BroadCast Receiver

Broadcast Receiver - To listen the system as well as custom intent.

Android OS is firing multiple intents like - SYSTEM_REBOOT, BATTERY_LOW/HIGH,  NETWORK STATUS and so on.

Intent - It is a messaging object which is used to pass the message from one component to another.

1. Create BroadcastReceiver Class

public class BReceiver  extends BroadcastReceiver

2. Register and Filter Intent - Register Broadcast Receiver class to listen to System intent.
and by using IntentFilter we specify which intent app listens.

2.1 Register receiver  in Android Manifest

<receiver android:name=".BReceiver">
    <intent-filter>
        <action android:name="divakar"></action>
    </intent-filter>
</receiver>

2.2 Register receiver programmatically.

final BReceiver bReceiver = new BReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("divakar");
registerReceiver(bReceiver, filter);

if you want to send broadcast localy(within app)

LocalBroadcastManager.getInstance(this).registerReceiver(bReceiver, filter);

3. Receive data

    @Override    public void onReceive(Context context, Intent intent) {

        if (intent.getAction() == Manifest.permission.CHANGE_WIFI_STATE) {
            
        }
    }

4. Send Custom Intent

Intent i = new Intent();
i.setAction("divakar");
i.putExtra("key", "divakar-main-data");
sendBroadcast(i, Manifest.permission.CHANGE_WIFI_STATE);

5. Receive Custom Intent

    @Override    public void onReceive(Context context, Intent intent) {

        if (intent.getAction().equalsIgnoreCase("divakar")) {
            String s = intent.getExtras().getString("key");
            Toast.makeText(context, "Broadcast Receiver called : "+s, Toast.LENGTH_LONG).show();
        }else {
            Toast.makeText(context, "Something changed", Toast.LENGTH_LONG).show();
        }
    }