Swift: Textviews within UIStackView not displaying - swift

Question

I'm trying to create a basic table that would have 4 columns. I'm approaching this by creating a UITableView with a custom cell which contains a horizontal stack view containing the required text views. Here is my UITableView code:
import UIKit
class HistoryTableViewController: UITableViewController {
let cellID = "HistoryColumns"
struct CellData {
let firstColumn: String?
let secondColumn: String?
let thirdColumn: String?
let fourthColumn: String?
}
var data = [CellData]()
override func viewDidLoad() {
super.viewDidLoad()
data = [CellData.init(firstColumn: "Date", secondColumn: "Flight number", thirdColumn: "Type", fourthColumn: "Pre-refuel FOB (kg)")]
tableView.register(FuelHistoryColumnCells.self, forCellReuseIdentifier: cellID)
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return data.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellID) as! FuelHistoryColumnCells
cell.firstColumn = data[indexPath.row].firstColumn
cell.secondColumn = data[indexPath.row].secondColumn
cell.thirdColumn = data[indexPath.row].thirdColumn
cell.fourthColumn = data[indexPath.row].fourthColumn
return cell
}
}
And this is my custom cell code:
import UIKit
class FuelHistoryColumnCells: UITableViewCell {
var firstColumn: String?
var secondColumn: String?
var thirdColumn: String?
var fourthColumn: String?
lazy var firstColumnView: UITextView = {
let textView = UITextView()
textView.font = UIFont.systemFont(ofSize: 15)
textView.backgroundColor = .green
return textView
}()
lazy var secondColumnView: UITextView = {
let textView = UITextView()
textView.font = UIFont.systemFont(ofSize: 15)
textView.backgroundColor = .green
return textView
}()
lazy var thirdColumnView: UITextView = {
let textView = UITextView()
textView.font = UIFont.systemFont(ofSize: 15)
textView.backgroundColor = .green
return textView
}()
lazy var fourthColumnView: UITextView = {
let textView = UITextView()
textView.font = UIFont.systemFont(ofSize: 15)
textView.backgroundColor = .green
return textView
}()
lazy var fifthColumnView: UITextView = {
let textView = UITextView()
textView.font = UIFont.systemFont(ofSize: 15)
textView.backgroundColor = .green
return textView
}()
lazy var stackView: UIStackView = {
let stack = UIStackView(arrangedSubviews: [firstColumnView, secondColumnView, thirdColumnView, fourthColumnView])
stack.axis = .horizontal
stack.distribution = .fillEqually
return stack
}()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
addSubview(stackView)
}
override func layoutSubviews() {
super.layoutSubviews()
if let firstColumn = firstColumn {
firstColumnView.text = firstColumn
}
if let secondColumn = secondColumn {
secondColumnView.text = secondColumn
}
if let thirdColumn = thirdColumn {
thirdColumnView.text = thirdColumn
}
if let fourthColumn = fourthColumn {
fourthColumnView.text = fourthColumn
}
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I'm sure I'm missing something obvious here as nothing is showing up on the table view...