package gates.apps.automaticmessageresponder;

import android.app.Activity;
import android.content.ComponentName;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    
    
    public void register(View view){
    	ComponentName receiver = new ComponentName(this, SmsReceiver.class);
    	    PackageManager pm = this.getPackageManager();
    	    pm.setComponentEnabledSetting(receiver,
    	
    	            PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
    	
    	            PackageManager.DONT_KILL_APP);
    	
    	
    }
    public void unRegister(View view){
    	
    	ComponentName receiver = new ComponentName(this, SmsReceiver.class);
    	
    	    PackageManager pm = this.getPackageManager();
    	    pm.setComponentEnabledSetting(receiver,
    	
    	            PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
    	
    	            PackageManager.DONT_KILL_APP);
 	
    }
    
    
   
    @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;
    }
    
}


======= another class ====
package gates.apps.automaticmessageresponder;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.telephony.SmsMessage;
import android.util.Log;
import android.widget.Toast;



public class SmsReceiver extends BroadcastReceiver {

	// Get the object of SmsManager
	final SmsManager sms = SmsManager.getDefault();

	@Override
	public void onReceive(Context context, Intent intent) {
		// TODO Auto-generated method stub
		
		
		// Retrieves a map of extended data from the intent.
		final Bundle bundle = intent.getExtras();
		 
		try {
		     
		    if (bundle != null) {
		         
		        final Object[] pdusObj = (Object[]) bundle.get("pdus");
		         
		        for (int i = 0; i < pdusObj.length; i++) {
		             
		            SmsMessage currentMessage = SmsMessage.createFromPdu((byte[]) pdusObj[i]);
		            String phoneNumber = currentMessage.getDisplayOriginatingAddress();
		             
		            String senderNum = phoneNumber;
		            String message = currentMessage.getDisplayMessageBody();
		 
		            Log.i("SmsReceiver", "senderNum: "+ senderNum + "; message: " + message);
		             
		 
		           // Show alert
		            int duration = Toast.LENGTH_LONG;
		            Toast toast = Toast.makeText(context, "senderNum: "+ senderNum + ", message: " + message, duration);
		            toast.show();
		           
		            
		            
		            
		            
		            
		             
		        } // end for loop
		      } // bundle is null
		 
		} catch (Exception e) {
		    Log.e("SmsReceiver", "Exception smsReceiver" +e);
		     
		}
		
		
		
		
	}
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
}