Passing global Arrays through functions is not working in swift - arrays

Question

I have this program which takes values from firestore and puts them in an array. I have confirmed that these arrays have data inside of them by using test print functions. When I declare 2 global arrays ( gloabalGPA and globalSAT) and pass the value of the gpaColleges and the satColleges into them through a function everything works. I placed test print functions inside of the functions (the swithcSATArray and the switchGPAArray). However when I attempt to print these global variables again in a different function the print function prints out an empty array. like so: ( [] )
import UIKit
import FirebaseAuth
import FirebaseDatabase
import Firebase
import FirebaseFirestore
class ScoresViewController: UIViewController {
var docRef: DocumentReference!
let defaultStore = Firestore.firestore()
var globalGPA = [String]()
var globalSAT = [String]()
override func viewDidLoad() {
super.viewDidLoad()
let userID: String = (Auth.auth().currentUser?.uid)!
docRef = Firestore.firestore().document("Users/\(userID)")
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBOutlet weak var GpaScore: UITextField!
#IBOutlet weak var SATscore: UITextField!
#IBOutlet weak var ACT_Score: UITextField!
#IBAction func SubmitTapped(_ sender: Any) {
print("Submit Tapped")
let Sattext = SATscore.text
let Acttext = ACT_Score.text
let Gpatext = GpaScore.text
let gpaScore = Gpatext
let SatScore2 = Sattext
let Acttext2 = Acttext
let CombinedScores = Sattext! + Acttext!
if GpaScore.text == "" {
self.createAlert(titleText: "Error", messageText: "No Weighted GPA Entered")
}
else if CombinedScores == "" {
self.createAlert(titleText: "Error", messageText: "No SAT nor ACT Score Entered")
}
else{
let dataToSave: [String: Any] = ["GPA": gpaScore!, "SAT Score": SatScore2!, "ACT Score": Acttext2!]
docRef.setData(dataToSave) { (error) in
if let error = error {
print("error in sending data to fireStore: \(error.localizedDescription)")
}else {
print("Data was succesfully saved to FireStore")
}
}
self.presentLoggedInScreen()
sendToFireStore(gpa: gpaScore!, sat: SatScore2!)
self.addArrays()
}
}
func createAlert (titleText : String , messageText: String) {
let alert = UIAlertController (title: titleText, message: messageText, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Dissmis", style: .default, handler: { (action) in alert.dismiss(animated: true, completion: nil)
}))
self.present(alert, animated: true, completion: nil)
}
func presentLoggedInScreen() {
let storyboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let HomeVC:HomeVC = storyboard.instantiateViewController(withIdentifier: "HomeVC") as! HomeVC
self.present(HomeVC, animated: true, completion: nil)
}
func sendToFireStore(gpa: String, sat: String) {
let db = Firestore.firestore()
var gpaColleges = [String]()
let gpaRef = db.collection("Colleges")
let query1 = gpaRef
.whereField("Average GPA", isLessThanOrEqualTo: gpa)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
gpaColleges.append(document.documentID)
}
self.switchGPAArray(gpa: gpaColleges)
}
}
var satColleges = [String]()
let satRef = db.collection("Colleges")
let query2 = satRef
.whereField("Average SAT Score", isLessThanOrEqualTo: sat)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
satColleges.append(document.documentID)
}
self.swithcSATArray(sat: satColleges)
}
}
}
func swithcSATArray(sat: Array<Any>) {
self.globalSAT = sat as! [String]
print("Printing inside of SAT function \(self.globalSAT)")
}
func switchGPAArray(gpa: Array<Any>) {
self.globalGPA = gpa as! [String]
print("Printing inside of GPA funtion \(self.globalGPA)")
}
func addArrays() {
print("INSIDE OF ADD ARRAYS SAT \(self.globalSAT)")
print("INSIDE OF ADD ARRAYS GPA \(self.globalSAT)")
}
}
Any help would be greatly appreciated.

Answer 1

First of all there is lot of code but little information about your problem. We don't even know which function you call first and what is the second one that prints empty?
I can edit this answer after you provide more details. But as far as I see, you have closures and the compiler won't wait closure to complete, to run the next line. If this is the problem you can use threads and run your code in main thread so you can be sure it is completed. Or you can use delegate pattern to be notified when it's complete.
Or just do this:
let dataToSave: [String: Any] = ["GPA": gpaScore!, "SAT Score": SatScore2!, "ACT Score": Acttext2!]
docRef.setData(dataToSave) { (error) in
if let error = error {
print("error in sending data to fireStore: \(error.localizedDescription)")
}else {
self.presentLoggedInScreen()
sendToFireStore(gpa: gpaScore!, sat: SatScore2!)
self.addArrays()
print("Data was succesfully saved to FireStore")
}
}
If no one above works, provide more details about your issue! :)