Changing ViewController if user is Facebook Logged in - ios

Question

I'm having quite some troubles implementing Facebook login in my iOS , everything works fine if the user is not already logged in, the application fetches correctly the data from Facebook and pass them to the next ViewController , instead if is already logged in it should automatically segue to a recap page that shows user's info but i can't make it happen, currently I'm using this method :
override func viewDidLoad() {
super.viewDidLoad()
LoginButton.delegate = self
if (FBSDKAccessToken.currentAccessToken() != nil) {
self.performSegueWithIdentifier("Login", sender: self)
}
}
but in the console i get :
Facebook_Login.LoginViewController: 0x7fc04a519ca0 on Facebook_Login.ViewController: 0x7fc04a41c1e0 whose view is not in the window hierarchy!
i've also tried using the viewdidAppear method, but it segues to the recap page without updating the variables so i get an empty page
here' the complete code:
View Controller 1
import UIKit
import FBSDKLoginKit
class 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:
import UIKit
import FBSDKLoginKit
class 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

First of all, avoid to reset your LoginButton.delegate in the LoginAction() function.
If the user is already logged in, to avoid an useless call to the Facebook Graph API (if you do not necessarily need to update his informations), you can store your user informations in CoreData or in a NSUserDefault.
If you never used it you can use the CDHelper lib (CoreDataHelper) which will allow you to use it without difficulties.
Hope I was helpful, if not, do not hesitate to give us a feedback.
Btw, in your viewDidAppear(animated: Bool) function, you have to call super.viewDidAppear(animated) !