How to check that which PFUsers are currently using my iOS application or logged-In status?

I am developing a iOS base Chat Application, where i want to Display the current online/offline status of my application user. For database i am using parse.com where all chat records and User details are stored.

Solution

You can add a boolean column (PFUser Class) where it changes to TRUE when the user opens the app, and changes to FALSE when the app is closed (or in background)