Pass data from the first VC to the third (Swift) - ios

Question

I have 3 viewControllers and i'm passing data from the first to the second in this way (this is the first VC)
var steppers : UIStepper?
#IBOutlet weak var hourLabel: UILabel!
#IBOutlet weak var stepper: UIStepper!
#IBAction func stepper(_ sender: UIStepper) {
hourLabel.text = String(sender.value)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let nc = segue.destination as? SelectClass {
nc.limit = Int(stepper.value)
} }
in the second VC i have the var limit = 0. Till here everything works well but what i want to do is to pass the value that the user gives to the stepper to the third VC. I tried to create another variable in the third VC var limit2 = 0and to pass the data in this way from the secondo VC to the third
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let vc = segue.destination as? ThirdClass {
vc.limit2 = limit
} }
but without results, my var limit2 = 0it always has the value 0 instead of taking the value that i added with the stepper. How can i do?
this is the prepare in the second VC
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == nearbySearchSegueIdentifier {
guard let category = sender as? QCategoryy else {
return
}
if let selectedRows = tableView.indexPathsForSelectedRows {
if let vc = segue.destination as? ThirdClass {
vc.category = category
vc.limit2 = limit
}
}
}
}

Answer 1

Considering your current code, its possible that limit2 its not set because this condition is not valid:
// This condition could be failing sometimes
if let selectedRows = tableView.indexPathsForSelectedRows {
if let vc = segue.destination as? ThirdClass {
vc.category = category
vc.limit2 = limit
}
}
According to the Documentation, indexPathsForSelectedRows returns an optional and in your segue, you are only setting limit2 if that value is not nil.
Try to set limit2 outside any condition, so it will be executed always and if you need to fulfill a condition in order to do a segue, check shouldPerformSegue(withIdentifier:sender:) here.
Also, if the value that you need on VC3 is the same that you have when you leave VC1, there are different approaches that you could use to pass the data between them without having to rely on VC2.
One could be to create a static variable in VC1 and set the limit value before pushing to VC2:
var steppers : UIStepper?
#IBOutlet weak var hourLabel: UILabel!
#IBOutlet weak var stepper: UIStepper!
// ADD THIS
static var globalLimit: Int = 0
#IBAction func stepper(_ sender: UIStepper) {
hourLabel.text = String(sender.value)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let nc = segue.destination as? SelectClass {
nc.limit = Int(stepper.value)
// AND THIS
VC1ClassName.globalLimit = Int(stepper.value)
}
}
Then inside VC3 load your global value whenever you want (maybe viewDidLoad):
override func viewDidLoad() {
super.viewDidLoad()
limit2 = VC1ClassName.globalLimit
}
Instead of having data passing through ViewControllers, you could also create a StepperManager class or something similar that is responsible for managing the data and you can access it from every class you need at any moment in time.

Answer 2

Why don't you just pass if from First to Second to Third?
FirstVC:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "tosecondsegue" {
let itemController : Second = segue.destination as! Second
itemController.limit = 0 //Whatever you want
}
}
SecondVC:
var limit = 0
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "tothirdsegue" {
let itemController : ThirdVC = segue.destination as! ThirdVC
itemController.limit2 = limit
}
}
ThirdVC:
var limit2 = 0
//Use it here now