Fatal Error: Index out of range - Swift 4 and Firebase - swift

Question

I am creating an iOS application using XCode 8 and Swift 4 that keeps track of events. I am using Firebase as my database tool for this app. I am running into an "index out of range" error in the code below. I am using a for loop to read the Event start and end times for each event in the Firebase Database. The code is able to return the event names, but not the times underneath. Why is this the case? Is there something wrong with my code, or is there something wrong with my database structure? The database structure used is pasted below the code here.
Code here:
import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase
class Event_List_Controller: UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var tableView: UITableView!
var eventList = [String]()
var startTimeArray = [String]()
var endTimeArray = [String]()
var ref: DatabaseReference?
var handle:DatabaseHandle?
override func viewDidLoad() {
super.viewDidLoad()
endTimeArray.removeAll()
tableView.delegate = self
tableView.dataSource = self
let emailfinal = UserDefaults.standard.string(forKey: "splicedEmailStandard")
ref = Database.database().reference()
handle = ref?.child(emailfinal!).child("Event Data").observe(.childAdded, with: { (snapshot) in
if let item = snapshot.value as? String {
self.eventList.append(item)
self.tableView.reloadData()
}
})
// FOR LOOP THAT POPULATES THE START AND END TIMES
for individualEvents in eventList {
ref = Database.database().reference()
handle = ref?.child(emailfinal!).child("Event Data").child(individualEvents).child("Start Time").observe(.childAdded, with: { (snapshot) in
if let item = snapshot.value as? String {
self.startTimeArray.append("\(item)")
}
})
handle = ref?.child(emailfinal!).child("Event Data").child(individualEvents).child("End Time").observe(.childAdded, with: { (snapshot) in
if let item = snapshot.value as? String {
self.endTimeArray.append("\(item)")
}
})
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return eventList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCell(withIdentifier: "customClassCell") as! CustomTableViewCell
cell.classLabel.text = eventList[indexPath.row]
// FATAL ERROR: INDEX OUT OF RANGE HERE.
cell.timeLabel.text = "\(startTimeArray[indexPath.row]) - \(endTimeArray[indexPath.row])"
return cell
}
}
Database Structure:
email#email (User)
-> User Information
----> (Information)
---> Event Information
------> Event Name
----------> Event Start Time
----------> Event End Time
----------> Event Location
email#email (User 2)
----> ...

Answer 1

It looks like you're calling reloadData() before you're actually getting the start and end times for the events, so the startTimeArray and endTimeArray will not have objects at the index of the event you just got from firebase.
Also consider that with Firebase you're setting up observing rather than getting all of your data at once. Perhaps some simple class like Event:
class Event {
var name: String
var startTime: String
var endTime: String
init(name: String) {
self.name = name
self.startTime = "" //or some other sensible default before loading
self.endTime = "" //or some other default
}
}
Then have an array of Event object that your tableview is using instead of the array of strings, and update the Event objects and refresh the table view whenever you get new data in from Firebase