The document discusses the different building blocks of an Android application including activities, services, broadcast receivers, and content providers. It provides details on broadcast receivers, describing them as components that respond to system-wide broadcasts and application-initiated broadcasts. The document gives an example of using a broadcast receiver to capture the SMS receive event and launch an activity to display the SMS with an option to reply. It also discusses programmatically sending SMS from an application.

1. Android application development
Broadcast
Receiver

2. Application Building Blocks
• UI Component Typically
Corresponding to one screen.
Activity
• Responds to notifications or status
changes. Can wake up your process.
IntentReceiver
• Faceless task that runs in the
background.
Service
ContentProvider • Enable applications to share data.

3. Android Application Anatomy
Activities
1. Provides User Interface
2. Usually represents a Single Screen
3. Can contain one/more Views
4. Extends the Activity Base class
Services
1. No User Interface
2. Runs in Background
3. Extends the Service Base Class
Application= Set of Android Components
Content Provider
1. Makes application data available
to other apps
2. Data stored in SQLite database
3. Extends the ContentProvider
Base class
Intent/Broadcast Receiver
1. Receives and Reacts to broadcast
Intents
2. No UI but can start an Activity
3. Extends the BroadcastReceiver
Base Class

4. Broadcast Receivers
1. A broadcast receiver is a component that responds to system-wide
Broadcast announcements.
2. Many broadcasts originate from the system—for example, a
Broadcast announcing that the screen has turned off, the battery
is low, or a picture was captured or an SMS is received.
3. Applications can also initiate broadcasts—for example, to let other
Applications know that some data has been downloaded to the
device and is available for them to use.
4. 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.
5. More commonly, though, a broadcast receiver is just a "gateway" to
other components and is intended to do a very minimal amount of
work. For instance, it might initiate a service/or start an activity to
perform some work based on the event.

5. Android Application Anatomy
UI
Activity 1
Service
Activity 2
BroadcastReceiver
OS
Intents
1. Directed Intents
2. Broadcast Intents
BIG PICTURE

6. Broadcast Receivers
1. We’ll use a Broadcast Receiver to capture SMS receive event
2. We capture the SMS receive event and launch an Activity to show the sms and give user
an option to reply the SMS
Activity
OS BroadcastReceiver

7. Broadcast Receivers
1. Create a new project BroadcastReceiverDemo
2. A broadcast receiver is implemented as a subclass of BroadcastReceiver and each
broadcast is delivered as an Intent object. In this case the intent is detected by
android.provider.Telephony.SMS_RECEIVED
To do this we’ll create a class SMSReceiver that extends BroadcastReceiver class
and define the method onReceive()
BroadcastReceiver

8. Broadcast Receivers (Contd.)
3. We also need to add SMSReceiver as receiver of a particular Intent (SMS received)
which is identified by android.provider.Telephony.SMS_RECEIVED
BroadcastReceiver

9. Broadcast Receivers (Contd.)
4. Also we have to add permission for receiving SMS
BroadcastReceiver

10. Broadcast Receivers (Contd.)
5. Now we run the application
6. Now we use emulator control to send sms

11. Receiving SMS
Bundle bundle = intent.getExtras();
SmsMessage[] msgs = null;
String str = "";
String address="";
if (bundle != null)
{
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsMessage[pdus.length];
for (int i=0; i<msgs.length; i++)
{
msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
str += "SMS from " + msgs[i].getOriginatingAddress();
str += " :";
str += msgs[i].getMessageBody().toString();
str += "n";
address=msgs[i].getOriginatingAddress();
Toast.makeText(context, str, Toast.LENGTH_LONG).show();
}

12. Sending SMS
1. Add permission in menifest.xml
2. We add the following code for sending SMS from anywhere of our application

13. Exercise
We’ll create a replica of SMS application of Android
1. Application will have a basic TabActivity with 3 tabs (Activities)
1. Send- will give user option to send sms (2 input fields for
number and text)
All sent SMS will be saved in database
2. Inbox- (List Activity) which will fetch all received SMS from
database
3. Sent- (ListActivity) which will fetch all sent SMS
2. A broadcast receiver which will receive SMS and save them to
database

14. Thank You.