Is there an easy way to know which contact changed while using ContentObserver for android contacts?

Question

I store some contacts in my app and want to know if any one of them is edited by user through the contact app. So I register a contentObserver for this. The 'onChange()' method for the contentObserver doesn't provide anything other than 'selfChange' boolean parameter. So is there any way I can find which contact changed other that looping through every contact and comparing the fields for changes?