如何使用 Graph API 确定用户是否已从 Facebook iOS 注销?

How to find out if user has logged out from Facebook iOS using Graph API?

self.logInButton = FBSDKLoginButton()
self.logInButton.loginBehavior = FBSDKLoginBehavior.Native 
//Above Uses Facebook iOS setting
//login if User is logged in from their device setting

if FBSDKAccessToken.currentAccessToken() == nil{ 
    //User is not logged in
} else { 
    //User is logged in
}

如果发生任何这些情况,我需要找到一种方法。我想知道 Facebook SDK 是否注册了某种通知以了解登录状态是否已更改。

如果有人从 Facebook 注销而不是从我的应用程序注销,FBSDKLoginButtonDelegate 会触发 "loginButtonDidLogOut" 吗?

是的。使用 Facebook 登录委托方法。

这是 Objective-C 但方法调用应该类似: - (void) loginButtonDidLogOut:(FBSDKLoginButton *)loginButton;

https://developers.facebook.com/docs/reference/ios/current/protocol/FBSDKLoginButtonDelegate