I want to modal tableView Cell data backward to the main View - ios

Question

I want to modalViewController's table cell data pass to the main View.
Using Protocol delegate. but
Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
This error occur where i remark at the ModalViewController.
Using Protocol method is wrong?.
I use this protocol code another mini project textField's text data pass back and forward. In there it works well.
So i use it in cell data pass
What am i Miss ? Please help.
Bottom Link is my Simulator.
ModalTableViewDataPass
**MainViewController**
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var show: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
show.placeholder = "HAHA"
show.delegate = self
show.inputView = UIView()
show.addTarget(self, action: #selector(textFieldDidBeginEditing(_:)), for: .touchUpInside)
// Do any additional setup after loading the view.
}
#objc func textFieldDidBeginEditing(_ textField: UITextField) {
if textField == show {
moveToFindAdrVC()
print("주소 검색해라잉")
}
}
func moveToFindAdrVC() {
let modalVC = storyboard?.instantiateViewController(identifier: "ModalViewController") as? ModalViewController
self.present(modalVC!, animated: true, completion: nil)
}
}
extension ViewController: PassDataToVc {
func passData(str: String){
show.text = str
}
}
ModalTableView
import UIKit
class ModalViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var data = ["as","df","qw","er"]
var delegate: PassDataToVc!
#IBOutlet weak var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
table.delegate = self
table.dataSource = self
// Do any additional setup after loading the view.
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
cell.textLabel?.text = data[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let passData = data[indexPath.row]
let sb = storyboard?.instantiateViewController(identifier: "ViewController") as? ViewController
//sb?.show.text = passData
delegate.passData(str: passData)//Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
self.dismiss(animated: true, completion: nil)
}
}
protocol PassDataToVc {
func passData(str: String)
}

Answer 1

delegate in ModalViewController is never set, hence it's nil.
But there is a more convenient solution, protocol/delegate is not needed at all.
Delete the code related to protocol/delegate
extension ViewController: PassDataToVc {
func passData(str: String){
show.text = str
}
}
var delegate: PassDataToVc!
and replace
delegate.passData(str: passData)
with
(presentingViewController as? ViewController)?.show.text = passData