Firebase Clients App - ios

Question

I was making an app for one of my family members so that they could better manage their clients but ran into some issues. This is my first time using Firebase and I just can't seem to get my code to work! The part in which I am getting stuck involves Firebase's Realtime Database, and I am working in XCode 8.3 with Swift 3.1.
Code:
import UIKit
import FirebaseCore
import FirebaseDatabase
import FirebaseAuth
var specClientId = ""
class MyCell: UITableViewCell {
#IBOutlet var nameCell: UILabel!
#IBOutlet var statusCell: UILabel!
}
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet var tableView: UITableView!
var ref: FIRDatabaseReference!
var tableArray: [String] = []
var clientId: [String] = []
var statusArray:[String] = []
#IBAction func signOut(_ sender: Any) {
UserDefaults.resetStandardUserDefaults()
performSegue(withIdentifier: "segueBackLogin", sender: self)
}
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return tableArray.count
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CellFront") as! MyCell
cell.nameCell.text = tableArray[indexPath.row]
cell.statusCell.text = statusArray[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
specClientId = clientId[indexPath.row]
ref.child("Users").child(specClientId).child("lastUpdate").removeValue()
performSegue(withIdentifier: "segue", sender: self)
}
override func viewDidLoad() {
super.viewDidLoad()
if FIRApp.defaultApp() == nil {
FIRApp.configure()
}
ref = FIRDatabase.database().reference()
ref.child("Users").observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let specificValues = value?.allKeys
self.tableArray.removeAll()
self.statusArray.removeAll()
self.clientId.removeAll()
var it = 0
for Uservalue in specificValues! {
self.tableArray.append("")
self.statusArray.append("")
self.clientId.append(Uservalue as! String)
self.ref.child("Users")
.child(Uservalue as! String)
.child("name")
.observeSingleEvent(of: .value, with: { (snapshot) in
let nameValue = snapshot.value as? String
self.tableArray.insert(nameValue!, at: it)
self.tableArray = self.tableArray.filter {$0 != ""}
self.tableView.reloadData()
}) { (error) in
print(error.localizedDescription)
}
self.ref.child("Users")
.child(Uservalue as! String)
.child("lastUpdate")
.observeSingleEvent(of: .value, with: { (snapshot) in
if let nameValue = snapshot.value as? String {
self.statusArray.insert("*", at: it)
self.tableView.reloadData()
} else {
self.statusArray.insert("", at: it)
self.tableView.reloadData()
}
}) { (error) in
print(error.localizedDescription)
}
it += 1
}
}) { (error) in
print(error.localizedDescription)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
My main issue is that when I get the user's name and their lastUpdate status, the array lists do not match up correctly and the TableView displays the wrong information in terms of which User has submitted their updates. To fix this issue, I tried to use the insert method in my arrays but now the app crashes. Previously, I was using the append method but that leads to the wrong information being displayed in the TableView. I would appreciate it if any of you could help me with this issue.
Note: The App Crashes due to the StatusArray not having the same amount of elements as the TableArray. This is caused by the TableArray having some empty elements with no names in them.
Thanks,
KPS
Edit 1:
for Uservalue in specificValues! {
self.clientId.append(Uservalue as! String)
let user = User()
self.ref.child("Users")
.child(Uservalue as! String)
.observeSingleEvent(of: .value, with: { (snapshot) in
let nameValue = snapshot.value as? NSDictionary
let specNameValue = nameValue?.allKeys
var i = 0
while i < specNameValue!.count {
if specNameValue?[i] as? String == "name" {
user.name = nameValue?.allValues[i] as! String
} else if specNameValue?[i] as? String == "lastUpdate" {
user.status = "*"
} else if specNameValue?[i] as? String != "name" && specNameValue?[i] as? String != "lastUpdate" && specNameValue?[i] as? String != "message" && specNameValue?[i] as? String != "adminMessage" && specNameValue?[i] as? String != "photoURL" {
user.status = ""
}
i += 1
}
}) { (error) in
print(error.localizedDescription)
}
self.tableArray.append(user)
self.tableView.reloadData()
}

Answer 1

The main reason your app is crashing is because in your cell for row you are reloading after loading the first user and the cell expects the statusArray to have elements already.
cell.nameCell.text = tableArray[indexPath.row]
cell.statusCell.text = statusArray[indexPath.row] // fails here I assume
There a few issues going on here that I'll try to address.
You are reloading the table immediately for each child that is iterated through. It would be smart to append elements to each array then once completed display all elements by calling tableView.reloadData()
Are status' independent of the name that you are expecting? If the data is correlated, it would be smart to create a simple Object to house this data and have a single array of data that the tableView will use for it's dataSource
Once your data is fully loaded, you could sort the data accordingly then reload the datasource to solve the issue of pulling data from the server that is out of order. This is why the append(element: ) is simple and useful
Hopefully this helps! It may seem like a bit more work but it would definitely be beneficial to performance, organization and readability for yourself.