Assign an upper bound for the height of a tableview? - ios

Question

I have a tableview whose height is dynamically adjusted. The height is adjusted so that the tableview only includes a certain number of rows, and no empty rows. So, if there are only 2 rows then the height is smaller, and if there are 4 rows then the height is bigger. However, I do not want its height to go past a certain point. How can I allow the height to be dynamically adjusted, while not letting the height ever reach past a certain point?
This is my code:
#IBOutlet var tableView: UITableView!
#IBOutlet var tableViewHeightConstraint: NSLayoutConstraint!
var items: [String] = ["Swift", "Is", "So", "Amazing"]
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.items.count;
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier: "Cell") as! UITableViewCell
// Make sure the table view cell separator spans the whole width
cell.preservesSuperviewLayoutMargins = false
cell.separatorInset = UIEdgeInsets.zero
cell.layoutMargins = UIEdgeInsets.zero
cell.textLabel?.text = self.items[indexPath.row]
return cell
}
override func viewWillAppear(_ animated: Bool) {
// Adjust the height of the tableview
tableView.frame = CGRect(x: tableView.frame.origin.x, y: tableView.frame.origin.y, width: tableView.frame.size.width, height: tableView.contentSize.height)
// Add a border to the tableView
tableView.layer.borderWidth = 1
tableView.layer.borderColor = UIColor.black.cgColor
print("We ran ViewWillAppear")
}
// This function is used for adjusting the height of the tableview
override func viewDidLayoutSubviews(){
tableView.frame = CGRect(x: tableView.frame.origin.x, y: tableView.frame.origin.y, width: tableView.frame.size.width, height: tableView.contentSize.height)
tableView.reloadData()
}
// Allow cell deletion in tableview
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let delete = UITableViewRowAction(style: .destructive, title: "Delete") { (action, indexPath) in
// delete item at indexPath
self.items.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
self.tableViewHeightConstraint.constant = self.tableView.contentSize.height - 44
print(self.items)
print("Number of rows: \(tableView.numberOfRows(inSection: 0))")
}
delete.backgroundColor = UIColor.blue
return [delete]
}

Answer 1

In viewWillAppear , you can try
let limit:CGFloat = 900.0
if tableView.contentSize.height < limit {
tableView.frame = CGRect(x: tableView.frame.origin.x, y: tableView.frame.origin.y, width: tableView.frame.size.width, height: tableView.contentSize.height)
}
else {
tableView.frame = CGRect(x: tableView.frame.origin.x, y: tableView.frame.origin.y, width: tableView.frame.size.width, height: limit )
}
Or set value to
tableViewHeightConstraint.constant = ( tableView.contentSize.height < limit ) ? tableView.contentSize.height : limit
self.view.layoutIfNeeded()