I am developing an App which has a search functionality for user's emails with Gmail Account, But I don't know exactly how to integrate Gmail account into my app and get the list of all emails. And Please let me know if any Search API is available of Gmail for iOS?
You may want to look into this website because there is no API from Google to get you're emails. You need to do this through the POP protocol.
http://www.example-code.com/objc/pop3_gmail.asp
then see the features here for the library http://www.chilkatsoft.com/email-features.asp
and download the library here http://www.chilkatsoft.com/downloads_objc.asp
Hope this will get you started with reading emails and listing them, good luck!
as and addition have a look into: https://github.com/mronge/mailcore
and another addition: http://www.etpan.org/
Interesting too: http://code.google.com/p/remail-iphone/
来源：https://stackoverflow.com/questions/11428077/ios-can-anyone-suggest-me-how-can-i-integrate-gmail-account-into-my-app-and-ge