Delegate is still nil - ios

Question

I am passing user data from a view controller called CreateNewAccount to another view controller called ThanksForJoining. For some reason my delegate is nil. I am using a segue in order to set my vc.delegate to self (= self) and the segue identifier "thanksForJoining" refers to the segue that connects CreateNewAccount to ThanksForJoining on the storyboard. Somehow though, the delegate remains nil.
CreateNewAccount:
import UIKit
protocol UserInfoDelegate {
func sendUserInfo(firstName: String, lastName: String, username: String, password: String)
}
class CreateNewAccount: UIViewController{
#IBOutlet weak var FNInput: UITextField!
#IBOutlet weak var LNInput: UITextField!
#IBOutlet weak var usernameInput: UITextField!
#IBOutlet weak var passwordInput: UITextField!
var infoDelegate: UserInfoDelegate?
#IBAction func sendInfo(_ sender: Any) {
if(infoDelegate != nil){
if(FNInput.text != nil && LNInput.text != nil && usernameInput.text != nil && passwordInput.text != nil){
let firstName = FNInput.text
let lastName = LNInput.text
let username = usernameInput.text
let password = passwordInput.text
infoDelegate?.sendUserInfo(firstName: firstName!, lastName: lastName!, username: username!, password: password!)
}
}
}
}
ThanksforJoining:
import UIKit
class ThanksForJoining: UIViewController, UserInfoDelegate {
#IBOutlet weak var fName: UILabel!
func sendUserInfo(firstName: String, lastName: String, username: String, password: String) {
print(firstName)
fName.text = firstName
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "thanksForJoining") {
let createNewAccount: CreateNewAccount = segue.destination as! CreateNewAccount
createNewAccount.infoDelegate = self
}
}
}

Answer 1

First of all, you need to confirm that:
You connected CreateNewAccount to ThanksForJoining via a segue.
The segue's Identifier is set to thanksForJoining correctly
(Be careful about the letter cases.)
If any of the two is not true, you have lost a little time and I have lost my time to prepare for a big typhoon. Update your question to clarify what's happening and wait for someone to help you...
Assuming two things above, prepare(for:sender:) is called on the source view controller. You need to implement it in your CreateNewAccount class.
CreateNewAccount:
import UIKit
class CreateNewAccount: UIViewController {
#IBOutlet weak var firstNameInput: UITextField!
#IBOutlet weak var lastNameInput: UITextField!
#IBOutlet weak var usernameInput: UITextField!
#IBOutlet weak var passwordInput: UITextField!
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "thanksForJoining" {
let destinationVC = segue.destination as! ThanksForJoining
if
let firstName = firstNameInput.text, !firstName.isEmpty,
let lastName = lastNameInput.text, !lastName.isEmpty,
let username = usernameInput.text, !username.isEmpty,
let password = passwordInput.text, !password.isEmpty
{
destinationVC.receiveUserInfo(firstName: firstName, lastName: lastName, username: username, password: password)
}
}
}
}
ThanksForJoining:
import UIKit
class ThanksForJoining: UIViewController {
var firstName: String?
#IBOutlet weak var firstNameLabel: UILabel!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
firstNameLabel.text = firstName
}
func receiveUserInfo(firstName: String, lastName: String, username: String, password: String) {
print(firstName)
self.firstName = firstName
}
}
Seems delegate pattern is sort of too much for your purpose and you just need to define a data passing method in the destination view controller ThanksForJoining.
I assume you have connected your segue from some button of your CreateNewAccount. If the segue is connected from the view controller (not from a button), the code above needs small modification.
But anyway, in your original code, the method prepare(for:sender:) in ThanksForJoining would never be called, so the delegate would never be set. Thus, the delegate remains nil.

Answer 2

First you need a reference to the CreateNewAccount class in the class ThanksForJoining class. Then you need to activate the delegate by setting it equal to self in the ThanksForJoing class in viewDidLoad.
class ThanksForJoining: UIViewController, UserInfoDelegate {
var createNewAccount: CreateNewAccount?
override func viewDidLoad() {
super.viewDidLoad()
createNewAccount?.infoDelegate = self
}
{
Then your delegate methods will work.

Answer 3

The only possible issue is segue identifier mismatch in code and storyboard
In the story board, select the segue between two VCs
And then go the attributes inspector and set the ID "thanksForJoining" in "Identifier" field
Some suggestions
If your intention is to check whether user has entered all the fields before sending the data back, then this code will serve the purpose better
if (infoDelegate != nil) {
if let firstName = FNInput.text, firstName.count>0,
let lastName = LNInput.text, lastName.count>0,
let username = usernameInput.text, username.count>0,
let password = passwordInput.text, password.count>0 {
infoDelegate?.sendUserInfo(firstName: firstName, lastName: lastName, username: username, password: password)
}
}