Calling segue with swift if user already logged in with facebook - ios

Question

I have been following this tutorial on how to make a facebook login with swift. http://letsbuildthatapp.com/2016/03/26/swift-facebook-login-sdk-and-getting-users-email/
But, when i dismiss the app by double clicking on home button and sliding up the application I see my login screen with one difference. Button's text has changed to logout.
What i want to do is automatically skipping that login page and performing this segue: self.performSegueWithIdentifier("redirectAfterLogin", sender: self)
I come across this article yet I couldn't fix the issue by myself and now I'm little bit confused.
How to check if user is logged in with FBSDKLoginKit in iOS?
Below you can see my AppDelegate.swift and LoginVC.swift files. How can I fix this?
AppDelegate.swift
import UIKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, CNPPopupControllerDelegate {
var window: UIWindow?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
return true
}
func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject) -> Bool {
return FBSDKApplicationDelegate.sharedInstance().application(application, openURL: url, sourceApplication: sourceApplication, annotation: annotation)
}
func applicationWillResignActive(application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
func applicationDidEnterBackground(application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(application: UIApplication) {
// Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
}
LoginVC.swift
import UIKit
import KASlideShow
class LoginVC: UIViewController, KASlideShowDelegate, FBSDKLoginButtonDelegate {
let loginButton: FBSDKLoginButton = {
let button = FBSDKLoginButton()
button.readPermissions = ["email"]
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
// do stuff here
view.addSubview(loginButton)
loginButton.center = view.center
loginButton.readPermissions = ["public_profile", "email", "user_friends"]
loginButton.delegate = self // Remember to set the delegate of the loginButton
if let token = FBSDKAccessToken.currentAccessToken() {
fetchProfile()
}
if FBSDKAccessToken.currentAccessToken() != nil {
print("1")
self.performSegueWithIdentifier("redirectAfterLogin", sender: self)
}
}
func fetchProfile(){
print("fetching profile..")
let params = ["fields": "email, first_name, last_name, picture.type(large)"]
FBSDKGraphRequest(graphPath: "me", parameters: params).startWithCompletionHandler{ (connection, result, var error) -> Void in
if error != nil {
print (error)
return
}
if let email = result["email"] as? String {
print(email)
NSUserDefaults.standardUserDefaults().setObject(email, forKey: "email")
}
if let first_name = result["first_name"] as? String {
print(first_name)
NSUserDefaults.standardUserDefaults().setObject(first_name, forKey: "first_name")
}
if let last_name = result["last_name"] as? String {
print(last_name)
NSUserDefaults.standardUserDefaults().setObject(last_name, forKey: "last_name")
}
if let picture = result["picture"] as? NSDictionary, data=picture["data"] as? NSDictionary, url=data["url"] as? String {
print(url)
NSUserDefaults.standardUserDefaults().setObject(url, forKey: "url")
}
NSUserDefaults.standardUserDefaults().synchronize()
print(result) // this prints whole FBSDKGraphRequest API response
}
}
func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
print("login completed")
fetchProfile()
self.performSegueWithIdentifier("redirectAfterLogin", sender: self)
}
func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
}
func loginButtonWillLogin(loginButton: FBSDKLoginButton!) -> Bool {
return true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

What you'll need to do is in appDelegate on
application(application: UIApplication, didFinishLaunchingWithOptions launchOptions:
if let root = UIApplication.sharedApplication().windows[0].rootViewController as? UINavigationController {
if CONDITION {
root.viewControllers = [USER_HOMEPAGE]
} else {
root.viewControllers = [USER_LOGIN]
}
}