Facebook SDK iOS invite user without FBWebDialogs

Question

I want to get list of my friends from Facebook who are not users of my app, and be able to invite them.

Using FBWebDialogs I can pick users, but I'm wondering how foursquare did it? Screenshot:

Answer 1

There is option of frictionless requests.
On Facebook developer site they mentioned in section of Invites and Requests

We touched on a scenario where users exchange requests back and forth. If this scenario is typical in your game, it can be a bad user experience to force them through the request dialog every time they want to send a request. The solution for this is frictionless requests.

Frictionless requests let users send requests to friends from an app without having to click on a pop-up confirmation dialog. When sending a request to a friend, a user can authorize the app to send subsequent requests to the same friend without another dialog. This streamlines the process of sharing with friends.

For more reference see Facebook Invites and Requests