AutoLayout in UITableViewCell contentView

Question

I'm trying to programmatically create constraints to center this pink UIView in a UITableViewCell. However, when I add the constraints, they don't apply and I get a message in the console that says that some NSAutoresizingMaskLayoutConstraints can't be simultaneously satisfied.

So when I set cell.contentView.translatesAutoresizingMaskIntoConstraints = false, I get this message in the console :

"Changing the translatesAutoresizingMaskIntoConstraints property of the contentView of a UITableViewCell is not supported and will result in undefined behavior, as this property is managed by the owning UITableViewCell".

The view does get centered, but the console says I shouldn't change this property.

How can I achieve this?

Before setting the property to false

After setting the property to false

Thank you very much.

Answer 1

UITableViewCell and UICollectionViewCell manages its contentView manually. In other words, UIKit relies on the cells' contentView having translatesAutoresizingMaskIntoConstraints being True so Changing the translatesAutoresizingMaskIntoConstraints property of the contentView of a UITableViewCell is not supported and will result in undefined behavior.

Don't do this:

cell.contentView.translatesAutoresizingMaskIntoConstraints = false

So, here is the full function for adding UIView in a UITableViewCell should be look like:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)

    //if already added the subview?
    if cell.contentView.subviews.count == 0 {

        let view = UIView() //your pinkView

        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor.purple

        cell.contentView.addSubview(view)

        view.centerXAnchor.constraint(equalTo: cell.contentView.centerXAnchor).isActive = true
        view.centerYAnchor.constraint(equalTo: cell.contentView.centerYAnchor).isActive = true
        view.widthAnchor.constraint(equalToConstant: 50.0).isActive = true
        view.heightAnchor.constraint(equalToConstant: 50.0).isActive = true
    }

    return cell
}