UserDefaults in a UITableViewCell not saving (swift3) - ios

Question

My code right now just lists things you manually enter. However when the user switches view controllers the code disappears. I tried to use userdefualts to save my current code in the number of rows in selection function but it does not save the items in the tableview cells. I just want to save whatever is in the tableview cells.
import UIKit
class ViewController: UIViewController, UITableViewDataSource {
var items: [String] = [""]
#IBOutlet weak var listTableView: UITableView!
#IBAction func addItem(_ sender: AnyObject) {
alert()
}
#IBOutlet weak var webView: UIWebView!
override func viewDidLoad() {
super.viewDidLoad()
listTableView.dataSource = self
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "listitem") as! ItemTableViewCell
cell.itemLabel.text = items[indexPath.row]
cell.preservesSuperviewLayoutMargins = false
cell.separatorInset = UIEdgeInsets.zero
cell.layoutMargins = UIEdgeInsets.zero
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
let userDefaults = UserDefaults.standard
userDefaults.setValue(items, forKey: "items")
userDefaults.synchronize()
return items.count
}
func alert(){
let alert = UIAlertController(title: "", message: "", preferredStyle: .alert)
alert.addTextField{
(textfield) in
textfield.placeholder = " Enter "
}
let add = UIAlertAction(title: "Add", style: .default){
(action) in
let textfield = alert.textFields![0]
self.items.append(textfield.text!)
self.listTableView.reloadData()
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel) {
(alert) in
}
alert.addAction(add)
alert.addAction(cancel)
present(alert, animated: true, completion: nil)
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
items.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .automatic)
}}

Answer 1

You have a number of issues in your code:
You never load your data back from UserDefaults. - This is the big one
There is no need to call synchronise.
You should save your data when data is added/deleted, not in numberOfRowsInSection.
It will look nicer if you insert a new row rather than reloading the whole table
I would suggest something like:
import UIKit
class ViewController: UIViewController, UITableViewDataSource {
var items = [String]()
#IBOutlet weak var listTableView: UITableView!
#IBAction func addItem(_ sender: AnyObject) {
alert()
}
#IBOutlet weak var webView: UIWebView!
override func viewDidLoad() {
super.viewDidLoad()
listTableView.dataSource = self
self.items = UserDefaults.standard.stringArray(forKey:"items") ?? [String]()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "listitem") as! ItemTableViewCell
cell.itemLabel.text = items[indexPath.row]
cell.preservesSuperviewLayoutMargins = false
cell.separatorInset = UIEdgeInsets.zero
cell.layoutMargins = UIEdgeInsets.zero
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func saveData() {
userDefaults.standard.set(items, forKey: "items")
}
func alert(){
let alert = UIAlertController(title: "", message: "", preferredStyle: .alert)
alert.addTextField{
(textfield) in
textfield.placeholder = " Enter "
}
let add = UIAlertAction(title: "Add", style: .default){
(action) in
guard let textfield = alert.textFields?.first else {
return
}
if let newText= textfield.text {
self.items.append(newText)
saveData()
let indexPath = IndexPath(row: items.count - 1, section: 0)
self.listTableView.insertRows(at: [indexPath], with: .automatic)
}
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel) {
(alert) in
}
alert.addAction(add)
alert.addAction(cancel)
present(alert, animated: true, completion: nil)
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
items.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .automatic)
saveData()
}
}
Also, you shouldn't really use UserDefaults for data storage this way, but I presume this is just a simple learning exercise.