contact change listner

package contact.change.listner;

import android.app.Activity;
import android.database.ContentObserver;
import android.os.Bundle;
import android.provider.Contacts.People;

public class contactchangelistner extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
  
     
            this.getApplicationContext().getContentResolver().registerContentObserver (People.CONTENT_URI, true, contentObserver);
        }

        private class MyContentObserver extends ContentObserver {

            public MyContentObserver() {
                super(null);
            }

            @Override
            public void onChange(boolean selfChange) {
                super.onChange(selfChange);
        
            System.out.println("==========change");
            }

        }

        MyContentObserver contentObserver = new MyContentObserver();
    }

URL:http://stackoverflow.com/questions/1401280/how-to-listen-for-changes-in-contact-database