1 / 16

Android ICC Part II

Android ICC Part II. Inter-component communication. Broadcast Receivers. BRs are app components that receive intents sent from the system and/or other apps A BR has to register with the Activity Manager and Package Manager Registration can be done through the The manifest file

ince
Download Presentation

Android ICC Part II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Android ICC Part II Inter-component communication

  2. Broadcast Receivers • BRs are app components that receive intents sent from the system and/or other apps • A BR has to register with the Activity Manager and Package Manager • Registration can be done through the • The manifest file • Programmatically

  3. BR registration within Manifest <receiver android:name=''MsgListener'' > <intent-filter> <action android:name=''pacman.intent.action.BROADCAST'' /> </intent-filter> </receiver>

  4. BR registration within Manifest <receiver android:name=''MsgListener'' > <intent-filter> <action android:name=''pacman.intent.action.BROADCAST'' /> </intent-filter> </receiver> Class responsible for processing the Intent Filter to specify what intents to receive

  5. BR program. registration IntentFilter filter = new IntentFilter(); filter.addAction(``pacman.intent.action.BROADCAST’’); receiver = new BroadcastReceiver() f //@Override public void onReceive(Context context, Intent intent) { System.out.println(``message receivednn''); } }; registerReceiver(receiver, filter);

  6. BR program. registration Filter to specify what intents to receive IntentFilter filter = new IntentFilter(); filter.addAction(``pacman.intent.action.BROADCAST’’); receiver = new BroadcastReceiver() f //@Override public void onReceive(Context context, Intent intent) { System.out.println(``message receivednn''); } }; registerReceiver(receiver, filter); Action performed when the intent is received Registration of the BR and filter

  7. Registering Broadcast Receivers • When BRs are registered programmatically generate REGISTER_RECEIVER_TRANSACTION ioctl to AM via Binder • Registration through manifest does not generate any transactions

  8. Broadcasting Intents • To broadcast an intent the sendBroadcast API should be used • Generates a BROADCAST_INTENT_TRANSACTION ioctl to AM through the Binder Intent intent = new Intent(``pacman.intent.action.BROADCAST''); intent.putExtra(``message'',''Wake up.''); sendBroadcast(intent);

  9. Content Providers • CPs are the components in an app responsible for storing data • CPs must be declared in the manifest file using the <provider> tag • CPs are accessed by URI: • content://<authority>/<resource>

  10. Content Providers • Access to a CP is handled by the AM • Ioctlwith GET_CONTENT_PROVIDER_TRANSACTION • Specifying the authority • The AM finds the suitable CP and sends back a handler to communicate directly with the CP • Then the app can send URI along with the requested operations: • QUERY_T, GET_TYPE_T, INSERT_T, DELETE_T, UPDATE_T, BULK_INSERT_T, OPEN_FILE_T, OPEN_ASSET_FILE_T

  11. Service Manager • The Service Manager is a special system service to keep track of the services available in a device • An app that wants to provider a service to others can publish its service through the SM • Communication to SM is done through Binder

  12. Service Manager Commands • The SM accepts the following commands: • publish: takes two arguments – service name and address. This is used for publishing a service within the SM • get/check: take one argument – service name. The SM returns a address of the service in the form of a handler • list: this lists the service names registered with the SM

  13. Service Manager in Action

  14. Service Manager ioctl ioctl on /dev/binder with BINDER_WRITE_READ cmd:BC_TRANSACTION: target name = android.os.IServiceManager code = SVC_MGR_GET_SERVICE service name = isms

  15. Final Thoughts • Android ICC is both very powerful and flexible • High-level API for dynamic interaction between apps • Discovery of functionality on the fly • If not protected properly it can lead to serious consequences

  16. Questions?

More Related