Question

我在iOS中实施Facebook登录时遇到了一些麻烦，如果用户尚未登录，一切正常，应用程序正确地从Facebook获取数据并将其传递给下一个ViewController，如果是已登录的应自动转到显示用户信息的回顾页面，但我无法实现，目前我正在使用此方法：

override func viewDidLoad() {
        super.viewDidLoad()

        LoginButton.delegate = self

        if (FBSDKAccessToken.currentAccessToken() != nil) {

            self.performSegueWithIdentifier("Login", sender: self)
        }
    }

但在控制台我得到：

Facebook_Login.LoginViewController：Facebook_Login.ViewController上的0x7fc04a519ca0：0x7fc04a41c1e0，其视图不在窗口层次结构中！

我也尝试过使用viewdidAppear方法，但是它会在不更新变量的情况下进入回顾页面，因此我得到一个空页

这里＆＃39;完整的代码：

查看控制器1

导入UIKit 导入FBSDKLoginKit

类ViewController：UIViewController，FBSDKLoginButtonDelegate {

var nome1:String = ""
var cognome1:String = ""
var email1:String = ""
var compleanno:String = ""
var città:String = ""
var genere:String = ""
var immagine_url:String = ""

@IBOutlet weak var LoginButton: FBSDKLoginButton!

@IBAction func LoginAction(sender: AnyObject) {
    LoginButton.delegate = self
    LoginButton.readPermissions = ["email"]


}

func FetchInfo(){

    print("scarico le informazioni...")

    let parametri = ["fields":"email, first_name, last_name, birthday, hometown, gender, picture.type(large)"]

    FBSDKGraphRequest(graphPath: "me", parameters: parametri).startWithCompletionHandler{(connection,result,error) -> Void in

        if (error != nil){

            print ("errore")
            return
        }

        else {

            if let email = result["email"] as? String {

                print(email)
                self.email1 = email
            }

            if let nome = result["first_name"] as? String {

                print(nome)
                self.nome1 = nome
            }

            if let cognome = result["last_name"] as? String {

                print(cognome)
                self.cognome1 = cognome
            }

            if let compleanno = result["birthday"] as? String{

                print(compleanno)
            }

            if let città = result["hometown"] as? String{

                print(città)
            }

            if var genere = result["gender"] as? String{

                if (genere == "male"){

                    genere = "maschio" 
                }

                else {

                    genere = "femmina"
                }

                print(genere)
            }
        }

        if let picture = result["picture"] as? NSDictionary, data = picture["data"] as? NSDictionary, url = data["url"] as? String{

            self.immagine_url = url
            print(self.immagine_url)


        }

    }

    return
}


func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!){

    if (result.isCancelled == true){
        print("cancellato")
    }

    else {

        print("login effettuato")
        FetchInfo()
        self.performSegueWithIdentifier("Login", sender: self)
    }

}

func loginButtonDidLogOut(loginButton: FBSDKLoginButton!){

}

func loginButtonWillLogin(loginButton: FBSDKLoginButton!) -> Bool{

    return true
}



@IBAction func returned(segue:UIStoryboardSegue){

}



override func viewDidLoad() {
    super.viewDidLoad()

    LoginButton.delegate = self

}

override func viewDidAppear(animated: Bool) {

    if (FBSDKAccessToken.currentAccessToken() != nil) {

        FetchInfo()
        if(nome1 == ""){


                        }

        else {
            self.performSegueWithIdentifier("Login", sender: self)
        }
    }


}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    let destinazione:LoginViewController = segue.destinationViewController
    as! LoginViewController

    destinazione.temp_nome = nome1
    destinazione.temp_cognome = cognome1
    destinazione.temp_email = email1
    destinazione.img_profile_url = immagine_url


}

}

ViewController 2：

导入UIKit 导入FBSDKLoginKit

类LoginViewController：UIViewController，FBSDKLoginButtonDelegate {

var temp_nome = ""
var temp_cognome = ""
var temp_email = ""
var img_profile_url:String = ""


@IBOutlet weak var Nome_Utente: UILabel!

@IBOutlet weak var email: UILabel!

@IBOutlet weak var Immagine_Utente: UIImageView!

@IBOutlet weak var Login_button: FBSDKLoginButton!

@IBAction func Login_button_Action(sender: AnyObject) {

    Login_button.delegate = self
}


func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!){

}

func loginButtonDidLogOut(loginButton: FBSDKLoginButton!){

    self.performSegueWithIdentifier("Back", sender: self)
}


override func viewDidLoad() {
    super.viewDidLoad()

    Nome_Utente.text = "\(temp_nome)" + " " + "\(temp_cognome)"
    email.text = "\(temp_email)"


}



override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

Answer 1

首先，请避免重置LoginButton.delegate功能中的LoginAction()。

如果用户已经登录，为了避免对Facebook Graph API的无用调用（如果您不一定需要更新他的信息），您可以将您的用户信息存储在 CoreData 或在 NSUserDefault 。

如果您从未使用它，可以使用CDHelper lib（CoreDataHelper），这样您就可以毫无困难地使用它。

希望我有所帮助，如果没有，请不要犹豫，给我们一个反馈。

顺便说一句，在您的viewDidAppear(animated: Bool)函数中，您必须致电super.viewDidAppear(animated)！

如果用户登录Facebook，则更改ViewController

1 个答案: