Error when trying to save with user defaults - ios

Question

Im having issues saving the table view data to user defaults, im getting the error " Cannot assign value of type '[String]' to type '[ViewController.ItemRow]' " in the load function. It gives the error at the line "items = loadedData". Does anyone know why its giving me this error!I dont know if im even doing it right.
import UIKit
import SafariServices
class ViewController: UIViewController, UIAdaptivePresentationControllerDelegate, UITextFieldDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var OrderNumberLabel: RoundedLabel2!
#IBOutlet weak var CostLabel: RoundedLabel2!
#IBOutlet weak var ProfitLabel: RoundedLabel2!
#IBOutlet weak var TotalLabel: RoundedLabel2!
#IBOutlet weak var itemTextField: UITextField!
#IBOutlet weak var priceTextField: UITextField!
#IBOutlet weak var saleTextField: UITextField!
var items: [ItemRow] = []
struct ItemRow
{
var first: String
var second: String
var third: String
}
override func viewDidLoad() {
super.viewDidLoad()
load()
// tableView.tableFooterView = UIView(frame: CGRect.zero)
}
func save(){
UserDefaults.standard.set(items, forKey: "saved")
}
func load(){
if let loadedData:[String] = UserDefaults.standard.value(forKey: "saved") as? [String]{
items = loadedData
tableView.reloadData()
}
}
#IBAction func addButtonTapped(_ sender: Any) {
insertNewItems()
save()
// profit()
//
}
// func profit(){
// let priceValue = Double(priceTextField.text!)
// let saleValue = Double(saleTextField.text!)
//
// if priceValue != nil && saleValue != nil {
//
// let outputValue = Double (priceValue! - saleValue!)
//
// ProfitLabel.text = "\(outputValue)"
// }
// }
func insertNewItems() {
let newVideoRow = ItemRow(first: itemTextField.text!, second: priceTextField.text!, third: saleTextField.text!)
items.append(newVideoRow)
let indexPath = IndexPath(row: items.count - 1, section: 0)
tableView.beginUpdates()
tableView.insertRows(at: [indexPath], with: .automatic)
tableView.endUpdates()
itemTextField.text = ""
priceTextField.text = ""
saleTextField.text = ""
view.endEditing(true)
}
}
extension ViewController: UITableViewDelegate{
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let ItemTitle = items[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "ItemCell") as! ItemCell
cell.itemLabel.text = ItemTitle.first
cell.priceLabel.text = ItemTitle.second
cell.saleLabel.text = ItemTitle.third
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
items.remove(at: indexPath.row)
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .automatic)
tableView.endUpdates()
save()
}
}
}

Answer 1

Make your struct conform to the Codable protocol. This is as simple as changing one line to:-
struct ItemRow : Codable
Your save function can be:-
if let data = try? PropertyListEncoder().encode(items) {
UserDefaults.standard.set(data, forKey: "SavedItems")
}
And load can be:
let defaults = UserDefaults.standard
if let data = defaults.data(forKey: "SavedItems") {
items = try! PropertyListDecoder().decode([ItemRow].self, from: data)
tableView.reloadData()
}
A quick look around SO the opinion seems to be that this shouldn't be used for large data sets. So this will get you started, but it may be worth considering a solution a bit more 'database-y' if you need larger amounts of data (e.g. CoreData or Realm).