications:
Each application runs in its own process
Each process has its own separate VM
Each application is assigned a unique Linux user ID – by default files of that application are only visible to that application (can be explicitly exported)
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

11. Application Components
Activities – visual user interface focused on a single thing a user can do
Services – no visual interface – they run in the background
Broadcast Receivers – receive and react to broadcast announcements
Content Providers – allow data exchange between applications
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

12. Activities Basic component of most applications
Most applications have several activities that start each other as needed
Each is implemented as a subclass of the base Activity class
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

13. Activities – The View
Each activity has a default window to draw in (although it may prompt for dialogs or notifications)
The content of the window is a view or a group of views (derived from View or ViewGroup)
Example of views: buttons, text fields, scroll bars, menu items, check boxes, etc.
View(Group) made visible via Activity.setContentView() method.
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

14. Services Does not have a visual interface
Runs in the background indefinitely
Examples
Network Downloads
Playing Music
TCP/UDP Server
You can bind to a an existing service and control its operation
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

15. Broadcast Receivers Receive and react to broadcast announcements
Extend the class BroadcastReceiver
Examples of broadcasts:
Low battery, power connected, shutdown, timezone changed, etc.
Other applications can initiate broadcasts
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

16. Content Providers
Makes some of the application data available to other applications
It’s the only way to transfer data between applications in Android (no shared files, shared memory, pipes, etc.)
Extends the class ContentProvider;
Other applications use a ContentResolver object to access the data provided via a ContentProvider
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

17. Intents An intent is an Intent object with a message content.
Activities, services and broadcast receivers are started by intents. ContentProviders are started by ContentResolvers:
An activity is started by Context.startActivity(Intent intent) or Activity.startActivityForResult(Intent intent, int RequestCode)
A service is started by Context.startService(Intent service)
An application can initiate a broadcast by using an Intent in any of Context.sendBroadcast(Intent intent), Context.sendOrderedBroadcast(), and Context.sendStickyBroadcast()
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

18. Shutting down components
Activities
Can terminate itself via finish();
Can terminate other activities it started via finishActivity();
Services
Can terminate via stopSelf(); or Context.stopService();
Content Providers
Are only active when responding to ContentResolvers
Broadcast Receivers
Are only active when responding to broadcasts
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

19. Android Manifest
Its main purpose in life is to declare the components to the system:
<?xml version="1.0" encoding="utf-8"?> <manifest >     <application >         <activity android:name="com.example.project.FreneticActivity"                                                        >         </activity>             </application> </manifest>
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

20. Intent Filters
Declare Intents handled by the current application (in the AndroidManifest):
<?xml version="1.0" encoding="utf-8"?> <manifest >     <application >         <activity android:name="com.example.project.FreneticActivity"                                                        >             <intent-filter >                 <action android:name="android.intent.action.MAIN" />                 <category android:name="android.intent.category.LAUNCHER" />             </intent-filter>             <intent-filter >                 <action android:name="com.example.project.BOUNCE" />                 <data android:mimeType="image/jpeg" />                 <category android:name="android.intent.category.DEFAULT" />             </intent-filter>         </activity>             </application> </manifest>
Shows in the Launcher and is the main activity to start
Handles JPEG images in some way
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID

21. “Hello, Android”
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 21

22. Creating Your First(?) Android App
Set up your development environment
Create a new Android project in Eclipse
Run it in the emulator
Hilarity ensues
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 22

23. 1. Set Up Your Android Environment
Install Eclipse
Install Android SDK (Android libraries)
Install ADT plugin (Android development tools)
Create AVD (Android virtual device)
We’ve already done this for you!!
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 23

24. 2. Create an Android Project in Eclipse
File → New → Project
Select “Android Project”
Fill in Project details...
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 24

25. Directory name Android version Java package Name that appears
on device
Class to
automatically
create
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 25

26. 3. Run the Android Application
Run → Run (or click the “Run” button)
Select “Android Application”
The emulator may take a few minutes to start, so be patient!
You don't need to restart the emulator when you have a new version of your application
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 26

27. 6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 27

28. Source code Auto-generated code String constants UI layout
Configuration
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 28

29. HelloAndroid.java 1 public class HelloAndroid extends Activity {
2  /** Called when the activity is first created. */ 3 
4    public void onCreate(Bundle savedInstanceState)
5 {
6      super.onCreate(savedInstanceState);
7        setContentView(R.layout.main);
8    }
9 }
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 29

30. main.xml 1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout
3 xmlns:android="
4 android:orientation="vertical"
5 android:layout_width="fill_parent"
6 android:layout_height="fill_parent"
7 >
8 <TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
11 "
/>
13 </LinearLayout>
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 30

31. strings.xml 1 <?xml version="1.0" encoding="utf-8"?>
2 <resources>
3 <string name="hello">Hello World, HelloAndroid!
4 </string>
5 <string name="app_name">Hello, Android</string>
6 </resources>
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 31

32. AndroidManifest.xml 1 <?xml version="1.0" encoding="utf-8"?>
3 xmlns:android="
4 package="edu.upenn.cis542"
5 android:versionCode="1"
6 android:versionName="1.0">
7 <application 8
<activity android:name=".HelloAndroid" 10
<intent-filter>
<action
android:name="android.intent.action.MAIN" />
<category
android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
18 </application>
19 </manifest>
6 May 2018
S.RENUKADEVI/AP/SCD/INTRODUCTION TO ANDROID 32