Android Broadcast Receivers

1. Overview 

Now friends we are going to learn about  Broadcast Receivers
Broadcast Receivers is an android componant which response to broadcast messages from an applications or system itself.Broadcast Receivers will catch specific event from android oprating system, this is happen when wifi on,battery status change,recieved phone calls and cut etc.we can also send Broadcast messages throw intent with the help of "sendBroadcast(intent object)" methos.

there are two way to create Broadcast Receiver

1) static type - registered receiver at AndroidManifest.xml file
2) dynamic type -  registered receiver at dynamically with the help of registered() or unregisterReceiver() methods

2.. How to registered receiver at AndroidManifest.xml file

MyReceiver is a name of Broadcast Receiver

<receiver android:name="MyReceiver">

       <intent-filter>

          <action android:name="com.hello.app"/>

          <category android:name="android.intent.category.DEFAULT"/>

       </intent-filter>

</receiver>

3. Create activity_main.xml layout

In this layout we will take two componant first EditText and second Button.we wiil get some text from EditText and after click on Button send broadcast message

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

     xmlns:tools="http://schemas.android.com/tools"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:paddingBottom="@dimen/activity_vertical_margin"

     android:paddingLeft="@dimen/activity_horizontal_margin"

     android:paddingRight="@dimen/activity_horizontal_margin"

     android:paddingTop="@dimen/activity_vertical_margin"

     tools:context=".MainActivity" >

   <EditText

      android:id="@+id/editText1"

      android:layout_width="wrap_content"

      android:layout_height="wrap_content"

      android:layout_alignParentLeft="true"

      android:layout_alignParentTop="true"

      android:layout_marginLeft="44dp"

      android:layout_marginTop="26dp"

      android:ems="10" >

    <requestFocus />

  </EditText>

  <Button 

   android:id="@+id/button1"

   android:layout_width="wrap_content"

   android:layout_height="wrap_content"

   android:layout_alignLeft="@+id/editText1"

   android:layout_below="@+id/editText1"

   android:layout_marginTop="32dp"

   android:text="Send Signal" />

</RelativeLayout>

4.How to create  Broadcast  sender

send Broadcast message by sendBriadcast method

package com.example.broadcastsenderapp;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends Activity {

EditText et;

Button bt;

@Override

protected void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

           setContentView(R.layout.activity_main);

          et = (EditText) findViewById(R.id.editText1);

          bt = (Button) findViewById(R.id.button1);

       bt.setOnClickListener(new OnClickListener()

       {

            @Override

            public void onClick(View v)

            {

                   String data = et.getText().toString();

                   Intent in = new Intent("com.hello.app");

                   in.putExtra("data",data);

                   sendBroadcast(in);

            }

       });

    }

    @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;

       }
  }

3.Create Broadcast Receiver

here  receive message by intent

package com.example.broadcastsenderapp;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.widget.Toast;

public class MyReceiver extends BroadcastReceiver{

    @Override

    public void onReceive(Context arg0, Intent in)

   {

        String data = in.getStringExtra("data");

        Toast.makeText(arg0, data, 2).show();

    }
}

if you have any issue and want to know more about Broadcast receiver please comments on blow comments box.

Thanks..