如何检查用户是否用iOS的FBSDKLoginKitlogin？

当我在viewDidLoad运行应用程序时，我需要检查用户是否曾经login过。

 if FBSDKAccessToken.currentAccessToken() != nil { print("1") presentViewController(controller, animated: true, completion: nil) } else { print("2") let button = FBSDKLoginButton() button.delegate = self button.readPermissions = ["public_profile", "user_friends"] view.addSubview(button) } 

它总是打印"2" 。 为什么？

Answer 1

下面两个方法必须在AppDelegate实现：

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions) } func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject) -> Bool { return FBSDKApplicationDelegate.sharedInstance().application(application, openURL: url, sourceApplication: sourceApplication, annotation: annotation) }