In my application I want to fetch my gmail contacts. In my app I have already integrated "Google+ API" So i just need to know that can i access my gmail contact by using the same API. Or I need to integrate Gmail API. Please help me I am new to this
I wouldn't imagine how you would get the contacts from one service by using another? Not everyone in your gmail contacts is going to be on your google+ account, so how would it be possible to get them?
There are other ways and it is documented online how to integrate with gmail, I suggest you research links like the following to find something you need:
It is possible, but only if you ask for the contacts scope alongside your Google+ scopes.
Where you integrate the Google+ API, you will also need to ask for scope https://www.google.com/m8/feeds.
See https://developers.google.com/google-apps/contacts/v3/ for more details.
来源：https://stackoverflow.com/questions/21276606/using-google-plus-api-is-it-possible-to-fetch-gmail-contacts