Facing issue in selecting and deselecting tableview cell in swift

Question

I am showing pincodes in tableview, and when i select a cell then it should select and if i tap on the same cell again then it should deselect(while tapping cell should work like switch)

but with below code

issue 1: initially i am unable to select 1st row but after selecting any other row and then able to select 1st row.. why? where am i wrong?

issue 2: only one time i can select deselect the same row with two tapping if i tap 3rd time continuously then unable to select the same row, why?.. please guide

class PincodeModel{
var name: String?
var id: Int?
var isSelected: Bool

init(name: String?, id: Int?, isSelected: Bool) {
    self.name = name
    self.id = id
    self.isSelected = isSelected
}
}


class FilterViewController: UIViewController {

var pincodePreviousIndex: Int = -1
var pincodes = [PincodeModel]()

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    
    for pincode in pincodeList {
        self.pincodes.append(PincodeModel(name: pincode, id: 0, isSelected: false))
    }
}


func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "SubFilterTableViewCell", for: indexPath) as! SubFilterTableViewCell
        cell.title.text = self.pincodes[indexPath.row].name

        if !self.pincodes.isEmpty {
            if self.pincodes[indexPath.row].isSelected == true {
                cell.tickImageView.image =  #imageLiteral(resourceName: "iconTick")
            }else {
                cell.tickImageView.image = UIImage()
            }
        }
    return cell
}

 // EDITED Code according to below answer
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
   
    self.pincodes[indexPath.row].isSelected = !self.pincodes[indexPath.row].isSelected

if self.pincodes[indexPath.row].isSelected == true {
self.filterData.pincode = pincodes[indexPath.row].name ?? ""
}else {
self.filterData.pincode = ""
}
if pincodePreviousIndex > 0 && pincodePreviousIndex != indexPath.row {
pincodes[pincodePreviousIndex].isSelected = false
}
pincodePreviousIndex = indexPath.row

}

this is working as i want when i select from index = 1, but if i select first row(index = 0) then the right mark remains if i select another row, why?

o/p with edited code:

Answer 1

For issue 1 - By using this line of code:

var pincodePreviousIndex: Int = 0

You cannot click the first row until you click another since

pincodes[pincodePreviousIndex].isSelected = false

Since you're defaulting to 0 in the beginning, that correlates to the first row.

For issue 2 - if you select row 2 (selected) and then select it again to deselect it: pincodePreviousIndex will hold the value of that row and then deselect it again with

pincodes[pincodePreviousIndex].isSelected = false

So even though you're selecting it it will deselect it.

I would do this at the top: var pincodePreviousIndex: Int = -1

and at the bottom:

if pincodePreviousIndex > 0 && pincodePreviousIndex != indexPath.row {
    pincodes[pincodePreviousIndex].isSelected = false
}