Can't get Facebook data fast enough - ios

Question

I'm trying to get Facebook's user name and photo in my code. I'm able to do both, but the problem is the segue is called before the data return to me! So when I go to the next screen, the variables are nil! Here is my code:
override func viewDidLoad() {
super.viewDidLoad()
//MARK: - FB Button customization:
if (FBSDKAccessToken.currentAccessToken() == nil){
print("Not logged in")
}
else{
print("This is where you perform a segue.")
fetchProfile()
performSegueWithIdentifier("nextfb", sender: self)
}
}
func fetchProfile() {
print("fetch profile")
let parameters = ["fields": "email, name, picture.type(large)"]
FBSDKGraphRequest(graphPath: "me", parameters: parameters).startWithCompletionHandler { (connection, result, error) -> Void in
if error != nil {
print(error)
return
}
if let name = result["name"] as? String {
self.nome = name
print(name)
print(self.nome)
}
if let email = result["email"] as? String {
self.email = email
print(email)
}
// pega a imagem do usuário:
if let data = result["picture"]?!["data"]
{
if let url = data!["url"] as? String
{
let profilePictureURL = url
let imgURL = NSURL(string: profilePictureURL)
let imageData = NSData(contentsOfURL: imgURL!)
let image = UIImage(data: imageData!)
print(image)
self.foto = image!
}
}
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "nextfb" {
print("\nO NOME É: \(nome)\n")
let vc = segue.destinationViewController as! HomeViewController
vc.name = self.nome
//vc.photo = self.foto
}
}
The second View Controller prints a nil value for the name AND THEN the first View Controller prints the name and the image! (when I'm already in the second View Controller)
How can I pass those variables via segue properly?? Any help is much appreciated!

Answer 1

You are calling performSegueWithIdentifier("nextfb", sender: self) in the wrong place. You are checking the existence of your access token, and if you aren't logged in, you are invoking the segue.
Instead of that, you should do this:
if let data = result["picture"]?!["data"]
{
if let url = data!["url"] as? String
{
let profilePictureURL = url
let imgURL = NSURL(string: profilePictureURL)
let imageData = NSData(contentsOfURL: imgURL!)
let image = UIImage(data: imageData!)
print(image)
self.foto = image!
performSegueWithIdentifier("nextfb", sender: self)
}
}
This way you only go to the next controller when your data has successfully populated on your view controller.