Broadcast Receivers
Definition:
Broadcast Receiver in Android – is an Android component that responds to system-wide broadcast messages or messages from other applications. It allows an app to listen for things like battery state, network connectivity, SMS receipt/queuing if you’re using the telephony API (not available in SFE), and more.
Introduction
Broadcast Receivers are fundamental building blocks of the Android framework and are instrumental to facilitating communication between applications and the system. They let apps respond to system-level notifications and custom intents without having to have a continually running app. The receivers are lightweight, event-triggered components that get triggered only when the broadcast intent they matched is received.
Explanation
A broadcast is a way for the system or an application to announce certain information to all interested recipients. in Broadcast Receivers: BroadcastReceiver have to subscribe and listen for events( intent actions), when such event occurs a certain method called onReceive() is raised on receiver.
There are 2 ways you may advertise a receiver:
Defining Static Registration – Specified in the AndroidManifest. xml. We’ve found that they even function when the app itself is closed!
Dynamic Registration – Register at runtime with code, typically in services or activities.
There are at most two type of broadcast:
System Broadcasts: Emitted by Android (e.g., BOOT_COMPLETED, BATTERY_LOW).
Application Broadcasts: These are sent from apps to other apps or within the same app.
Features / Characteristics
- Component that runs code only when an event happens.
- No GUI (which makes it light and memory friendly).
- Registered through manifest or programmatic as per your requirement.
- Deals with system and custom broadcasts.
- Instruction is quick as onReceive() executes on the main thread.
May be able to invoke background services or activities when you receives events.
Example
- Example: Listening for Network Connectivity Changes
- Manifest Registration (Static Receiver)
- Broadcast Receiver Class
public class NetworkReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast. makeText(context, “Network state changed!”, Toast. LENGTH_SHORT). show(); } }
Explanation:
When the connection changes (Wi-Fi or mobile), Android broadcasts an Intent with the action CONNECTIVITY_CHANGE. The registered receiver receives this event and calls the code in onReceive().
Advantages / Importance
- Lazy event handling because receivers become active only when they are needed.
Enhances the user experience by reacting to system changes quickly (such as, a low battery warning).
Provides Media Playing Inter-App Communication by custom Broadcast.
Improves app performance without having to keep the components running all the time.
Great for simple periodic tasks (Habit tracking, performing a task daily), serving as an alarm or tracking the state of certain system capabilities.
Conclusion
Broadcast Receivers are indispensable elements of an Android platform and helps in listening to the system-level, global events as well as application specific events. Their lightweight, event-driven behavior is perfect for background logic, triggered messaging and app-to-app intercommunication. They play a major role in building Android applications that are responsive, performant and interactive.