This document discusses various Android programming concepts including context, activities, bundles, contacts provider, telephony manager, phone state listener, incoming phone calls, sending and receiving SMS, and Bluetooth setup. Context provides information about the application environment and is used to access common resources and components. An activity extends context and views get their context usually from the activity context. Bundles are used to parcel data between components while the contacts provider and telephony manager provide APIs to access contacts and phone functions, respectively. Listeners can monitor phone states and incoming calls. SMS and Bluetooth functions also use contexts and intents to communicate between components.

1. Android Programming
Yong Heui Cho @ Mokwon University

2. 2
Context
• Interface to global information about an
application environment
• Uses of context
– Creating new objects
– Accessing standard common resources
– Accessing components implicitly
Activity
Context
OS

3. 3
Access of Context
• this
– Activity extends Context
• View.getContext()
– Context for View (usually Activity Context)
• Activity.getApplicationContext()
– Permanent Application Context
• ContextWrapper.getBaseContext()
– Access to another Context

4. 4
Bundle vs. Parcel
• Bundle
– A mapping from String values to various Parcelable
types
• Parcelable
– Interface for classes whose instances can be written
to and restored from a Parcel
• Parcel
– Container for a message (data and object
references) that can be sent through an IBinder

5. 5
ContactsContract
• Contract between the contacts provider
and applications
• Context.getContentResolver()
• Cursor: interface of results for database
query
Content Provider
Contacts Provider
Activity
Context
OS
getContentResolver()
ContactsContract

6. 6
Telephony Manager
• Access to the telephony APIs is managed by the
Telephony Manager.
– Monitor phone state
– Retrieve incoming phone numbers
– Observe changes to data connections, signal
strength, and network connectivity

7. 7
PhoneStateListner
• Monitors changes in specific telephony
states on the device, including service state,
signal strength, message waiting indicator
(voicemail).
Activity
Context
PhoneStateListener
OS
TelephonyManager
listen()

8. 8
Incoming Phone Calls
• Service
– an application component representing either an application's desire to
perform a longer-running operation while not interacting with the user or
to supply functionality for other applications to use
• IntentFilter
– Structured description of Intent values to be matched
– Context.registerReceiver(BR, IntentFilter)
– Context.unregisterReceiver(BR)
Activity
Context
OS
Service
broadcast
Intent
BroadcastReceiver
brTx
Context
registerReceiver() with IntentFilter

9. 9
Receiving Call
• Permission
– <uses-permission
android:name="android.permission.READ_P
HONE_STATE" />
Activity
Context
OS
Service
Intent
PhoneStateListener
rxListener
Context
TelephonyManager
listen()

10. 10
Sending SMS
• SmsManager
– SmsManager.getDefault().sendTextMessage(phoneNum, null,
msg, piSent, piDelivered);
• PendingIntent
– a description token for a foreign application to allow the foreign
application to use our application's permissions
– Action → Intent → PendingIntent(for broadcast)
Activity
Context
BroadcastReceiver
brSend
OS
SmsManager
broadcast
BroadcastReceiver
brDeliever
registerReceiver() with IntentFilter
PendingIntent

11. 11
Receiving SMS
• Receiving process
– Broadcast → Intent → Bundle → PDU (Object[]) →
SmsMessage → String
• Bundle: a mapping (or dictionary) class from String
key to various types
• PDU: Protocol Description Unit
Activity
Context
BroadcastReceiver
brReceive
OS
SmsManager
Intent via broadcast
registerReceiver() with IntentFilter

12. 12
Bluetooth Setup
• BluetoothAdapter (my device)
• BluetoothDevice (partner devices)
• void onActivityResult(int requestCode, int resultCode,
Intent data)
• Parcelable Intent::getParcelableExtra(String)
Activity
Context
BroadcastReceiver
brBluetooth
My OS
BluetoothAdapter
- getDefaultAdapter()
- isEnabled()
- startDiscovery()
- cancelDiscovery()
Intent via broadcast
registerReceiver() with IntentFilter
BluetoothDevice
- getName()
- getAddress()
Partner OS
Bluetooth