title: Firestore - UISlider inside UITableViewCell
body: <p>I have a UISlider inside custom cells of a tableView. In the cell there is also a UILabel displaying the sliders value. At the moment I have got it so that I can update the sliders value to firestore and also into the label. However when I go off the screen/app and load the screen again, I can't load the previous sliders value into the slider. I still can update the sliders value and it will still transfer to firestore and everything works well. I have tried loading the value from firestore into the slider when the screen is first launched, which works perfectly, but It doesn't let me update the slider onscreen when I do this, but it does update on firestore. What would be perfect is so that the data is loaded from firestore when the screen is first loaded, I can then update the slider and it will work on the app and in firestore. Any help would be greatly appreciated! Many thanks!!  </p>
  
  <p><strong>ViewController</strong></p>
  
  <pre><code>func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -&gt; UITableViewCell {
      let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
  
      cell.slider.tag = indexPath.row
      cell.slider.addTarget(self, action: #selector(ViewController.sliderChange(sender:)), for: .valueChanged)
  
      cell.sliderLabel.text = String(Int(cell.slider.value))
  
      // code that loads values when screen is first launched but then doesn't let me update the onscreen values
      cell.slider.value = Float(array[indexPath.row].number)
  
      return cell
  }
  
   @objc func sliderChange(sender: UISlider) {
      let currentValue = Int(sender.value)
      let row = sender.tag
      let Id = array[row].documentID
  
      let userRef = db.collection("Users").document(user!)
      userRef.collection("Friends").document(Id).updateData(["number" : currentValue]) {
          error in
          if let error = error {
              print("Error adding document: \(error.localizedDescription)")
          } else {
              print(currentValue)
          }
      }
  
      self.tableView.reloadData()
  
  }
  </code></pre>
  
  <p><strong>TableViewCell</strong></p>
  
  <pre><code>class TableViewCell: UITableViewCell {
  
  @IBOutlet weak var sliderLabel: UILabel!
  @IBOutlet weak var slider: UISlider!
  
  override func awakeFromNib() {
      super.awakeFromNib()
      // Initialization code
  
  }
  
  override func setSelected(_ selected: Bool, animated: Bool) {
      super.setSelected(selected, animated: animated)
  
      // Configure the view for the selected state
  }
  </code></pre>