How to register listening for Contact changes on android 2.0?

How to register a content observer to listen for changes in the contact database in android开发者_StackOverflow 2.0? What URI should I use?

Thank you

ContactsContract.Contacts.CONTENT_URI

For Example:

mContactsObserver = new ContactsObserver(mHandler);
getContentResolver().registerContentObserver(ContactsContract.Contacts.CONTENT_URI, true, mContactsObserver);

Source: http://developer.android.com/resources/articles/contacts.html