Embed contact like iPhone SMS app

I want to create the "add user" functionality as it is available in the messaging app, where when the user starts typing a username, the app looks for a matching user and shows them in a circle, as shown in the screenshot below.

Is this such built-in functionality? If so, what is it called? I would also like to know how to implement a panel containing usernames, especially the fact that when editing the panel is automatically sorted to show all users (in case of sending sms to multiple recipients) and when the focus is off bar it just shows: "To: John Doe recipient 2 and 5 more "

Thanks in advance for your help!

PS can't include screenshot as image because I'm a new user, but here's the url: Create SMS View