Accessing data from different screens - swift - ios

Question

I am trying to get data from a different screen but for some reason, the variable does not update. here is the code so far
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let viewController: UIViewController = UIViewController()
switch (indexPath.row) {
case 0:
print("hello")
let vc = AddViewController()
vc.chosenDaily = true
dismiss(animated: true, completion: nil)
here I created a tableView and once the user clicks on the first index of my tableView I want to set a boolean variable to true and return to another screen. I declared this boolean variable on the other screen here.
var chosenDaily:Bool = false
on the same screen, I have a save button and want to print the result.
#IBAction func didTapSaveButton() {
if chosenDaily == true {
print("it's true")
} else if chosenDaily == false {
print("it's false")
}
}
but for some reason, the code doesn't update and returns false instead of true. can anyone help? thanks for any help that i get

Answer 1

I don't know if you are using navigation controller during the transition between screens. But I suppose you are using it. So let's say you have two ViewController. FirstViewController and SecondViewController. And they are also using navigation controller when you make a transition from FirstViewController to the SecondViewController. In the SecondViewController you have your tableView and when you click a row in that tableView you want to send some value to the FirstViewController before dismiss. Add this function in the SecondViewController and call it before dismiss :
func changeValue(myValue : Bool) {
if let navController = SecondViewController as? UINavigationController {
let getfirstVC = navController.topViewController as! FirstViewController
getfirstVC.chosenDaily = myValue
}
}
and your tableview function will be like this :
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let viewController: UIViewController = UIViewController()
switch (indexPath.row) {
case 0:
print("hello")
changeValue(true)
dismiss(animated: true, completion: nil)
Don't forget to change FirstViewController and SecondViewController according to your own.

Answer 2

You can use Delegate to interactive between view.
protocol tableViewControllerDelegate {
func change(value:Bool)
}
class tableViewController: UIViewController {
var del:tableViewControllerDelegate!
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
switch (indexPath.row) {
case 0:
del?.change(value:true)
dismiss(animated: true, completion: nil)
break;
default:
break
}
}
}
Class is reference type, You can also processing data by class.
class AddViewController:UIViewController,tableViewControllerDelegate{
var chosenDaily = false
func change(value:Bool){
chosenDaily = value
}
}
class tableViewController: UIViewController {
var data:Sample!
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
switch (indexPath.row) {
case 0:
data?.chosenDaily = true
dismiss(animated: true, completion: nil)
break;
default:
break
}
}
}
class Sample{
var chosenDaily = false
}
class AddViewController:UIViewController{
var data = Sample()
func open(){
let view = tableViewController()
view.data = data
}
}