在视图控制器之间传递 FBSDK 登录管理器结果

Posted 2023-03-17

【中文标题】在视图控制器之间传递 FBSDK 登录管理器结果

【英文标题】：Passing FBSDK login manager result between view controllers

【发布时间】：2017-05-19 10:11:21

【问题描述】：

我无法在视图控制器之间传输登录管理器结果， segue 与按钮相关联，其标识符为 s1。 我的设置是正确的。程序因绿色断点而崩溃。 这是我的代码： 对于第一个 VC：

import FBSDKLoginKit


class ViewController: UIViewController 

    var user_name: String?

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    


    override func prepare(for segue: UIStoryboardSegue, sender: Any?) 
        let fbLoginManager = FBSDKLoginManager()
        fbLoginManager.logIn(withReadPermissions: ["public_profile", "email"], from: self)  (result, error) in
            if let error = error 
                print("Failed to login: \(error.localizedDescription)")
                return
            

            guard let accessToken = FBSDKAccessToken.current() else 
                print("Failed to get access token")
                return
            

            let credential = FIRFacebookAuthProvider.credential(withAccessToken: accessToken.tokenString)


            FBSDKGraphRequest(graphpath: "/me", parameters: ["fields" : "email, id, locale"])
                .start(completionHandler:   (connection, result, error) in
                    guard let result = result as? NSDictionary,
                        let user_name = result["user_name"] as? String,

                        else 

                            return
                    

                    if(segue.identifier == "s1")
                        if let v = segue.destination as? Re 


                            v.uname=user_name ?? ""



                            //v.uname = usr.text ?? ""
                        
                                  


                )


            // Perform login by calling Firebase APIs
            FIRAuth.auth()?.signIn(with: credential, completion:  (user, error) in
                if let error = error 
                    print("Login error: \(error.localizedDescription)")
                    let alertController = UIAlertController(title: "Login Error", message: error.localizedDescription, preferredStyle: .alert)

                    return
                



            )

    


    

对于 Re，下一个 VC：

class Re: UIViewController 
    var uname: String?    
    @IBOutlet weak var l1: UILabel!
    var userfb: String?
    override func viewDidLoad() 
        super.viewDidLoad()
l1.text=uname
        // Do any additional setup after loading the view.
    

【参考方案1】：

您需要使用您在顶部声明的实例变量，如下所示。 现在你已经创建了新的user_name 并使用了另一个user_name

guard let result = result as? NSDictionary,
                        user_name = result["user_name"] as? String,// make change here

                        else 

                            return
                    

【讨论】：

NSDictionary 类型的值未解包，您是要使用吗？或！

这是您的代码。我刚刚删除了局部变量并使用了您的全局变量。我

程序仍然崩溃。I.只是想在视图控制器之间传递 Facebook 登录管理器结果。我已经阅读了很多类似的代码来做到这一点