How to create a UITextField like MFMailComposer has?

I want to create a MFMailComposer like UITextField like when we type an email address it converted into blue round button 开发者_如何学JAVAlike shape. I do not want to use Three20's MailComposer. I want to create my own.Any idea how to achieve this? or if there is already a UITextField or whatever control is out there please let me know.

EDIT: I've checked three20's TTCatalog demo. And It has all the things I want except a few like when I type an email address manually it's not converted into the blue button.Also I want to send mail using my own methods because I'm doing encryption of message. And I want to get all the email addresses entered in the To field and I want a Cc/Bcc field like MFMailComposer has.

Check out TITokenFieldView - you may be able to use/adapt for your needs