IOS Session Facebook SDK 4

Question

I am having a problem with the new FacebookSDK for iOS.

I can successfully log into the system and get the necessary information, but when I open the application again and intend to skip the registration process, the session that I check is zero.

This is my AppDelegate:

 class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { self.window = UIWindow(frame: UIScreen.mainScreen().bounds) self.window!.rootViewController = LogInViewController() self.window!.makeKeyAndVisible() FBSDKProfile.enableUpdatesOnAccessTokenChange(true) return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions) } func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject?) -> Bool { return FBSDKApplicationDelegate.sharedInstance().application(application, openURL: url, sourceApplication: sourceApplication, annotation: annotation) } func applicationDidBecomeActive(application: UIApplication) { FBSDKAppEvents.activateApp() } } 

And this is my Facebook login controller:

 class LogInViewController: UIViewController, FBSDKLoginButtonDelegate { // MARK: Properties @IBOutlet weak var logInView: FBSDKLoginButton! // MARK: Init init() { super.init(nibName: "LogInViewController", bundle: nil) } required init(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } // MARK: View Delegates override func viewDidLoad() { super.viewDidLoad() if (FBSDKAccessToken.currentAccessToken() != nil) { // User is already logged in, do work such as go to next view controller. println(FBSDKAccessToken.currentAccessToken().tokenString) self.goToNavigation() } else { logInView.readPermissions = ["public_profile", "email", "user_friends"] logInView.delegate = self } } // MARK: Facebook Delegate Methods func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) { println("User Logged In") if ((error) != nil) { // Process error } else if result.isCancelled { // Handle cancellations } else { // If you ask for multiple permissions at once, you // should check if specific permissions missing if result.grantedPermissions.contains("email") { // Do work returnUserData() } } } func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) { println("User Logged Out") } func returnUserData() { let graphRequest : FBSDKGraphRequest = FBSDKGraphRequest(graphPath: "me", parameters: nil) graphRequest.startWithCompletionHandler({ (connection, result, error) -> Void in if ((error) != nil) { // Process error println("Error: \(error)") } else { println("fetched user: \(result)") let userName : NSString = result.valueForKey("name") as! NSString println("User Name is: \(userName)") let userEmail : NSString = result.valueForKey("email") as! NSString println("User Email is: \(userEmail)") } self.goToNavigation() }) } func goToNavigation() { // Creating a navigation controller with MainMenuViewController at the root of the navigation stack. let navController = UINavigationController(rootViewController: MainMenuViewController()) self.presentViewController(navController, animated:true, completion: nil) } } 

When I check if (FBSDKAccessToken.currentAccessToken() != nil) , I always get null for the session, although the button title is "Exit".

What could be the problem? Any suggestions are welcome!

Answer 1

The answer to yourself is good. For more information, you can use the custom facebook button, and you can call up the fetch data when the access token actually receives the login process.

Log in using the custom button and access token.

Get user information on facebook sdk 4.x

Swift

 @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){ println(result) } }) } } 

Exit:

 { email = " ashishkakkad8@gmai l.com"; "first_name" = Ashish; id = 910855688971343; "last_name" = Kakkad; name = "Ashish Kakkad"; picture = { data = { "is_silhouette" = 0; url = "https://fbcdn-profile-a.akamaihd.net/hprofile-ak-xpf1/v/t1.0-1/p200x200/10394859_900936369963275_5557870055628103117_n.jpg?oh=fefbfca1272966fc78286c36741f9ac6&oe=55C89225&__gda__=1438608579_9133f15e55b594f6ac2306d61fa6b6b3"; }; }; } 

Objective-c

Sign in with Facebook SDK 4.x

Add the following code to the facebook login button:

 FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init]; [login logInWithReadPermissions:@[@"email"] handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) { if (error) { // Error } else if (result.isCancelled) { // Cancelled } else { if ([result.grantedPermissions containsObject:@"email"]) { [self getFBResult]; } } }]; 

Get Facebook Results Method:

 -(void)getFBResult { if ([FBSDKAccessToken currentAccessToken]) { [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me" parameters:@{@"fields": @"id, name, first_name, last_name, picture.type(large), email"}] startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) { if (!error) { NSLog(@"fb user info : %@",result); } else { NSLog(@"error : %@",error); } }]; } } 

You can change the permission fields as you want.

Answer 2

Solved! Thank you, a bunch of suggestions, Vijay Masival!

As in the proposed post, I solved the problem using the NSNotificationCenter observer for FBSDKAccessTokenDidChangeNotification:

  override func viewDidLoad() { super.viewDidLoad() NSNotificationCenter.defaultCenter().addObserver(self, selector:"checkLogIn", name: FBSDKAccessTokenDidChangeNotification, object: nil) } func checkLogIn() { if (FBSDKAccessToken.currentAccessToken() != nil) { // User is already logged in, do work such as go to next view controller. println(FBSDKAccessToken.currentAccessToken().tokenString) self.goToNavigation() } else { logInView.readPermissions = ["public_profile", "email", "user_friends"] logInView.delegate = self } }