Can't get label text to update swift - ios

Question

There is a label on my ProductViewController called idLabel that I am trying to update. Here is the VC that sends the info. At one point I had the text updating when you press the playThis button and the label would change from the stock label text to nothing so I know something is happening but now that it is in the viewDidLoad it just shows nothing. How do I make it show the text on my receiving end?
here is the sending VC:
import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase
import FirebaseStorage
class ListViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableViewProducts: UITableView!
var delegate: ListViewController?
var ref:DatabaseReference?
var databaseHandle: DatabaseHandle?
var postData = [String]()
override func viewDidLoad() {
super.viewDidLoad()
ref = Database.database().reference()
databaseHandle = ref?.child("0").observe(.childAdded, with: { (snapShot) in
let post = snapShot.value as? String
if let actualPost = post {
self.postData.append(actualPost)
self.tableViewProducts.reloadData()
}
})
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(postData)
return postData.count
}
//This places the text on the ViewControllerTableViewCell which does show up
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")
cell?.textLabel?.text = postData[indexPath.row]
cell?.textLabel?.textColor = UIColor.white
return cell!
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "showDetails", sender: self)
}
//This code is what sends the text data elswhere
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? ProductViewController {
destination.updater?.id = postData[(tableViewProducts.indexPathForSelectedRow?.row)!]
}
}
}
Here is the ProductViewController:
import UIKit
import AVFoundation
import Firebase
class ProductViewController: UIViewController {
#IBOutlet weak var imageView: UIImageView!
#IBOutlet weak var idLabel: UILabel!
var passStuff: productsList?
var updater: productsList?
override func viewDidLoad() {
super.viewDidLoad()
idLabel.text = updater?.id
}
var player : AVPlayer!
let url = "http://listen.shoutcast.com/radiodeltalebanon"
#IBAction func playThis(_ sender: Any) {
print("Something is playing")
}
#IBAction func pauseBtn(_ sender: Any) {
player.pause()
}
}

Answer 1

If you just planning to pass the id instead of an object then use a simple variable.
Your code in prepare for segue then becomes
destination.variable = id_to_pass.
Now you got the id in the ProductViewController you can update it in viewdidload

Answer 2

Problem in the setting value of updater from ListViewController
You are setting the value to a object which is not been initialised yet.
//This code is what sends the text data elswhere
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? ProductViewController {
destination.updater?.id = postData[(tableViewProducts.indexPathForSelectedRow?.row)!]
}
}
Update the code in the following way
//This code is what sends the text data elswhere
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? ProductViewController,
let index = tableViewProducts.indexPathForSelectedRow?.row {
// Check whether postData array count is greater than index
let updaterId = postData.count > index ? postData[index] : ""
// Initialize "productsList" instance and assign the id value and sent this object to next view controller
var updater = productsList()
updater.id = updaterId
destination.updater = updater
}
}