How to reload present view controller swift? - ios

Question

I have two Present view controllers. The thing i want to do is when the second Present view controller is dismissed it will automatically reload the first present view controller(Table view). note: first view controller holds a table view, basically i want to reload the table view of first controller.
ViewWillAppear code:
override func viewWillAppear(_ animated: Bool) {
tableViewReloadFromCreateProductVC()
}
func tableViewReloadFromCreateProductVC () {
tableView.reloadData()
}
Calling from second view controller code:
SecondViewController.tableViewReloadFromCreateProductVC()
navigationController?.popViewController(animated: true)
dismiss(animated: true, completion: nil)

Answer 1

FirstViewController calling 2nd view controller
#IBAction func CallSecondViewButton(_ sender: Any) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "YourViewControllerIdentifier") as! YourViewController
controller.modalPresentationStyle = .fullScreen
self.present(controller, animated: true, completion: nil)
}
just write the code in viewWillAppear() method of the view controller that you want to reload like this
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
//perform api call if any
yourTableView.reloadData()
}
2nd view controller
#IBAction func CloseButton(_ sender: Any) {
self.dismiss(animated: true, completion: nil)
}
after dissmissing the viewWillAppear method of firstViewController will autometically called.
The First two snippets are for first view controller and the last one is for second view controller

Answer 2

Reloading the entire table view could sometimes be costly and it also sounds like you're making an API call as well so unless you want your table view to be reloaded and the API call made every time the view controller becomes visible whether or not you've made changes to it, you want the reloading to be done only when it's necessary.
You can try it in a few different ways:
class CreateProductVC: UITableViewController {
#IBAction func presentSecondVC() {
if let secondVC = storyboard?.instantiateViewController(identifier: "SecondVC") as? SecondViewController {
secondVC.delegate = self
present(secondVC, animated: true, completion: nil)
}
}
}
class SecondViewController: UIViewController {
weak var delegate: CreateProductVC?
#IBAction func dismissSecondVC() {
self.dismiss(animated: true) {
self.delegate?.tableView.reloadData()
}
}
}
or
class CreateProductVC: UITableViewController {
#IBAction func presentSecondVC() {
if let secondVC = storyboard?.instantiateViewController(identifier: "SecondVC") as? SecondViewController {
secondVC.isDismissed = { [weak self] in
self?.tableView.reloadData()
}
present(secondVC, animated: true, completion: nil)
}
}
}
class SecondViewController: UIViewController {
var isDismissed: (() -> Void)?
#IBAction func dismissSecondVC() {
self.dismiss(animated: true) {
self.isDismissed?()
}
}
}
or if you want more fine-grained control over what to do with the new data:
protocol ReloadVC {
func reload(_ value: String)
}
class CreateProductVC: UITableViewController, ReloadVC {
var dataSource: [String]! {
didSet {
tableView.reloadData()
}
}
#IBAction func presentSecondVC() {
if let secondVC = storyboard?.instantiateViewController(identifier: "SecondVC") as? SecondViewController {
secondVC.delegate = self
present(secondVC, animated: true, completion: nil)
}
}
func reload(_ value: String) {
dataSource.append(value)
}
}
class SecondViewController: UIViewController {
var delegate: ReloadVC?
#IBAction func dismissSecondVC() {
self.dismiss(animated: true) {
let someValue = "Some Value"
self.delegate?.reload(someValue)
}
}
}