How to add UserDefaults into a task list - Swift - ios

Question

Iv been trying to add userDefaults to my code and trying to save for example a task so the next time i open the app i can still see the task .
didnt quit understood how userDefaults work.Maybe someone can help me?
taskList VC file:
#IBAction func doneButton_Tapped(_ sender: Any) {
var newTask = taskList()
newTask.name = taskNameField.text!
newTask.dueDate = dueDatePicker.date
newTask.dateCreated = Date()
taskArr.append(newTask)
didCreateTask = true
self.navigationController?.popViewController(animated: true)
}
mainVC file:
struct taskList {
var name: String!
var dateCreated: Date!
var dueDate:Date!
}
private let listIdentifier = "listIdentifier"
var taskArr: [taskList] = []
let defauls = UserDefaults.standard
class ViewController: UIViewController {
#IBOutlet var tableView:UITableView!
override func viewDidLoad() {
super.viewDidLoad()
self.title = "Tasks List"
tableView.delegate = self
tableView.dataSource = self
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
tableView.reloadData()
}
#IBAction func newTaskButton_Tapped(_ sender: Any){
self.performSegue(withIdentifier: "newTaskSague", sender: nil)
}
}
extension ViewController: UITableViewDelegate{
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
}
}
extension ViewController:UITableViewDataSource{
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {return taskArr.count}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: listIdentifier, for: indexPath) as! listCell
let row = indexPath.row
let formatter = DateFormatter()
cell.title?.text = taskArr[row].name
formatter.dateStyle = .medium
formatter.timeStyle = .short
cell.subTitle?.text = "Due: \(formatter.string(from: taskArr[row].dueDate))"
return cell
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete{
taskArr.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
}
}
}

Answer 1

With user defaults you can pretty much whatever you need but mind that is an internal database to small stuff as checking a boolean, an integer minimal data that you need as extra logic not as storage place, i you are planning to save a lot of entries of your Task model, you should consider to user CoreData.
What I suggest, is save an array of tasks in your UserDefaults (again if is not so much) and when you come from background, you need to check if your UserDefaults is empty, something like
override func viewDidLoad() {
super.viewDidLoad()
let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self, selector: #selector(appMovedToForeground), name: Notification.Name.UIApplicationWillEnterForeground, object: nil)
}
func appMovedToForeground() {
print("come from background")
}
For objects array you will need to use archiver, you will need to add to that method of appMoveToForeground something like:
guard let dataTasks = UserDefaults.standard.object(forKey: "task") as? Data else { return nil }
if let tasks = try NSKeyedUnarchiver.unarchivedObject(ofClasses: [Task.self], from: dataTasks){
if tasks.isNotEmpty() {
}
}
}

Answer 2

i still didnot get it how to implment this in my code .and im not trying to save big size of data just couple of them i dont need to use coreData