Swift expandable table view header for sections problem

Question

I have question about expandable table view by header. I made it for section zero and its working correctly but when I try to make it same thing for section one too it gives error which is

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (0) must be equal to the number of rows contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

If I didn't trigger second header function, first one still working. When I clicked second header ( which is section one) it gives that error.

Here my header view code:

    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    if section == 0 {
        let button = UIButton(type: .system)
        button.setTitle("Kapat", for: .normal)
        button.setTitleColor(.black, for: .normal)
        button.backgroundColor = .lightGray
        button.titleLabel!.font = UIFont.boldSystemFont(ofSize: 14)
        button.addTarget(self, action: #selector(handleExpandCloseForAlim(sender:)), for: .touchUpInside)
        return button
    }
    if section == 1 {
        let button2 = UIButton(type: .system)
        button2.setTitle("Kapat", for: .normal)
        button2.setTitleColor(.black, for: .normal)
        button2.backgroundColor = .lightGray
        button2.titleLabel!.font = UIFont.boldSystemFont(ofSize: 14)
        button2.addTarget(self, action: #selector(handleExpandCloseForTeslim(sender:)), for: .touchUpInside)
        return button2
    }
    else{
        return nil
    }
}

Here my action functions:

    @objc func handleExpandCloseForAlim(sender: UIButton) {

        var indexPaths = [IndexPath]()
        for row in self.userAdressDict.indices{

            let indexPath = IndexPath(row: row, section: 0)
            indexPaths.append(indexPath)
        }
        let indexPath = IndexPath(row: (sender.tag), section: 0)
        let adresso = self.userAdressDict[indexPath.row]
        let isExp = adresso.isExpanded
        adresso.isExpanded = !isExp!
        if isExp! {
            tableView.deleteRows(at: indexPaths, with: .fade)
        }else {
            tableView.insertRows(at: indexPaths, with: .fade)
        }
        print(adresso.isExpanded!, adresso.userMahalle!)

}
@objc func handleExpandCloseForTeslim(sender: UIButton) {
    var indexPathsForTeslim = [IndexPath]()
    for row in self.userAdressDictForTeslim.indices{

        let indexPath = IndexPath(row: row, section: 1)
        indexPathsForTeslim.append(indexPath)
    }
    let indexPath = IndexPath(row: (sender.tag), section: 1)
    let adresso = self.userAdressDictForTeslim[indexPath.row]
    let isExp = adresso.isExpanded
    adresso.isExpanded = !isExp!
    if isExp! {
        tableView.deleteRows(at: indexPathsForTeslim, with: .fade)
    }else {
        tableView.insertRows(at: indexPathsForTeslim, with: .fade)
    }
    print(adresso.isExpanded!, adresso.userMahalle!)
}

And here my numberOfRowsInSection part:

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if section == 0 {
        guard let element = self.userAdressDict.first as? adresStruct else { return 0 }

            if element.isExpanded {
                return self.userAdressDict.count
            }
            else {
               return 0
            }
        }
        if section == 1 {
              guard let teslim = self.userAdressDictForTeslim.last as? adresStruct else { return 0 }

              if teslim.isExpanded {
                  return self.userAdressDictForTeslim.count
              }
              else {
                 return 0
              }
        }

        return 1
}

I can't find any solution. I assume sender thing working wrongly but it may be another problem. I hope I asked clearly.Please help me.

Answer 1

I am not deep dive in your code but I copy-paste into an Xcode project to look into. So there is basic way to solve your problem, I hope it helps to you.

I assume your class is like that.

class Adres{
        var title: String = ""
        var isExpanded: Bool = true

        init(title: String, isExpanded: Bool){
            self.title = title
            self.isExpanded = isExpanded
        }
    }

And in there mainly 2 different variable for adresDict & adresDictForTeslim.

So I keep an lock array to doing logic stuff of expandable.

var keys: [Int] = [1,1]

<1> Show
<0> Hide

Now, the arrays elements are showing into UITableView, because its expanded.

There's mock data.

var userAdressDict = [Adres(title: "First Adres", isExpanded: true) ,Adres(title: "Second Adres", isExpanded: true)]
    var userAdressDictForTeslim = [Adres(title: "First Teslim", isExpanded: true),Adres(title: "Second Teslim", isExpanded: true)]

viewForHeaderInSection is same as well.

And for numberOfRowsInSection check array for key that if its expanded or not.

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if section == 0 {
            if self.keys[0] == 1 {
                return userAdressDict.count
            }else{
                return 0
            }
        }else{
            if self.keys[1] == 1 {
                return userAdressDictForTeslim.count
            }else{
                return 0
            }
        }
    }

Then check these keys in handler functions.

 @objc func handleExpandCloseForAlim(sender: UIButton) {

    if keys[0] == 0 {
        keys[0] = 1
    }else{
        keys[0] = 0
    }

    DispatchQueue.main.async {
        self.tableView.reloadData()
    }
}

If first array elements in table view is expanded close it, or not expand it.

Then in another function.

@objc func handleExpandCloseForTeslim(sender: UIButton) {

        if keys[1] == 0 {
            keys[1] = 1
        }else{
            keys[1] = 0
        }
        DispatchQueue.main.async {
            self.tableView.reloadData()
        }
    }

So far so good. It's working on my simulator.

Then there's more efficient way to handle keys of expanded.

Make your UIButton's of the sectionHeader as public variable in your ViewController and control it if it's title is "Kapat" and clicked then it must be "Aç" or if its "Aç" and touched it must be "Kapat".