How can I make a variable inside a function global? - ios

Question

I currently have the following function called saveRun()
func saveRun() {
let startLoc = locations[0]
let endLoc = locations[locations.count - 1]
let startLat = startLoc.coordinate.latitude
let startLong = startLoc.coordinate.longitude
let endLat = endLoc.coordinate.latitude
let endLong = endLoc.coordinate.longitude
//1. Create the alert controller
let alert = UIAlertController(title: "Save the Run", message: "Choose a name: ", preferredStyle: .alert)
//2. Add the text field
alert.addTextField { (textField) in
textField.text = ""
}
// 3. Grab the value from the text field, and print it when the user clicks OK
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { [weak alert] (_) in
let textField = alert?.textFields![0] // Force unwrapping because we know it exists.
// Create name for run
let runName = textField?.text
let run = self.databaseRef.child(runName!)
let user = FIRAuth.auth()?.currentUser?.uid
// Enter run info into db
run.child("startLat").setValue(startLat)
run.child("startLong").setValue(startLong)
run.child("endLat").setValue(endLat)
run.child("endLong").setValue(endLong)
run.child("distance").setValue(self.distance)
run.child("time").setValue(self.seconds)
run.child("user").setValue(user)
// Enter locations into db
var i = 0
for location in self.locations {
run.child("locations").child("\(i)").child("lat").setValue(location.coordinate.latitude)
run.child("locations").child("\(i)").child("long").setValue(location.coordinate.longitude)
i = i + 1
self.performSegue(withIdentifier: DetailSegueName, sender: nil)
}
}))
// 4. Present the alert
self.present(alert, animated: true, completion: nil)
}
My problem is that I am trying to extract 'runName' from the action that I am adding when the user clicks 'Ok' on the alert controller and using it in the following function:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let detailViewController = segue.destination as? DetailViewController {
detailViewController.runName = self.runName
}
}
When I try to print 'runName' in DetailViewController, the value of runName is nil. The issue I think is that I cannot set a global variable inside the action I have added as it is in a function. Is there any other way I can obtain this variable's value and use it outside of the function?

Answer 1

Class YourClassName:UIViewController {
var runName:String = "" // This will be global for your class
//Remove local decalration of runName variable
func saveRun() { // your function
alert.addAction(
//.....
self.runName = textfield?.text
)
}
}
Now you can use in whole class.

Answer 2

I solved this thanks to #DSDharma pointing out that even if 'runName' was set as a global variable, using it as a global variable inside of an alert function block required the 'self' keyword.
For example, before I had the following inside of the alert function block:
let runName = textField?.text
This needed to be changed to:
self.runName = textField?.text