Set UITableView's superview height accordingly to the number of table view cells

Question

My UITableView is embedded within a UIView, I would like that this superview's height change according to the number of UITableViewCells the table view has.

That mean, if the tableView has 1 cell, UIView will be the size of this cell, if there are 2 cells, the UIView will grow to the size of 2 cells.

Answer 1

If you are using Autolayout constraints, you can just update UITableView's height constraint itself and that should do the job.

Here are the basic steps:

1. Subclass UITableView:

   class CustomTableView: UITableView {
   
       var maximumTableViewHeight: CGFloat = UIScreen.main.bounds.size.height
   
       private var heightConstraint: NSLayoutConstraint!
   
       override func reloadData() {
          super.reloadData()
           self.heightConstraint.constant = min(self.contentSize.height, maximumTableViewHeight)
       }
   
       override func awakeFromNib() {
           super.awakeFromNib()
   
           self.heightConstraint = NSLayoutConstraint(item: self, attribute: .height, relatedBy: .equal, toItem: nil,
                                                      attribute: .notAnAttribute, multiplier: 1, constant: 0)
           self.addConstraint(heightConstraint)
       }
   
   }
   

2. Storyboard that has our subclassed CustomTableView

3. Then your view controller:

   class ViewController: UIViewController, UITableViewDataSource {
   
       @IBOutlet var tableView: CustomTableView!
       private let cellIdentifier = "Cell"
   
       var dataSource: [Int] = [1, 2, 3] {
           didSet {
               self.tableView.reloadData()
           }
       }
   
       override func viewDidLoad() {
           super.viewDidLoad()
   
           self.tableView.dataSource = self
           self.tableView.maximumTableViewHeight = 400 // Adjust as per your max height
       }
   
       @IBAction func addCell(_ sender: Any) {
           let count = self.dataSource.count + 1
           self.dataSource.append(count)
   
           let scrollToIndexPath = IndexPath(row: count - 1, section: 0)
           DispatchQueue.main.async {
               self.tableView.scrollToRow(at: scrollToIndexPath, at: .bottom, animated: false)
           }
       }
   
       func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
           return self.dataSource.count
       }
   
       func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
           var cell: UITableViewCell! = tableView.dequeueReusableCell(withIdentifier: cellIdentifier)
           if cell == nil {
               cell = UITableViewCell(style: .default, reuseIdentifier: cellIdentifier)
           }
   
           cell.textLabel?.text = "Value: " + String(dataSource[indexPath.row])
           return cell
       }
   
   }
   

That yields:

Notice the red area, thats the parent UIView of UITableView

Answer 2

I would add one more UIView to UITableViewCell's contentView which I would use as content view. Then I would set backgroundColor of real contentView