Cannot Pass Data between TableViewControllers - ios

Question

Merry Christmas! I am currently making a "reminders" app at the moment. My "secondary" TableViews fail to pass data back into the "main" TableView. (please see image below). I need the data to pass back into the "main" TableView so that I can save it and display that into another TableView, so the user can see the tasks they have put in.
The code inside the IconTableViewController (and ShowTableViewController):
var userImage: String = ""
var userTitle: String = ""
var userDesc: String = ""
var frequency: String = ""
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let navigationViewController = segue.destination as? UINavigationController {
guard let viewController = navigationViewController.topViewController as? NewItemTableViewController else { return }
let userImageNew = userImage
let userTitleOld = userTitle
let userDescOld = userDesc
let frequencyOld = frequency
viewController.selectedImage = userImageNew
viewController.userTitle = userTitleOld
viewController.userDesc = userDescOld
viewController.selectedFrequency = frequencyOld
}
}
The code inside NewItemTableViewController:
var selectedImage: String = ""
var selectedFrequency: String = ""
var userTitle: String = ""
var userDesc: String = ""
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showSelect" {
let userImageOld = selectedImage
let userTitleNew = titleTextField.text
let userDescNew = descTextView.text
let frequencyOld = selectedFrequency
let viewController = segue.destination as! ShowTableViewController
viewController.userImage = userImageOld
viewController.userTitle = userTitleNew!
viewController.userDesc = userDescNew!
viewController.frequency = frequencyOld
}
if segue.identifier == "iconSelect" {
let userImageOld = selectedImage
let userTitleNew = titleTextField.text
let userDescNew = descTextView.text
let frequencyOld = selectedFrequency
let viewController = segue.destination as! IconTableViewController
viewController.userImage = userImageOld
viewController.userTitle = userTitleNew!
viewController.userDesc = userDescNew!
viewController.frequency = frequencyOld
}
}
Thank you very much for your help!

Answer 1

Seems like NewItemTableViewControlleris not yet top viewController on the navigation stack. Try accessing it in the same trivial way,
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let viewController = segue.destination as? NewItemTableViewController {
let userImageNew = userImage
let userTitleOld = userTitle
let userDescOld = userDesc
let frequencyOld = frequency
viewController.selectedImage = userImageNew
viewController.userTitle = userTitleOld
viewController.userDesc = userDescOld
viewController.selectedFrequency = frequencyOld
}
}
You should put a breakpoint inside above method prepare(for segue and see if it is being called. Because i feel you don't have unwind segue as these viewControllers are just pushed on the navigation stack. So in that case you can also use viewWillDisappear to set the data by accessing NewItemTableViewController from the navigation stack. Something as below,
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if let vc = self.navigationController?.viewControllers.first(where: { $0 is NewItemTableViewController }) as? NewItemTableViewController {
// Set data.
}
}

Answer 2

You should use Delegate to push data back to NewItemTableViewController. You can refer this thread: Pass data back to previous viewcontrolle