iOS Facebook login button with swift

Question

Just wondering what i'm doing wrong with the code below, the code inside the block facebookLogin.login(withReadPermissions:) never gets called.

  @IBAction func fbBtnPressed(sender: UIButton!) {
    let facebookLogin =  FBSDKLoginManager()

    facebookLogin.logIn(withReadPermissions: [ "email" ], from: self) { (facebookResult: FBSDKLoginManagerLoginResult?, facebookError:NSError?) in

        if facebookError != nil {
            print("Facebook login failed. Error \(facebookError)")
        } else {
            let accessToken = FBSDKAccessToken.current().tokenString
            print("Successfully logged in with facebook. \(accessToken)")
        }
    }

Answer 1

It's possible that facebookLogin is being deallocated when it goes out of scope at the end of the function call, before it has had time to complete.

Try move let facebookLogin = FBSDKLoginManager() into the containing (class) scope:

let facebookLogin =  FBSDKLoginManager()

@IBAction func fbBtnPressed(sender: UIButton!) {

    facebookLogin.logIn(withReadPermissions: [ "email" ], from: self) { (facebookResult: FBSDKLoginManagerLoginResult?, facebookError:NSError?) in

        // ...    
    }
}

Answer 2

Are you sure that the token existed when you ask for the permission? As stated in Facebook Login SDK ,

You should check the for availability of an existing token before you call the loginManager.

Else you would need to set the permission to your login button with self.facebookLogInButton.readPermissions = ["email"] as stated at the permission page I linked