FBSDKGraphRequestHandler Swift 3 error - swift

Question

I have tried to debug my entire app, and currently I am down to 3 errors, all the same error. I have spent hours trying to debug these last 3 errors on my own, but I haven't been successful. Of course, the 3 errors are the same, and I know once I debug one, I can debug all of them
The error is related to the Facebook SDK, specifically the FB SDK Graph Request Handler.
This is the code
func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: Error?) {
if let error = error {
print(error.localizedDescription)
return
}
else{
let credential = FacebookAuthProvider.credential(withAccessToken: FBSDKAccessToken.current().tokenString)
// If already anon user exists link with new user
if Auth.auth().currentUser != nil{
Auth.auth().currentUser!.link(with: credential) { (user, error) in
// ...
}
}
let req = FBSDKGraphRequest(graphPath: "me", parameters: ["fields": "email,first_name, last_name, birthday, gender"], tokenString: FBSDKAccessToken.current().tokenString, version: nil, httpMethod: "GET")
req ? .start(completionHandler: {
(connection, result, error: NSError!) - > Void in
if (error == nil) {
print("result \(result)")
Auth.auth() ? .signIn(with: credential) {
(user, error) in
if error != nil {
print("Login failed. \(error)")
} else {
print("Logged in! \(user)")
FirebaseUtility.sharedInstance.setUser(user!)
let name = String.init(format: "%# %#", result.value(forKey: "first_name") as!String, result.value(forKey: "last_name") as!String)
FirebaseUtility.sharedInstance.editUserValue(name, key: "name")
if (result.object(forKey: "gender") != nil) {
let gender = result.object(forKey: "gender") as!String
FirebaseUtility.sharedInstance.editUserValue(gender.capitalized, key: "gender")
}
if (result.object(forKey: "email") != nil) {
let gender = result.object(forKey: "email") as!String
FirebaseUtility.sharedInstance.editUserValue(gender.capitalized, key: "email")
}
if self.isSignupflow == true {
FirebaseUtility.sharedInstance.sendToken()
// this user hasn't completed his profile so show him profile page
let vc: SignupViewController = SignupViewController(nibName: "SignupViewController", bundle: nil)
self.present(vc, animated: true, completion: nil)
} else {
FirebaseUtility.sharedInstance.isFirstTimeUser {
(isFirstTimeUser) in
if isFirstTimeUser {
FirebaseUtility.sharedInstance.sendToken()
// this user hasn't completed his profile so show him profile page
let vc: SignupViewController = SignupViewController(nibName: "SignupViewController", bundle: nil)
self.present(vc, animated: true, completion: nil)
} else {
// take him into app
// self.loginSuccessful()
let vc: RecordViewControllerNew = RecordViewControllerNew(nibName: "RecordViewControllerNew", bundle: nil)
vc.isBackButtonHidden = true
self.present(vc, animated: true, completion: nil)
}
}
}
}
}
}
The error that occurs is:
Cannot convert value of type '(, _, NSError!) ->Void' to expected argument type 'FBSDKGraphRequestHandler!'
and it occurs on this line of the code
req ? .start(completionHandler: {
(connection, result, error: NSError!) - > Void
Any help would be appreciated, I know once this error is solved, more errors are going to be created, but that's just how coding works :)
Thank you!

Answer 1

FBSDKGraphRequestHandler having optional Error? as last argument not the NSError!, so change the completion block to req?.start(completionHandler: { (connection, result, error) in from req?.start(completionHandler: { (connection, result, error: NSError!) - > Void will reduce that error.
Also after changing this you get new warning like.
Expression of type 'FBSDKGraphRequestConnection?' is unused
So simply add _ = as prefix of req?.start.
_ = req?.start(completionHandler: { (connection, result, error) in
//Add your code here
})