Store UserID From Facebook SDK

问题

How can I store credentials in the Facebook iOS SDK atleast username if not password. I gone through the Facebook iOS SDK ...FBSession which is been need to use login part.but its a Library file ..I cannot see the implementation part .which is

[[FBSession activeSession] openWithBehavior:FBSessionLoginBehaviorForcingWebView

                  completionHandler:^(FBSession *session,

                                      FBSessionState state,

                                      NSError *error) 

Is it possible to keep credentials? or to hacking a UIWebView to load the facebook login page without showing it to the user and inject the credentials if that is possible at all.

来源：https://stackoverflow.com/questions/14323482/store-userid-from-facebook-sdk