IOS: check if a user is registered using Facebook?

Question

I started working on an iOS application on Xcode using Swift and storyboards. I have a requirement when, when I click the button, I will show the user’s Facebook profile information on the screen (only if the user is signed in using Facebook), but if he is not signed in, he will automatically go to the login screen and will be shown again when he successfully logs in profile view.

How can i do this?

Answer 1

If you use the SDK to log in to Facebook, call

FBSDKAccessToken.currentAccessToken() 

This will not be zero if the user is logged in.

https://developers.facebook.com/docs/facebook-login/ios/v2.3#token

Answer 2

With the latest version of the Facebook SDK, you can check this as follows:

 if FBSDKAccessToken.current() != nil { // logged in } else { // not logged in } 

They recently changed from FBSDKAccessToken.currentAccessToken() to FBSDKAccessToken.current()

Answer 3

For a more convenient and standard code in swift, you can use this next piece of code. BTW I am using Swift 2.2 and Xcode 7.3.1.

 if let loggedInUsingFBTokenCheck = FBSDKAccessToken.currentAccessToken(){ //User is already logged-in. Please do your additional code/task. }else{ //User is not logged-in. Allow the user for login using FB. } 

If you want to load a specific viewController during application startup based on login verification, you can put this code in your AppDelegate project and check inside -

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { //Check here for login } 

Thanks.

Answer 4

in the Swift 5 SDK, use the following code:

 import FBSDKCoreKit if AccessToken.isCurrentAccessTokenActive { print("your session is active") }