In order to get the user's email address from Facebook, you have to use the Graph API to query the current user using the Social framework:
SLRequest *request = [SLRequest requestForServiceType:SLServiceTypeFacebook
requestMethod:SLRequestMethodGET
URL:[NSURL URLWithString:@"https://graph.facebook.com/me"]
parameters:nil];
request.account = _account; // This is the _account from your code
[request performRequestWithHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
if (error == nil && ((NSHTTPURLResponse *)response).statusCode == 200) {
NSError *deserializationError;
NSDictionary *userData = [NSJSONSerialization JSONObjectWithData:data options:0 error:&deserializationError];
if (userData != nil && deserializationError == nil) {
NSString *email = userData[@"email"];
NSLog(@"%@", email);
}
}
}];