No FBSession in Facebook iOS SDK 4.x
Vincent is right, check [FBSDKAccessToken currentAccessToken] to determine if the user is logged in.
To check if the user logged in and if so, navigate to another view:
if ([FBSDKAccessToken currentAccessToken]) { // User is logged in [self performSelector:@selector(accessGrantedNavigation) withObject:nil afterDelay:0.0];}-(void)accessGrantedNavigation{ [self performSegueWithIdentifier: @"segueLoginFB" sender: self];}To log out: (although it doesn't allow to change FB user. I think it is because Safari already takes care of that session and remains the same user.)
FBSDKLoginManager *manager = [[FBSDKLoginManager alloc] init]; [manager logOut];Hope it helps.