iOS Swift : Facebook Login Error

Question

I am trying to log into an application I am working on using Facebook, but I get an error.
If I have my Facebook account set up in Settings, I get error The operation couldn't be completed. com.facebook.sdk:SystemLoginError The operation couldn't be completed. com.facebook.sdk:SystemLoginError .
If I try to log into without having the Facebook account set up in Settings Screen, I can, because it sends me to Web in order to enter my credentials and allow the application to access my public profile and email address.
How can I solve this problem ?
Thanks !

Answer 1

try facebook login code :

Appdelegate.swift

import UIKit

import FBSDKCoreKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
    }
    func applicationWillResignActive(application: UIApplication) {    
        FBSDKAppEvents.activateApp()
    }
    func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject?) -> Bool {
        return FBSDKApplicationDelegate.sharedInstance().application(application, openURL: url, sourceApplication: sourceApplication, annotation: annotation)
    }
}

ViewController.swift

import UIKit
import FBSDKLoginKit

class ViewController: UIViewController {

    var dict : NSDictionary!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    @IBAction func btnFBLoginPressed(sender: AnyObject) {
        var fbLoginManager : FBSDKLoginManager = FBSDKLoginManager()
        fbLoginManager .logInWithReadPermissions(["email"], handler: { (result, error) -> Void in
            if (error == nil){
                var fbloginresult : FBSDKLoginManagerLoginResult = result
                if(fbloginresult.grantedPermissions.containsObject("email"))
                {
                    self.getFBUserData()
                    fbLoginManager.logOut()
                }
            }
        })
    }

    func getFBUserData(){
        if((FBSDKAccessToken.currentAccessToken()) != nil){
            FBSDKGraphRequest(graphPath: "me", parameters: ["fields": "id, name, first_name, last_name, picture.type(large), email"]).startWithCompletionHandler({ (connection, result, error) -> Void in
                if (error == nil){
                    self.dict = result as NSDictionary
                    println(result)
                    println(self.dict)
                    NSLog(self.dict.objectForKey("picture")?.objectForKey("data")?.objectForKey("url") as String)
                }
            })
        }
    }
}