1. Android Programming Lecture 9
Testing notes
Service and Broadcast Receiver

2. Sample App: Music Player

3. Sample App (1/7) Click on the icon and get the startup
Launcher activity is started by the sending of a special intent – the Launcher intent
Application Manifest declares which Java class accepts the launcher intent

4. Sample App (2/7) Left side is a menu for different views
The activity has a few fragments (sub- activity) for navigation
Youtube tutorial
Click on
My Library

5. Sample App (3/7)
Click Albums to get into the Albums sub-activity (fragment)
Tab UI can be easily achieved using Tab Host ViewGroup
Click
an album name

6. Sample App (4/7) Shows the album in a different activity
Click on a track for immediate playback
Click adds it to the task bar
Launches a service to play
Click on the back button to return to the previous activity
Android maintains a stack of activities for “back”
Refer to:

7. Sample App (5/7) Playback continues, even if the user navigates away
Even if the user locks the phone, as long as the user does not shut down the app

8. Sample App (6/7) Service can be controlled by a widget when locked
Also from the notification bar
By clicking the notification bar, we can get back to the music player

9. Sample App (7/7) Service interrupted when a call come
A Broadcast Event that all the (registered) apps would receive!
Resumes after the call hangs up

11. App Components Activity Intent Service ContentProvider
Application= Set of Android Components
Intent
Activity
UI Component typically corresponding to one screen.
BroadcastReceiver
Responds to notifications or status changes. Can wake up your process.
Service
Faceless task that runs in the background.
ContentProvider
Enable applications to share data.

12. App Components Activities Application= Set of Android Components
Provides User Interface
Usually represents a Single Screen
Can contain one/more Views
Extends the Activity Base class

13. Connected with Intents
App Components
Application= Set of Android Components
Activities
Provides User Interface
Usually represents a Single Screen
Can contain one/more Views
Extends the Activity Base class
Services
No User Interface
Runs in Background to handle long running operations
Connected with Intents
Faceless task that runs in the background for long-running operations

14. Intent/Broadcast Receiver
App Components
Application= Set of Android Components
Activities
Provides User Interface
Usually represents a Single Screen
Can contain one/more Views
Extends the Activity Base class
Connected with Intents
Responds to notifications /status changes/events
Incoming phone call
Battery low
Alarm …
Intent/Broadcast Receiver
Receives and Reacts to broadcast Intents
No UI but can start an Activity

15. Connected with Intents
App Components
Application= Set of Android Components
Activities
Provides User Interface
Usually represents a Single Screen
Can contain one/more Views
Extends the Activity Base class
Connected with Intents
Content Provider
Makes application data available to other apps
Data stored in SQLite database
Enable applications to share data
Retrieve icon, songs from other music app
Retrieve contact books to recommend music to friends

16. Intent/Broadcast Receiver
App Components
Application= Set of Android Components
Activities
Provides User Interface
Usually represents a Single Screen
Can contain one/more Views
Extends the Activity Base class
Services
No User Interface
Runs in Background to handle long running operations
Connected with Intents
Intent/Broadcast Receiver
Receives and Reacts to broadcast Intents
No UI but can start an Activity
Content Provider
Makes application data available to other apps
Data stored in SQLite database

17. Service

18. Service
An application component that can perform long- running operations in the background and does not provide a user interface
Load music to play
Download, decode and show an
Download a html from Internet to display
Why Service?
Put the time-consuming job in the background

40. What a good should provide?
Desirable Functions
Attractive UI
Good user experience
Quick response and reliable (never crash)
Secure and safe to use

41. Using Service Step 1: Create custom class extended from Service class
Reason to use custom class
We need to override the callback functions to specify the behavior of app

42. Using Service Step 2: Use the custom in the Activity to launch service
public class MainActivity extends Activity {
...
// Inside the method where you need to launch the service
// Create the service object
MyService myService = new MyService();
// Create the Intent for launching the service
Intent intent = new Intent(MainActivity.this, MediaPlayerService.class);
// Call startService() method to start the service
MainActivity.this.startService(intent);
MainActivity.this.stopService(intent); }

43. Using Service
Step 3: Register the Service class in AndroidManifest.xml
<manifest >
. . .
<application . . .>
<service android:name=".MyService" > </service>
</application>
</manifest>

44. Lifecycle of Service
Android provides different callback functions at different states of a service
Developer can override the methods to specify the app behaviors like what we do in Activity
Android provides two type of services:
Started services
Bound services

45. MainActivity.this.startService(intent);
MainActivity.this.stopService(intent);

46. Bound Service
A bound service offers a client-server interface that allows components to interact with the service
Using custom class
Using a messenger
Using AIDL (Android Interface Definition Language)

47. Broadcast Receiver

48. Broadcast Receiver Responds to system-wide Broadcast announcements.
Many broadcasts originate from the system—for example, screen has turned off, the battery is low, or a picture was captured or an SMS is received.
Applications can also initiate broadcasts.
Although broadcast receivers don't display a user interface, they may create a status bar notification to alert the user when a broadcast event occurs.

49. Using Broadcast Receiver
Step 1: Create custom class extended from the Broadcast Receiver class
public class MyReciever extends BroadcastReceiver {
// callback function called when the broadcast event is captured
@Override
public void onReceive(Context context, Intent intent) {
// Override the method }
Reason to use custom class
We need to override the callback functions to specify the behavior of app

50. Using Broadcast Receiver
Step 2: Register as the broadcast receiver in Java
or declare in AndroidManefist.xml
public class MainActivity extends Activity {
. . .
// Create an IntentFilter object (in Java)
IntentFilter filter = new IntentFilter();
// Specify the Action of the Intent Filter
filter.addAction(Intent.ACTION_CAMERA_BUTTON);
// Create the receiver object
reciever = new MyReciever(MainActivity.this);
// Register the receiver
MainActivity.this.registerReceiver(reciever, filter);
// Unregister Register the receiver
MainActivity.this.unregisterReceiver(reciever); }

51. Using Broadcast Receiver
Step 2: Register as the broadcast receiver in Java
or declare in AndroidManefist.xml
<manifest >
. . .
<application . . .>
<receiver android:name=".MyReceiver" > </receiver>
</application>
</manifest>

52. Summary What is an Activity? What is a Service?
What is a Broadcast Receiver?
What is a Content Provider?
How to enable a service inside an activity?
How to enable a broadcast receiver inside an activity?

53. Recommended Reading
Vogella tutorial on Services, BroadcastReceiver and NotificationManager
Android Developer Site:
Services: ces.html
Content Provider: ontent-providers.html