How to show unread messages in list view in android?

i am making a chat application. i want to show unread messages in my activity screen when notification arrived. My activity screen contain list view and i want show unread messages count in particular item in list view. I am using Sqlite database for store message and in table one column is notify_seen. So, i check notify_seen is "0" then count message as "UNREAD" and show unread message count in list view.I am using Custom List view extends BaseAdapter. recently i am running thread on screen and check database for unread message and using adpter notifyDataSetChanged update Ui , but it take too much load on screen.

So if any solution how to show unread messages count please help me.....

Thank you.