How can I properly reload the UIViewController after dismiss method is called? - swift

Question

I have 2 viewControllers named vcA and vcB.
vcA has navigationController and vcB is just viewController which don't have navigationController.
I saved text data in a file in vcB, and I wanna show that text in vcA when I come back to vcA after the dismiss method is called.
I thought reloading vcA after dismiss is called is the proper way to show text, but I figured out that it might be difficult to do that between vcA and vcB, because vcA has navigationController but vcB doesn't have navigationController.
How can I refresh vcA?

Answer 1

You can use self.present over self.dismiss. Like this:
let vc = vcA()
And here you can pass data. For example, if vcA() has a var called text that is a string you can use vc.text = "something". And this data will go with the self.present method
vc.modalPresentationStyle = .fullScreen
self.present(vc,animated: true, completion: nil)

Answer 2

You can pass the value back to the presenting view controller using the protocol/delegate pattern. Following is an example of how to pass a text from a text field in vcB to vcA as vcB is being dismissed so you can substitute that with the value you want to pass.
protocol ValuePassingDelegate {
func didPassValue(of text: String)
}
class ViewControllerA: UIViewController, ValuePassingDelegate {
let label = UILabel(frame: CGRect(origin: CGPoint(x: 0, y: 100), size: CGSize(width: 200, height: 100)))
let button = UIButton(type: .system)
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(label)
label.text = "Initial text"
label.textAlignment = .center
button.frame = CGRect(origin: CGPoint(x: 0, y: 300), size: CGSize(width: 200, height: 100))
button.setTitle("Button", for: .normal)
button.addTarget(self, action: #selector(buttonHandler), for: .touchUpInside)
view.addSubview(button)
}
#objc func buttonHandler() {
let vcB = ViewControllerB()
vcB.delegate = self
self.navigationController?.pushViewController(vcB, animated: true)
}
func didPassValue(of text: String) {
DispatchQueue.main.async {
self.label.text = text
}
}
}
class ViewControllerB: UIViewController {
let textField = UITextField(frame: CGRect(origin: .zero, size: CGSize(width: 200, height: 100)))
var delegate: ValuePassingDelegate?
override func viewDidLoad() {
super.viewDidLoad()
textField.layer.borderWidth = 1
textField.layer.borderColor = UIColor.black.cgColor
view.addSubview(textField)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
delegate?.didPassValue(of: textField.text ?? "")
}
}

Answer 3

The way that I followed for this purpose is :
in vcB I added:
internal var senderVC: UIViewController?
in vcA I added:
vcB.senderVC = self
in vcB I added:
if let firstVC = self.senderVC as? vcA { firstVC.tableView.reloadData(); }