Swift property nil outside unwindToViewController - ios

Question

To pass data between views, I decided to use a "temporary" object that would act as the data model of my views.
var tempMedecine = TempMedecine()
var xValue = 0
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let dmController = segue.destinationViewController as? JRBDosageMainTableViewController {
dmController.tempMedecine = self.tempMedecine
}
}
#IBAction func unwindToViewController(segue: UIStoryboardSegue) {
if let dosageController = segue.sourceViewController as? JRBDosageMainTableViewController {
self.tempMedecine = dosageController.tempMedecine!
self.xValue = 10
let dosageCell = tableView.cellForRowAtIndexPath(NSIndexPath(forRow: 1, inSection: 0))
dosageCell?.detailTextLabel?.text = String(self.tempMedecine.dosageQuantity!) + " " + self.tempMedecine.dosageQuantityType!
}
}
override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {
if identifier == "saveMedecine" {
print(xValue)
guard tempMedecine.name != nil else {
Common.genericAlertController(self, title: "Error", message: "You need to define a name", preferedStyle: .Alert)
return false
}
guard self.tempMedecine.dosageQuantityType != nil else {
Common.genericAlertController(self, title: "Error", message: "You need to set a quantity", preferedStyle: .Alert)
return false
}
}
else {
return true
}
return false
}
This is some of my code from the "index" viewController where I need to tackle validation.
As you can see all of my viewControllers have a property named tempMedecine. I pass it around and update the data if needed.
The problem is that self.tempMedecine.dosageQuantityType returns nil in the shouldPerformSegueWithIdentifier method but isn't returning nil in the unwindToViewController method.
I figured there could be two instances of my TempMedecine object, but that's not the case. I also thought there might be a problem with the way I pass the tempMedecine variable between my viewControllers but the property tempMedecine.name is effectively transfered, the only difference is that this property is set in the same viewController where I want to implement validation :
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
self.tempMedecine.name = textField.text
return true
}
It's really looking like I'm working with two different scope. As soon as I leave the unwindToViewController method, I would get back to another scope where the tempMedecine variable isn't updated.
But the weird part is when I use a simple variable like xValue. If I update its value in the unwindToViewController method I get the correct value in shouldPerformSegueWithIdentifier
What am I missing? Thanks for your help.

Answer 1

Okay, I fixed it. What happened was that I implemented some code to reset the dataSource which is tempMedecine if the user decided to click on the Back Button in the navigation bar :
if self.isMovingToParentViewController() {
tempMedecine?.dosageQuantity = nil
tempMedecine?.dosageQuantityType = nil
}
The thing is, I never thought the issue could come from this as I can use the tempMedecine data to set the value in my tableView after unwinding to the index viewController but I totally missed the part when object are passed my reference.