Swift 3 - Passing data between a View Controller and after that to another 2 - ios

Question

I'm trying to perform a segue which it doesn't work.
What i'm trying to do is send the data which i have in a textfield in my View Controller(Main), after that i want to send it to a ViewController called OperationsController and after that send it to another Views (CreateController & ListController) so i can use that same data and send it to a php file and get data to populate a table view in ListController. And for CreateController to get the email (which is in short words the data) and perform a query based on the email and insert into the database.
Anyways i tried sending the data to Operations into a label and doesn't work.
This is my code
ViewController: .
import UIKit
class ViewController: UIViewController {
var datas:[Usuario]?
struct Usuario : Codable {
let correo: String?
let contrasena: String?
}
#IBOutlet weak var txtError: UILabel!
#IBOutlet weak var txtCorreo: UITextField!
#IBOutlet weak var txtContra: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func btnLogear(_ sender: Any) {
let urlString = "http://localhost:8080/swiftdb/logear.php"
guard let url = URL(string: urlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil {
print(error!.localizedDescription)
}
guard let data = data else { return }
//Implement JSON decoding and parsing
do {
//Decode retrived data with JSONDecoder and assing type of Article object
let articlesData = try JSONDecoder().decode([Usuario].self, from: data)
//Get back to the main queue
DispatchQueue.main.async {
self.datas = articlesData
let aarti = self.datas
for item in aarti! {
let correos = item.correo
let contras = item.contrasena
if(item.correo == self.txtCorreo.text && item.contrasena == self.txtContra.text){
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "OP") as! OpcionesController
self.present(nextViewController, animated:true, completion:nil)
self.performSegue(withIdentifier: "segue", sender: self)
self.txtError.text = " "
} else {
self.txtError.text = "Datos Incorrectos"
}
}
}
} catch let jsonError {
print(jsonError)
}
}.resume()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? OpcionesController{
destination.name = txtCorreo.text
}
}
}
OperationsController: .
import UIKit
class OpcionesController: UIViewController {
var name: String?
#IBOutlet weak var displayLbl: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
if let nametoDisplay = name {
displayLbl.text = name
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}

Answer 1

Before calling presentViewController add :
nextViewController.name = yourTextField.text
You could also delete the segue call. That is redundant.
Here is an example that I've used in the past :
#IBAction func doSegue(_ sender: UIButton) {
buttonTag = sender.tag
let storyboard = UIStoryboard (name: "Main", bundle: nil)
let resultVC = storyboard.instantiateViewController(withIdentifier: "ResultViewController")as! ResultViewController
// Communicate with new VC - These values are stored in the destination
// you can set any value stored in the destination VC here
resultVC.firstValue = buttonTag
resultVC.secondValue = randomOpponentValue()
self.navigationController?.pushViewController(resultVC, animated: true)
}

Answer 2

1.So get rid of this code, because if you are calling performSegue you don’t need that one.
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "OP") as! OpcionesController
self.present(nextViewController, animated:true, completion:nil)
2.Then in the prepareForSegue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == “YourSegueIdentifier" {
let destination: OpcionesController = segue.destination as! OpcionesController
destination.name = txtCorreo.text
}
}
3.Replace this code:
if let nametoDisplay = name {
displayLbl.text = name
}
with:
displayLbl.text = name