Failure while attempt to find specific cell in table view swift - swift

Question

I want to find specific cell class in my table view. I use following code:
func setConfirmEnabledIfNeed(){
let ip = IndexPath(row: 8, section: 0)
if let cell = tableView.cellForRow(at: ip) as? ConfirmBtnCell {
print("find confirm cell")
}
let c = tableView.cellForRow(at: ip) as? ConfirmBtnCell
print("type of cell \(type(of: c))")
}
print("find confirm cell") is never called, however, second print output: type of cell Optional<ConfirmBtnCell>, what is obviously what i need. But why first print not called?
My cell for row look like this:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let item = viewModel.items[indexPath.row]
switch item {
case .selectable(let value, let placeholder, let type):
let selectionCell = tableView.dequeueReusableCell(withIdentifier: "SelectionCell") as! SelectionCell
if let placeholder = placeholder { selectionCell.setPlaceholder(placeholder) }
if let text = value as? String, !text.isEmpty { selectionCell.hidePlaceholder();
selectionCell.textLbl.text = text }
if let date = value as? Date { selectionCell.hidePlaceholder();
selectionCell.textLbl.text = DateFormatterUtil.getReadableStringFromDate(date) }
return selectionCell
case .back:
return tableView.dequeueReusableCell(withIdentifier: "BackBtnCell") as! BackBtnCell
case .confirm:
return tableView.dequeueReusableCell(withIdentifier: "ConfirmBtnCell") as! ConfirmBtnCell
case .editableNumbers(let text, let placeholder, let type):
let editableCell = tableView.dequeueReusableCell(withIdentifier: "TextEditCell") as! TextEditCell
editableCell.setup(isNumerical: true)
if let placeholder = placeholder { editableCell.setPlaceholder(placeholder) }
if let text = text {editableCell.hidePlaceholder(); editableCell.txtf.text = text }
editableCell.textChanged = {[weak self] text in
guard let text = text else { return }
if type == .sumCash {
self?.viewModel.collectedInfo[CorrectionChequeViewModel.infoKeys.sumCash.rawValue] = text
self?.setConfirmEnabledIfNeed()
}
if type == .sumElectronic {
self?.viewModel.collectedInfo[CorrectionChequeViewModel.infoKeys.sumElectronic.rawValue] = text
}
}
return editableCell
case .editableText(let text, let placeholder, let type):
let editableCell = tableView.dequeueReusableCell(withIdentifier: "TextEditCell") as! TextEditCell
editableCell.setup(isNumerical: false)
if let placeholder = placeholder { editableCell.setPlaceholder(placeholder) }
if let text = text {editableCell.hidePlaceholder(); editableCell.txtf.text = text }
editableCell.textChanged = {[weak self] text in
guard let text = text else { return }
if type == .sumCash {
self?.viewModel.collectedInfo[CorrectionChequeViewModel.infoKeys.description.rawValue] = text
}
if type == .sumElectronic {
self?.viewModel.collectedInfo[CorrectionChequeViewModel.infoKeys.number.rawValue] = text
}
}
return editableCell
default:
return UITableViewCell()
}
}
UPDATE:
I find that code work if it's not called from table view cellForRow method. I tried to launch that block of code with dispatch_after, and it works.

Answer 1

In your if statement, the value for tableView.cellForRow(at: ip) as? ConfirmBtnCell is nil, so you never enter the block.
In the second statement (let c = tableView.cellForRow(at: ip) as? ConfirmBtnCell), the value of c is an Optional<ConfirmBtnCell>. If you unwrap the optional, you will see that its unwrapped value is also a nil.
If your row is not visible, tableView.cellForRow will return a nil even when the cell is set. See the Apple Documentation.