Simple Example of using LocalBroadcastManager in Android

LocalBroadcastExampleActivity.java

import android.app.Activity;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class LocalBroadcastExampleActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.log_list);
		
		Button buttonStartService = (Button)findViewById(R.id.button_ok);
		buttonStartService.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				//Register MessageService in Manifest to work
				startService(new Intent(LocalBroadcastExampleActivity.this, MessageService.class));
			}
		});

	}

	@Override
	protected void onPause() {
		// Unregister since the activity is paused.
		LocalBroadcastManager.getInstance(this).unregisterReceiver(
				mMessageReceiver);
		super.onPause();
	}

	@Override
	protected void onResume() {
		// Register to receive messages.
		// We are registering an observer (mMessageReceiver) to receive Intents
		// with actions named "custom-event-name".
		LocalBroadcastManager.getInstance(this).registerReceiver(
				mMessageReceiver, new IntentFilter("custom-event-name"));
		super.onResume();
	}

	// Our handler for received Intents. This will be called whenever an Intent
	// with an action named "custom-event-name" is broadcasted.
	private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
		@Override
		public void onReceive(Context context, Intent intent) {
			// TODO Auto-generated method stub
			// Get extra data included in the Intent
			String message = intent.getStringExtra("message");
			Log.d("receiver", "Got message: " + message);
		}
	};

	public class MessageService extends Service {

		@Override
		public IBinder onBind(Intent intent) {
			// TODO Auto-generated method stub
			return null;
		}

		@Override
		public int onStartCommand(Intent intent, int flags, int startId) {
			// TODO Auto-generated method stub
			sendMessage();
			return super.onStartCommand(intent, flags, startId);
		}
		
		// Send an Intent with an action named "custom-event-name". The Intent
		// sent should
		// be received by the ReceiverActivity.
		private void sendMessage() {
			Log.d("sender", "Broadcasting message");
			Intent intent = new Intent("custom-event-name");
			// You can also include some extra data.
			intent.putExtra("message", "This is my message!");
			LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
		}

	}

}

Thanks for sharing!

The code here Has no sense.

How you send local broadcast from service if your service class not embedded in Activity?

LocalBroadcastManager.getInstance(this) - would not work, because "this" is Activity context

I stuck on this problem when tried to send local broadcast from non UI thread

@samboy51 android service has its own context here, you must be calling this from some other class

Do you have an example of the manifest ?

I tried

            <service
                android:name=".MessageService"
                android:exported="false" />

But it doesn't seems to work.

Thanks for sharing, I was registering the broadcast receiver at onCreate, it was stacking receivers...

Thanks.for this piece

Perfect one to understand the concept...

The biggest problem with these receivers is that if you want to receive the broadcast when your activity is Paused or in Background, then you cant do that in a clean way. You have to unregister the receiver in onDestroy not onPause so broadcast can be received when the activity is in the background. Sure, there are ways like using AsyncTask for such things or ForegroundService but it would be nice to have such a functionality for BroadcastReceivers so that you wont have to set up certain parts of the app differently.

the above code didnot run for me asswell but it was helpful
here is what i did to make it run below is full tutrial

mainactivity
`package com.javacodegeeks.android.androidserviceexample;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.IntentFilter;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {
private IntentFilter receiveFilter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    receiveFilter = new IntentFilter("custom-event-name");
    LocalBroadcastManager.getInstance(this).
            registerReceiver(handler, receiveFilter);

}

// Start the  service
public void startNewService(View view) {
    Intent intent=new Intent(this,MyService.class);
    intent.putExtra("string","string_value");
    this.startService(intent);
}

// Stop the  service
public void stopNewService(View view) {

    stopService(new Intent(this, MyService.class));
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

private BroadcastReceiver handler = new BroadcastReceiver() {

    int i =0 ;
    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d("TAGS", "BroadcastReceiver() {...}.onReceive()");
        Log.d("TAGS", String.valueOf(i));
        i=i+1;
        Toast.makeText(MainActivity.this,
                "Message received", Toast.LENGTH_LONG).show();



    }
`};`

}

`Myservice.java
package com.javacodegeeks.android.androidserviceexample;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.widget.Toast;

public class MyService extends Service {
public MyService() {
}

@Override
public IBinder onBind(Intent intent) {
    // TODO: Return the communication channel to the service.
    throw new UnsupportedOperationException("Not yet implemented");
}



@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    if (intent !=null){
        Log.d("TAGS_service_data", String.valueOf(intent.getExtras().getString("string")));

    }

    Toast.makeText(this, " Service Started", Toast.LENGTH_LONG).show();

    Log.d("TAGS", "MainActivity.send()");
    //Intent sendableIntent = new Intent(getClass().getName());
    Intent sendableIntent = new Intent("custom-event-name");

    sendableIntent.putExtra("result", "risult");

    LocalBroadcastManager.getInstance(this).
            sendBroadcast(sendableIntent);
    Log.d("TAGS", "sended_data");


    return Service.START_STICKY;

}

@Override
public void onCreate() {
    Toast.makeText(this, "The new Service was Created", Toast.LENGTH_LONG).show();

}

/* @OverRide
public void onStart(Intent intent, int startId) {
// For time consuming an long tasks you can launch a new thread here...
Toast.makeText(this, " Service Started", Toast.LENGTH_LONG).show();

    Log.d("TAGS", "MainActivity.send()");
    //Intent sendableIntent = new Intent(getClass().getName());
    Intent sendableIntent = new Intent("custom-event-name");

    sendableIntent.putExtra("result", "risult");

    LocalBroadcastManager.getInstance(this).
            sendBroadcast(sendableIntent);
    Log.d("TAGS", "sended_data");


}*/

@Override
public void onDestroy() {
    Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();

}

}`

android manifest.xml
add the service name under the application tag

Better to call super.onPause(); and super.onResume(); at the beginning of method. According this.

@dnadeau-quatral MessageService is inside Activity. Write the code for MessageService in separate file, do the manifest entry and then it will work properly.

@Antarix Thanks.

Simple and to the point thanks ! 😃

Thanks

This is the most self descriptive straight to the core demo.

@dnadeau-quatral it should be ".LocalBroadcastExampleActivity$MessageService" , just type . and it will suggest ".LocalBroadcastExampleActivity$MessageService"

Nice work, thanks.

Thank you

Thanks! I searched a reason why not working many hours. LocalBroadcastManager.getInstance(this).registerReceiver() - this is an answer! )))