Two way sync adapter in Android

I have gone through a number of links and have spend a huge amount of time over this. Can someone please let me know the simplest approach to implement the Syn开发者_开发百科c Adapter in Android which is 2 way. I mean the changes made on the remote database get reflected on the Android Device and the changes from the device should get updated on the server too.

Also, how to edit the contacts from the default contacts app editor??