Custom Facebook Login button iOS

New URL of documentation about custom buttons:

https://developers.facebook.com/docs/facebook-login/ios/advanced

Or if you just want to know what to do when auth button tapped do this in "Button tapped" method (don't forget to link that method with your button):

#import <FBSDKLoginKit/FBSDKLoginKit.h>
#import <FBSDKCoreKit/FBSDKCoreKit.h>

Then

- (IBAction)facebookAuthButtonTapped:(id)sender {

    FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
    [login
     logInWithReadPermissions: @[@"public_profile"]
     fromViewController:self
     handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
         if (error) {
             NSLog(@"Process error");
         } else if (result.isCancelled) {
             NSLog(@"Cancelled");
         } else {
             NSLog(@"Logged in");
         }
     }];
}

SwiftUI solution

import SwiftUI
import FBSDKLoginKit
import Firebase

struct FaceBookLoginButton: UIViewRepresentable {
    
    func makeCoordinator() -> FBSignInCoordinator {
        return FBSignInCoordinator()
    }
    
    func makeUIView(context: UIViewRepresentableContext<FaceBookLoginButton>) -> FBLoginButton {
        let view = FBLoginButton()
        view.permissions = ["email"]
        view.delegate = context.coordinator
        
        // normal
        view.setTitleColor(.clear, for: .normal)
        view.setImage(nil, for: .normal)
        view.setBackgroundImage(nil, for: .normal)
        
        // tapped
        view.setTitleColor(.clear, for: .highlighted)
        view.setImage(nil, for: .highlighted)
        view.setBackgroundImage(nil, for: .highlighted)
        return view
    }
    
    func updateUIView(_ uiView: FBLoginButton, context: UIViewRepresentableContext<FaceBookLoginButton>) {}
    
}

Updated for Swift 3

@IBAction func fblogin(_ sender: Any) {
    let loginManager = LoginManager()
    UIApplication.shared.statusBarStyle = .default  // remove this line if not required 
    loginManager.logIn([ .publicProfile,.email ], viewController: self) { loginResult in
        print(loginResult)

        //use picture.type(large) for large size profile picture
        let request = GraphRequest(graphPath: "me", parameters: ["fields":"email,name,gender,picture"], accessToken: AccessToken.current, httpMethod: .GET, apiVersion: FacebookCore.GraphAPIVersion.defaultVersion)
        request.start { (response, result) in
            switch result {
            case .success(let value):
                print(value.dictionaryValue)
            case .failed(let error):
                print(error)
            }
        }
    }
}

For Objective-C

You can call this method on UIButton click event

-(void)fblogin{

   FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
    if ([UIApplication.sharedApplication canOpenURL:[NSURL URLWithString:@"fb://"]])
    {
        login.loginBehavior = FBSDKLoginBehaviorSystemAccount;
    }

    [login logInWithReadPermissions:@[@"public_profile", @"email"] handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
        if (error)
        {
            NSLog(@"Unexpected login error: %@", error);
            NSString *alertMessage = error.userInfo[FBSDKErrorLocalizedDescriptionKey] ?: @"There was a problem logging in. Please try again later.";
            NSString *alertTitle = error.userInfo[FBSDKErrorLocalizedTitleKey] ?: @"Oops";
            [[[UIAlertView alloc] initWithTitle:alertTitle
                                        message:alertMessage
                                       delegate:nil
                              cancelButtonTitle:@"OK"
                              otherButtonTitles:nil] show];
        }
        else
        {
            if(result.token)   // This means if There is current access token.
            {

                [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me"
                                                   parameters:@{@"fields": @"picture, name, email"}]
                 startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id userinfo, NSError *error) {
                     if (!error) {


                         dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
                         dispatch_async(queue, ^(void) {

                            dispatch_async(dispatch_get_main_queue(), ^{

                                // you are authorised and can access user data from user info object 

                             });
                         });

                     }
                     else{

                         NSLog(@"%@", [error localizedDescription]);
                     }
                 }];
            }
            NSLog(@"Login Cancel");
        }
    }];
}

Make you own custom button in the storyboard. Hook up the action to myButtonPressed.

- (void)viewDidLoad {
    [super viewDidLoad];
    self.loginButton = [[FBSDKLoginButton alloc] init];
    self.loginButton.hidden = YES;
}

- (void)myButtonPressed {
    [self.loginButton sendActionsForControlEvents: UIControlEventTouchUpInside];
}