FBSession

FB SDK 3.5 在登入之後一定要做 [FBSession setActiveSession:appDelegate.session];
因為SDK中很多method都會直接呼叫activeSession

[appDelegate.session openWithCompletionHandler:^(FBSession *session,                                                         FBSessionState status,                                                         NSError *error) {
       
        if (!error) {
            if ([appDelegate.session.permissions indexOfObject:@"publish_actions"] == NSNotFound) {
                [appDelegate.session requestNewPublishPermissions:@[@"publish_actions",@"photo_upload"]
                                                  defaultAudience:FBSessionDefaultAudienceFriends
                                                completionHandler:^(FBSession *session,
                                                                    NSError *error) {
                                                    // Handle new permissions callback
                                                    appDelegate.session = session;

                                                    [FBSession setActiveSession:appDelegate.session];
                                                }];
                [self updateView];//為何logout的時候也會跑一次這裡！！？？
            }
        }
       
       
    }];