Android - Broadcast Receiver
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This document discusses BroadcastReceivers in Android. BroadcastReceivers allow apps to register to receive intents or system broadcasts. They can be used to listen for system events like low battery or receive broadcasts from other apps. BroadcastReceivers are registered either dynamically in code or statically in the AndroidManifest file. Broadcasts can be sent using sendBroadcast or sendOrderedBroadcast methods. Ordered broadcasts are executed in a defined order while normal broadcasts run asynchronously. The BroadcastReceiver lifecycle only lasts as long as the onReceive method so asynchronous operations require starting a service.
![Android –
BroadcastReceiver
Yong Heui Cho @ Mokwon University
Some of slides are referred to:
[1] Everything of Android, slideshare.](https://image.slidesharecdn.com/6-151015024415-lva1-app6891/85/Android-Broadcast-Receiver-1-320.jpg)
Android - Broadcast Receiver
- 1. Android – BroadcastReceiver Yong Heui Cho @ Mokwon University Some of slides are referred to: [1] Everything of Android, slideshare.
- 2. 2 Smart Device Structure 4. Android – Application Framework 5. Android – Message 6. Android – BroadcastReceiver 7. Android – Phone Calls
- 3. 3 Broadcast Receiver • An Intent-based publish- subscribe mechanism. • Great for listening system events such as SMS messages. □ Courtesy to Everything of Android, slideshare.
- 4. 4 Uses of BR • A broadcast receiver is a component that does nothing but receive and react to broadcast announcements • Your app can – Receive and react to system services (example: battery low) – Receive and react to other apps broadcast announcements – Initiate broadcasts to other apps □ Courtesy to Everything of Android, slideshare.
- 5. 5 Register of BR • To register Broadcast Receiver, you can – Dynamically register with registerReceiver (in code) – Using <register> tag in AndroidManifest.xml □ Courtesy to Everything of Android, slideshare.
- 6. 6 Send of Broadcast • Broadcast is sent using Intent and sendBroadcast or sendOrderedBroadcast methods • Example: – Intent intent = new Intent(“com.enlume.MSG_PRO"); sendBroadcast(intent); □ Courtesy to Everything of Android, slideshare.
- 7. 7 Normal vs. Ordered • Normal Broadcasts – Sent with sendBroadcast. All broadcasts are run in undefined order, often at the same time. • Ordered Broadcasts – Sent with sendOrderedBroadcast. Each receiver executes in turn. Possible to propagate a result to next receiver. Order can be controlled using android:priority tag. □ Courtesy to Everything of Android, slideshare.
- 8. 8 BR Lifecycle • Broadcast Receiver object is valid only for the duration of the onReceive(Context, Intent) method. – You cannot do anything asynchronous in here! – Except you can start a service, which can start a thread. □ Courtesy to Everything of Android, slideshare.
- 9. 9 BR vs. Listener type BroadcastReceiver Listener goal class for Intents class or interface for Intents & others message mostly global messages mostly specific messages period discontinuous reception frequent (or continuous) reception construction static (manifest) or dynamic dynamic only