Swift - Multiple TableView checkmark - save and load choice - ios

Question

Im trying to save and load choice from TableView Multiple checkmarks.
I have a code ready, but I don't know how to save the selection. And how to load the selection at the opening of the list.
MY CODE:
var selectedCells = [IndexPath]()
var selectedAreas = [String]()
var Areas = [] //my text for the cells..
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return Areas.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")!
cell.textLabel?.text = Areas[indexPath.row]
cell.accessoryType = selectedCells.contains(indexPath) ? .checkmark : .none
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let selectedCell = tableView.cellForRow(at: indexPath)
selectedCells.append(indexPath)
if selectedCell?.accessoryType == .checkmark {
if let indexremove = selectedAreas.firstIndex(of: (Areas[indexPath.row])) {
selectedAreas.remove(at: indexremove)
}
selectedCell?.accessoryType = .none
print(selectedCells)
print(selectedAreas)
print("remove ")
selectedCells = selectedCells.filter {$0 != indexPath}
} else {
print(selectedCells)
print(selectedAreas)
print("add")
selectedAreas.append(Areas[indexPath.row])
selectedCell?.accessoryType = .checkmark
}
}

Answer 1

Don't use multiple arrays as data source. That's pretty bad practice and inefficient.
Delete them
var selectedCells = [IndexPath]()
var selectedAreas = [String]()
Declare Area as struct and add an isSelected member
struct Area {
let name : String
var isSelected : Bool
init(name : String, isSelected : Bool = false) {
self.name = name
self.isSelected = isSelected
}
}
var areas = [Area(name: "Foo"), Area(name: "Bar")]
In cellForRowAt assign the checkmark depending on isSelected
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
let area = areas[indexPath.row]
cell.textLabel?.text = area.name
cell.accessoryType = area.isSelected ? .checkmark : .none
return cell
}
In didSelectRow toggle isSelected and reload the row (yes, only two lines of code)
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
areas[indexPath.row].isSelected.toggle()
tableView.reloadRows(at: [indexPath], with: .none)
}
You get the selected areas with
let selectedAreas = areas.filter{$0.isSelected}
and an array of the names
let selectedAreaNames = areas.filter{$0.isSelected}.map{$0.name}
To load and save the names to UserDefaults add these two methods
func saveSelection()
{
let selectedAreaNames = areas.filter{$0.isSelected}.map{$0.name}
UserDefaults.standard.set(selectedAreaNames, forKey: "selectedNames")
}
func loadSelection()
{
guard let selectedAreaNames = UserDefaults.standard.array(forKey: "selectedNames") as? [String] else { return }
for (index, area) in areas.enumerated() {
areas[index].isSelected = selectedAreaNames.contains(area.name)
}
tableView.reloadData()
}