Protocols and delegation in swift 3 not sending values between viewcontrollers - ios

Question

I have two viewcontrollers(SignInViewcontroller.swift and ProfilePage.swift)
I want to pass the string from SignInViewcontroller to ProfilePage viewcontroller.
I created a protocol in SignInViewcontroller.And I delegate the method in ProfilePage controller.When I send the string through protocols I didn't receive that string in ProfilePage viewcontroller Where I am wrong.please help me to solve.
Here is my code:
SignInViewController.swift
protocol sendTokenDelegate: class {
func sendToken(login:String)
}
class SignInViewController: UIViewController {
weak var delegateToken:sendTokenDelegate?
func loginAzure(email: String, password: String) {
token = "abcdefgh"
self.delegateToken?.sendToken(login: token)
}
}
ProfilePage.swift
class ProfilePage: UIViewController, UITableViewDelegate, UITableViewDataSource, sendTokenDelegate {
override func viewDidLoad() {
let signInVC = SignInViewController()
signInVC.delegateToken = self
}
func sendToken(login: String) {
self.logInToken = login
print("Login Token in Profile Page is \(login)")
}
}

Answer 1

In that case, you need object that will store token from SignInViewController, until ProfilePage is requesting it.
class TokenStorage {
static let shared = TokenStorage()
public var token: String = ""
}
then you receive token call:
TokenStorage.shared.token = receivedToken
and in ProfilePage request it:
print(TokenStorage.shared.token)

Answer 2

If you are coming from SignUpViewController to ProfilePageViewController, you can pass the string values upon navigation after getting the singIn token you want from your logingAzure() I assume:
If you navigate using segues -> self.performSegue(withIdentifier: "signUpToProfile", sender: self)
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "signUpToProfile" {
if let profileVC : ProfilePageViewController =
segue.destination as? ProfilePageViewController {
profileVC.loginToken = token
}
}
}
If you are using self.navigationController?.pushViewController
let storyboard = UIStoryboard(name: "Profile", bundle: Bundle.main)
if let profileVC = storyboard.instantiateViewController(withIdentifier:
"ProfilePageViewController") as? ProfilePageViewController {
profileVC.loginToken = token
}
EDIT
If you are not going to profilePage directly from SignUpViewController,
then just save the token in your Keychain OR UserDefaults.
Do this by creating a SessionManager singleton to handle tokens and other resources when logging in or signing up

Answer 3

Just use "prepare for segue"
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "ProfileSegue" {
if let vc = segue.destination as? ProfilePage {
vc.token = self.token
}
}
}

Answer 4

When you are going to NextVC that doesn't exist in the navigation controller then you have to bind data with the instance of the class when you are pushing just like that:
let vc = UIStoryboard(name: "ProfilePage", bundle: nil).instantiateInitialViewController() as! ProfilePage
vc. logInToken = "abcdefgh"
self.navigationController?.pushViewController(vc, animated: true)
class ProfilePage: UIViewController {
var logInToken = "" // you will receive the token in this variable.
}
In you case, it seems like ProfilePage doesn't exist.
NOTE:- Delegate will use just opposite case when you want to pass the value from ProfilePage to SignInViewController.
OR
If your all API wants the token so you can declare at the class level or save it to UserDefauls:
1)
var logInToken = "" // your variable visible the entire application classes
class ProfilePage: UIViewController {
}
func loginAzure(email: String, password: String) {
logInToken = "abcdefgh" //Just assign and use it
}
2)
UserDefaults.standard.set("aasdfa", forKey: "token")
let token = UserDefaults.standard.value(forKey: "token"
Also, you are doing the bad coding you have to understand the OOP's
let signInVC = SignInViewController()
signInVC.delegateToken = self
This will reperensent the seprate instance in the memory and every
object has its own properties and behavior.

Answer 5

Try using:
protocol sendTokenDelegate: class {
func sendToken(login:String)
}
class SignInViewController: UIViewController {
weak var delegateToken:sendTokenDelegate?
func loginAzure(email: String, password: String) {
token = "abcdefgh"
if self.delegateToken != nil{
self.delegateToken?.sendToken(login: token)
}
}
}
class ProfilePage: UIViewController, UITableViewDelegate, UITableViewDataSource, sendTokenDelegate {
override func viewDidLoad() {
//get your instantiateViewController from storyboard
let signInVC = self.storyboard?.instantiateViewController(withIdentifier: "SignInViewControllerIdentifire") as! SignInViewController
signInVC.delegateToken = self
}
func sendToken(login: String) {
self.logInToken = login
print("Login Token in Profile Page is \(login)")
}
}