Updating navigation in Viewcontrollers - Coredats - swift

Question

I am a new programmer using Swift.
In my project I am using coredata, and a lot of view controllers.
I have this view controllers:
Viewcontroller1 has my home Viewcontroller (VC1).
Viewcontroller2 (VC2), with a list of items reloaded from my coredata (in a table view).
Viewcontroller2 (VC3), lists the attributes of the selected item in VC2.
Viewcontroller2 (VC4), makes the user edit the attributes of selected item in VC2.
SO this is my navigation: VC1 -> VC2 -> VC3 -> VC4.
The problem:
Lets say I am in VC1 and go to VC2.
I now choose an item from view controller and it takes me to VC3 (I push VC3).
I am now in the item characteristics. which are listed from coredata.
To edit them I made a button, with a segue, VC4, where I made a view where the user can change the values of the choosen item. Once the user introduces any changes in the text fields, I do a NSFetchRequest, and update the values like this:
#IBAction func saveButton(_ sender: UIBarButtonItem) {
let app = UIApplication.shared.delegate as! AppDelegate
let context = app.persistentContainer.viewContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Simulator")
do {
let results = try context.fetch(request)
if results.count > 0 {
for result in results as! [NSManagedObject] {
result.setValue(designLabel.text, forKey: "designation")
result.setValue(typeLabel.text, forKey: "type")
result.setValue(localLabel.text, forKey: "local")
do {
try context.save()
} catch {
print("Error updating")
}
}
}
} catch {
print ("Error")
}
_ = self.navigationController?.popViewController(animated: true)
}
So now, by pressing saveButton I update local, designation and type atributes, and than pop VC3.
Now in VC3 I expected to receive the update values. Instead I am receiving the old values. This is what I have in VC3:
override func viewWillAppear(_ animated: Bool) {
super.viewDidAppear(animated)
map.delegate = self
let fetchRequest:NSFetchRequest<Simulator> = Simulator.fetchRequest()
do{
let searchResults = try DatabaseController.getContext().fetch(fetchRequest)
for result in searchResults as [Simulator]{
if (String(describing: result.objectID) == choosenID)
{
self.title = result.designation
localLabel.text = "Local: \(result.local!)"
typeLabel.text = "Type: \(result.type!)
print("I found it") //to check if I go inside this = and I go inside (true)
{
}
}
catch{
print("Error: \(error)")
}
}
}
Now I press the back button and I go to VC2: some thing. The cell, which have the designation on a label still don't updated it.
So I go to VC! using back button.
Now If I move forward to VC2 or VC3 everything Is updated.
What it's happening? Why isn't it updating when I pop from VC4 to VC3?

Answer 1

When you go back you are going back to the view as it was, when you go forward you are reloading it. What you can do though is reload the data when you go back.