Facebook Login for iOS - Advanced

- Setting the Authorization Type

Login Review

If your app asks for more than public_profile and email, Facebook must review it before you release it. Learn more about the review process and what's required to pass review.

Instead of using the Facebook-branded login button (explained in Facebook Login for iOS - Quickstart) you may want to design a custom layout and behavior. In the following code example we invoke the login dialog using the login manager class (LoginManager) and a custom button (UIButton). You can use any other custom user interface or event handling to invoke the login dialog.

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        // Add a custom login button to your app
        let loginButton = UIButton(type: .custom)
        loginButton.backgroundColor = .darkGray
        loginButton.frame = CGRect(x: 0, y: 0, width: 180, height: 40)
        loginButton.center = view.center
        loginButton.setTitle("My Login Button", for: .normal)

        // Handle clicks on the button
        loginButton.addTarget(self, action: #selector(loginButtonClicked), for: .touchUpInside)

        view.addSubview(loginButton)
    }
  
  
    // Once the button is clicked, show the login dialog
    func loginButtonClicked() {
        let loginManager = LoginManager()
        loginManager.logIn(permissions: ["public_profile"], from: self) { result, error in
            if let error = error {
                print("Encountered Erorr: \(error)")
            } else if let result = result, result.isCancelled {
                print("Cancelled")
            } else {
                print("Logged In")
            }
        }
    }
}

Using the Interface Builder

These steps are required for version 12.0.0 and later of the Facebook iOS SDK. Apps using the Interface Builder may crash if you have not completed this step.

To add the login button graphically in Interface Builder:

Add a UIButton object to your layout. Set constraints to position it.
In Identity inspector change the Class property to FBSDKLoginButton.

Now your layout looks like this:

Note: Do not set a module for the FBSDKLoginButton class. It should show None:

Note: You may see the following error in Xcode logs due to a known issue with XCFrameworks:

[Storyboard] Unknown class FBSDKLoginButton in Interface Builder file.

You can fix this by "pre-loading" the FBSDKLoginButton class before the storyboard loads by adding the following to your application:didFinishLaunchingWithOptions: method:

// For Swift
_ = FBLoginButton.self

// For Objective-C
[FBSDKLoginButton class];

Access Tokens

Notifications

You can track AccessToken.current changes with the .AccessTokenDidChange notification in NotificationCenter. This allows you to respond to changes in the user's login state:

NotificationCenter.default.addObserver(
    forName: .AccessTokenDidChange,
    object: nil,
    queue: .main
) { notification in
    if notification.userInfo?[AccessTokenDidChangeUserIDKey] != nil {
        // Handle user change
    }
}

The iOS SDK can update AccessToken.current over time, such as when the SDK refreshes a token with a longer expiration date. Therefore, you should check the userInfo dictionary in the notification for AccessTokenDidChangeUserIDKey to determine if the user has changed.

Profiles

Profile contains public profile information, allowing you to personalize your app with the user's name and profile picture. You can load the logged in user's profile using loadCurrentProfile(completion:).

Profile.loadCurrentProfile { profile, error in
    if let firstName = profile?.firstName {
        print("Hello, \(firstName)")
    }
}

You can set the enableUpdatesOnAccessTokenChange property to true to have the profile automatically loaded to Profile.current. This also lets you to observe the .ProfileDidChange notification to respond to profile changes:

Profile.enableUpdatesOnAccessTokenChange(true)
NotificationCenter.default.addObserver(
    forName: .ProfileDidChange,
    object: nil,
    queue: .main
) { notification in
    if let currentProfile = Profile.current {
        // Update for new user profile
    }
}

Showing Profile Pictures

The FBProfilePictureView class provides an easy way to display someone's Facebook profile picture. Simply set the profileID property on the instance. You can set it to a value of AccessToken.current.userID to show the profile picture of the person currently logged in.

let profilePictureView = FBProfilePictureView()
profilePictureView.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
profilePictureView.profileID = AccessToken.current!.userID
view.addSubview(profilePictureView)

Setting the Authorization Type

The default auth_type for Facebook Login buttons in the Facebook SDK for iOS is rerequest. If you want to avoid requesting permissions that were previously denied, set auth_type to nil. You can also set it to reauthorize to show the data reauthorization dialog if the user's data access has expired.

The following example shows how to set the auth_type in Swift.

let loginButton = FBLoginButton()

// Set to nil for no auth_type
button.authType = nil

// Or set to reauthorize
button.authType = .reauthorize

The following example shows how to set the auth_type using a login configuration with a login manager.

let config = LoginConfiguration(
    permissions: [],
    tracking: .enabled,
    messengerPageId: nil,
    authType: nil
)

let loginManager = LoginManager()
loginManager.logIn(viewController: self, configuration: config!) { loginResult in
    // Do something with loginResult
}

Facebook Login for iOS - Advanced

- Login Review

- Custom Login Button

- Using the Interface Builder

- Access Tokens

- Profiles

- Track Profile Pictures