Add UIView To Tableview cell not updating - swift

Question

I am trying to add a UIView to an existing IBOutlet in a tableview cell. However this does not appear until I have scrolled away from the cell and scroll back to it.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let stockCell = tableView.dequeueReusableCell(withIdentifier: "stockCell", for: indexPath) as! customStockCell
let progressBar = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
progressBar.backgroundColor = .green
stockCell.progressContainerView.addSubview(progressBar)
return cell
}
class customStockCell: UITableViewCell {
#IBOutlet var progressContainerView: UIView!
}

Answer 1

Using contentView instead of containerView works fine for me.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let stockCell = tableView.dequeueReusableCell(withIdentifier: "stockCell", for: indexPath)
let progressBar = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
progressBar.backgroundColor = .green
stockCell.containerView.addSubview(progressBar)
return cell
}
You can also create a custom cell class and add this logic inside its' initialiser.
Alternatively, if the above solution doesn't work, you can add this logic inside willDisplayCell:
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
let progressBar = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
progressBar.backgroundColor = .green
cell.containerView.addSubview(progressBar)
}