How to login with Facebook in Swift

In this blog I will tell you how to login with facebook in Swift which is very important nowadays for quick signup as users don't have time to fill the forms.

Facebook is providing is SDK which is written in Obj-C and we will implement this in our swift project using the Bridging Header file. Below will be the step by step guide to implement the login .

• Download the FACEBOOK SDK and plaese check the requirements mentioned on the link.
• Go to this link Create a new iOS App and fill the necessary details of your app.
• Now go to your Xcode project manually drag the "FacebookSDKCoreKit.Framework" to your project.
• Now Create the Bridging-Header.h file and import the following files into that header.

                  #ifndef Project_Bridging_Header_h
                  #define Project_Bridging_Header_h
  
                  #import 
  
                  #endif’
                  

• Now add the following method into your app delegate file so that on facebook login click the app should redirect to your facebook App.

                  func application(application: UIApplication,
                      openURL url: NSURL,
                      sourceApplication: String?,
                      annotation: AnyObject?) -> Bool {
                      return FBSDKApplicationDelegate.sharedInstance().application(
                          application,
                          openURL: url,
                          sourceApplication: sourceApplication,
                          annotation: annotation)
                      }
              

• Go to your info.plist file and do the following shown in the image
• Add this into your viewControllers viewDidLoad() method

                  if (FBSDKAccessToken.currentAccessToken() != nil){
                  
                      // TODO IF THE USER IS ALREADY LOGIN
                      
                  }else{
                      let facebookLoginButton: FBSDKLoginButton = FBSDKLoginButton()
                      self.view.addSubview(facebookLoginButton)
                      facebookLoginButton.center = self.view.center
                      facebookLoginButton.readPermissions = ["public_profile", "email"]
                      facebookLoginButton.delegate = self
                      
                  }
              

• Extend the "FBSDKLoginButtonDelegate"

                  class ViewController: UIViewController,FBSDKLoginButtonDelegate {
              

• Finally, add the delegate methods of FBSDKLoginButtonDelegate

                  // Facebook Delegate Methods
                  func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
                  if ((error) != nil){
                      println("Error: \(error)")
                  }else if result.isCancelled {
                      // Handle cancellations
                  }else {
                          ActivityIndicator.shared.showProgressView(self.view)
                          self.returnUserData()
                      }
                  }
      
                  // Facebook logout button
                  func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
                      println("User Logged Out")
                  }
      
                  // Getting the user data from FaceBook
                  func returnUserData(){
                      let graphRequest : FBSDKGraphRequest = FBSDKGraphRequest(graphPath: "me", parameters: nil)
                      graphRequest.startWithCompletionHandler({ (connection, result, error) -> Void in
                      if (error) != nil   {
                          println("Error: \(error)")
                      }else{
                          self.storingFacebookData(result)
                      }
                  })
              }
              

• Now you are ready to use login with facebook functionality in your project .

Thanks