Add and delete cell from table view in swift

Question

I have a table view in the cell i'm having two text fields in which user can enter the data. Initially i'm showing 5 cells. There is a button on which when user click it add one more cell in the table view. Now when i hit a button it add a cell when textfields are empty. But when i add data in all 5 cell textfields and than hit add button app crashes by showing this error, Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'attempt to insert row 10 into section 0, but there are only 6 rows in section 0 after the update'

The code is try for adding and deleting cell is this,

extension FlashCardViewController: UITableViewDelegate,UITableViewDataSource, UITextFieldDelegate{

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return numberOfCell
}

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = flashCardTableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! FlashCardTableViewCell

    //cell.termTxt.delegate = self
    //allCellsText[indexPath.row] = cell.termTxt.text!
   // cell.definitionTxt.delegate = self
    return cell
}


func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 115
}

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    return true
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

    if editingStyle == .delete{
        numberOfCell -= 1
        allCellsText.remove(at: indexPath.row)
        flashCardTableView.beginUpdates()
        flashCardTableView.deleteRows(at: [indexPath], with: .automatic)
        flashCardTableView.endUpdates()
    }
}

func textFieldDidEndEditing(_ textField: UITextField) {
    allCellsText.append(textField.text!)
    print(allCellsText)
}

}

The code for add button is this,

 @IBAction func addCardBtnTapped(_ sender: Any) {

    numberOfCell += 1
    let indexPath = IndexPath(row: allCellsText.count+1, section: 0)
    flashCardTableView.beginUpdates()
    flashCardTableView.insertRows(at: [indexPath], with: .automatic)
    flashCardTableView.endUpdates()
    view.endEditing(true)
}

When i delete any cell it gives me error of index out of range. How can i achieve this goal? The view controllers looks like this,

Answer 1

The problem is in the way you create an indexPath for inserting a new row, fix it according to this:

@IBAction func addCardBtnTapped(_ sender: Any) {

    numberOfCell += 1
    // create indexPath from numberOfCell, not from allCellsText.count
    let indexPath = IndexPath(row: numberOfCell - 1, section: 0)
    flashCardTableView.beginUpdates()
    flashCardTableView.insertRows(at: [indexPath], with: .automatic)
    flashCardTableView.endUpdates()
    view.endEditing(true)
}

The problem is in creating the IndexPath using IndexPath(row: allCellsText.count+1, section: 0). The insertions and deletions on tableView HAVE to be consistent with the dataSource - if you add a new row, the numberOfRowsInSection HAVE to increase by one, too. Now in your case you increment numberOfCell by one, as you are supposed to do, but then you try to add the new row at an indexPath determined by allCellsText.count+1. The problem is that the allCellsText.count is not consistent with numberOfCell variable (notice that you append a new string everytime textFieldDidEndEditing gets called).

EDIT

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return allCellsTermText.count
}

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = flashCardTableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! FlashCardTableViewCell
    // configure it with the backing data
    cell.termTxt.text = allCellsTermText[indexPath.row]
    cell.definitionTxt.text = allCellsDefinitionText[indexPath.row]

    // now instead of this you will have to find a way how you will be
    // able to determine the row which needs to be changed and change the model
    // cell.termTxt.delegate = self
    // cell.definitionTxt.delegate = self
    return cell
}


func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 115
}

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    return true
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

    if editingStyle == .delete {
        allCellsTermText.remove(at: indexPath.row)
        allCellsDefinitionText.remove(at: indexPath.row)
        flashCardTableView.deleteRows(at: [indexPath], with: .automatic)
    }
}

func textFieldDidEndEditing(_ textField: UITextField) {
    // you should not append here, this will add a new row, you have to UPDATE the proper text 
    // allCellsText.append(textField.text!)
}


@IBAction func addCardBtnTapped(_ sender: Any) {

    // create a new row by appending new empty strings
    allCellsTermText.append("")
    allCellsDefinitionText.append("")

    let indexPath = IndexPath(row: allCellsTermText.count - 1, section: 0)
    flashCardTableView.insertRows(at: [indexPath], with: .automatic)
    view.endEditing(true)
}

Answer 2

If you want to use button to delete tableviewCell, any table view that allows rows to be deleted

Image TableViewCell delete with button

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! ATableViewCell

        cell.deleteButton.addTarget(self, action: #selector(nHapusTap(_:)), for: .touchUpInside)            

        return cell
    }

  @objc func nHapusTap(_ sender: UIButton) {
        let hitPoint = sender.convert(CGPoint.zero, to: tableView)
        if let indexPath = tableView.indexPathForRow(at: hitPoint) {

            self.dataArray.remove(at: indexPath.row)
            tableView.beginUpdates()
            tableView.deleteRows(at: [indexPath], with: .automatic)
            tableView.endUpdates()

        }

    }

Answer 3

You're doing it incorrect. You've added self as delegate to the termtxt and definitiontxt here.

cell.termTxt.delegate = self
    cell.definitionTxt.delegate = self

As many times as you end editing in these inputboxes, your delegate method gonna get hit where you're just appending the text in a array.

func textFieldDidEndEditing(_ textField: UITextField) {
    allCellsText.append(textField.text!)
    print(allCellsText)
}

When you call the add row button, the allCellsText size is 10 because endEditing has been called from two types of inputboxes. (10 is incorrect, you can't add 10th row after 5th row).

let indexPath = IndexPath(row: allCellsText.count+1, section: 0)

Solution: Either add some checks in your delegate method before appending anything in allCellsText array OR update your logic in addCardBtnTapped function, remove the dependency from allCellsText arrow. use something like:

let indexPath = IndexPath(row: numberOfCell+1, section: 0)