UITableview reloadRows not working properly in Swift 3 - ios

Question

I have created a UITableView with multiple sections consisting two cells with dynamic cell height. Added a button on second cell. On click of the button increasing the second cell height by changing the constraint height. Action method connected to the button is :
func increaseHeightOnClickOfButton(sender: UIButton) {
let indexPath = IndexPath(item: 1, section: sender.tag)
let cell = myTableView.cellForRow(at: indexPath) as! customCell
cell.viewHeightConstraint.constant = 100
self.myTableView.reloadRows(at: [indexPath], with: .automatic)
}
Issue: On clicking the button, cell height of second section increases rather than the first one.
I have also tried giving fix value of section like this :
let indexPath = IndexPath(item: 1, section: 0)
but it's not working.
It works only when I try this code:
func increaseHeightOnClickOfButton(sender: UIButton) {
let indexPath = IndexPath(item: 1, section: sender.tag)
let cell = myTableView.cellForRow(at: indexPath) as! customCell
cell.viewHeightConstraint.constant = 100
self.myTableView.reloadData()
}
But I don't want to reload the whole table view. Can anyone help me what I am doing wrong or is there any other approach to achieve it ?
Edit :
I did one more change, I removed :
self.myTableView.reloadRows(at: [indexPath], with: .automatic)
After clicking the button when I start scrolling the tableview, coming back to the same cell increases it's height. So I guess there is some issue with reloadRows.

Answer 1

You can use the following code to reload cell's height without reloading the whole data:
tableView.beginUpdates()
tableView.endUpdates()

Answer 2

Edit:
Modified first post to include a DataSource to track each row's height constraint constant.
Assuming your cell looks something like this:
you have added a UIView to the cell (orange view in my example)
added a label and button to the UIView
set leading, trailing, top and bottom constraints for the view
added a Height constraint to the view
connected IBOutlets and an IBAction for the button tap inside the cell class
set your table class for UITableViewAutomaticDimension
Then this should be a working example. Each time you tap a button, the Height constraint in that cell will be increased by 20-pts. No need to call reload anything...
class TypicalCell: UITableViewCell {
#IBOutlet weak var theLabel: UILabel!
#IBOutlet weak var viewHeightConstraint: NSLayoutConstraint!
var btnAction: (() -> ())?
#IBAction func didTap(_ sender: Any) {
btnAction?()
}
}
class TypicalTableViewController: UITableViewController {
// 2-D array of Row Heights
// 4 sections, with 4, 2, 6 and 3 rows
// all initialized to 40.0
var rowHeights: [[CGFloat]] = [
[40.0, 40.0, 40.0, 40.0],
[40.0, 40.0],
[40.0, 40.0, 40.0, 40.0, 40.0, 40.0],
[40.0, 40.0, 40.0]
]
override func viewDidLoad() {
super.viewDidLoad()
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 40.0
}
override func numberOfSections(in tableView: UITableView) -> Int {
return rowHeights.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return rowHeights[section].count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Typical", for: indexPath) as! TypicalCell
// Configure the cell...
cell.theLabel.text = "\(indexPath)"
// cells are reused, so set the cell's Height constraint every time
cell.viewHeightConstraint.constant = rowHeights[indexPath.section][indexPath.row]
// "call back" closure
cell.btnAction = {
// increment the value in our DataSource
self.rowHeights[indexPath.section][indexPath.row] += 20
// tell tableView it's being updated
tableView.beginUpdates()
// set the cell's Height constraint to the incremented value
cell.viewHeightConstraint.constant = self.rowHeights[indexPath.section][indexPath.row]
// tell tableView we're done updating - this will trigger an auto-layout pass
tableView.endUpdates()
}
return cell
}
}

Answer 3

Try reloading the Section:
self.tableView.reloadSections(IndexSet(integer: sender.tag), with: .automatic)