How to create custom cells 100% programmatically in Swift? - ios

Question

I am trying to build a TableView programmatically, but I cannot get a basic standard label to display; all I see is basic empty cells. Here's my code:
TableView Cell:
class TableCell: UITableViewCell {
let cellView: UIView = {
let view = UIView()
view.backgroundColor = .systemRed
return view
}()
let labelView: UILabel = {
let label = UILabel()
label.text = "Cell 1"
return label
}()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
setup()
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setup() {
addSubview(cellView)
NSLayoutConstraint.activate([
cellView.topAnchor.constraint(equalTo: topAnchor),
cellView.bottomAnchor.constraint(equalTo: bottomAnchor),
cellView.leadingAnchor.constraint(equalTo: leadingAnchor),
cellView.trailingAnchor.constraint(equalTo: trailingAnchor)])
cellView.addSubview(labelView)
}
}
Data Source:
class TableDataSource: NSObject, UITableViewDataSource {
let cellID = "cell"
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 5
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellID, for: indexPath) as! TableCell
return cell
}
}
And this is the VC:
class TableViewController: UITableViewController {
let dataSource = TableDataSource()
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(TableCell.self, forCellReuseIdentifier: dataSource.cellID)
tableView.dataSource = dataSource
}
}
I am trying to keep the code as basic as possible for future references. I've set various breakpoints to see what could go wrong, but they all check out. Could it be the constraints that are wrong?
Any help is appreciated.

Answer 1

I see several errors in your cell.
Add subviews to contentView, not directly to cell:
contentView.addSubview(cellView)
cellView.addSubview(labelView)
The same is necessary for constraints:
NSLayoutConstraint.activate([
cellView.topAnchor.constraint(equalTo: contentView.topAnchor),
cellView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
cellView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
cellView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor)
])
Views created in code need to set translatesAutoresizingMaskIntoConstraints = false,
let cellView: UIView = {
let view = UIView()
view.backgroundColor = .systemRed
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
let labelView: UILabel = {
let label = UILabel()
label.text = "Cell 1"
label.translatesAutoresizingMaskIntoConstraints = false
return label
}()
There are no constraints for your label.

Answer 2

Your constraints don't work, because you need to change translatesAutoresizingMaskIntoConstraints for cellView in your setup():
func setup() {
addSubview(cellView)
cellView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
cellView.topAnchor.constraint(equalTo: topAnchor),
cellView.bottomAnchor.constraint(equalTo: bottomAnchor),
cellView.leadingAnchor.constraint(equalTo: leadingAnchor),
cellView.trailingAnchor.constraint(equalTo: trailingAnchor)])
cellView.addSubview(labelView)
}