A BroadcastReceiver in Android is a component that allows applications to listen for system-wide or app-specific broadcast messages. These messages, or broadcasts, are sent when certain events occur, such as receiving a text message, the device charging, network connectivity changes, or a custom event triggered by an app. The BroadcastReceiver class enables apps to respond to these events even if the app is not currently running in the foreground. Developers can register receivers either statically in the AndroidManifest.xml or dynamically in code using Context.registerReceiver(). When a broadcast is received, the system calls the onReceive() method of the BroadcastReceiver, where the app can perform short tasks like showing a notification or starting a service. However, it should not perform long-running operations directly inside onReceive() to avoid ANR (Application Not Responding) errors. There are two main types of broadcasts: System broadcasts (e.g., BOOT_COMPLETED, BATTERY_LOW) Custom broadcasts defined by apps for inter-component communication. From Android 8.0 (API level 26) onward, background limitations were added, restricting implicit broadcasts for better battery life and performance. Overall, BroadcastReceivers are a powerful tool for building responsive, event-driven Android applications. Learn more on https://flutterjunction.com/notes/android-application-development

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Broadcast Receiver
How Android apps listen to system-wide or app-specific events

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BroadcastReceiver
A BroadcastReceiver is a component that listens and responds to broadcast messages
(Intents) from the system or other apps.
BroadcastReceiver is used when your app needs to react to system-wide or app-wide
events, even when it’s not open or visible.
Purpose
● React to system events (e.g. charging, boot complete)
● Communicate between components
Analogy
Like a radio receiver that listens for specific channels (events)

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Types of Broadcasts
📣 1. System Broadcasts
● Sent by Android OS
● Example: BOOT_COMPLETED, BATTERY_LOW, SMS_RECEIVED
📣 2. Custom Broadcasts
● Sent by your own app or other apps
● Useful for app-to-app or component communication

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Creating a BroadcastReceiver
● Create a class extending BroadcastReceiver
● Override onReceive() method
public class MyReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "Broadcast received!", Toast.LENGTH_SHORT).show();
}
}

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Registering BroadcastReceiver
📍 Static Registration (Manifest)
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
</receiver>

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Registering BroadcastReceiver
📍 Dynamic Registration (in Activity)
MyReceiver receiver = new MyReceiver();
IntentFilter filter = new IntentFilter(Intent.ACTION_AIRPLANE_MODE_CHANGED);
registerReceiver(receiver, filter);
📍 Unregister
unregisterReceiver(receiver);

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Sending Custom Broadcasts
Send a broadcast
Intent intent = new Intent("com.example.MY_CUSTOM_ACTION");
sendBroadcast(intent);
Receive it in your receiver
<action android:name="com.example.MY_CUSTOM_ACTION" />