SwiftUI: Array with UserDefault- items keep coming back after removal - swiftui

Question

I am trying to make a list where the user can remove items. But the items keep coming back after I close the app. I can sense that it is because the List/ForEach keeps reading the original value of array, not the saved array. But I don't know how to make it do so. All the tutorials I could find on UserDefault talks about encoding the item in JSON then save it. The ones that are actually about using UserDefault on an array are too simplistic.
Any help is much appriciated. Thank you
import Foundation
import SwiftUI
let userDefaults = UserDefaults.standard
struct ContentView: View {
#State private var array: [String] = ["one", "two", "three"]
var body: some View {
List{
ForEach(array, id: \.self) { item in
Text("\(item)")
}
.onDelete(perform: delete)
Text("abc")
}
}
func delete(offsets: IndexSet){
array.remove(atOffsets: offsets)
userDefaults.set(array, forKey: "List1")
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}

Answer 1

try something like this, if you really want to use UserDefaults directly. Otherwise use AppStorage, see: https://developer.apple.com/documentation/swiftui/appstorage
struct ContentView: View {
#State private var array: [String] = []
var body: some View {
List{
ForEach(array, id: \.self) { item in
Text(item)
}.onDelete(perform: delete)
Text("abc")
}
.onAppear {
if let results = UserDefaults.standard.object(forKey: "List1") as? [String] {
array = results
} else {
array = ["one", "two", "three"]
}
}
}
func delete(offsets: IndexSet){
array.remove(atOffsets: offsets)
UserDefaults.standard.set(array, forKey: "List1")
}
}

Answer 2

Data should be kept in the model, while the view presents the data and responds to the change of the data.
import SwiftUI
class ViewModel: ObservableObject {
#Published private(set) var array: [String] = []
private struct Constants {
static let defaultsKey = "List1"
}
init() {
let array = restore()
if let array = array, array.count > 0 {
self.array = array
} else {
self.array = ["one", "two", "three"]
}
}
func delete(offsets: IndexSet){
array.remove(atOffsets: offsets)
store()
}
private func store() {
UserDefaults.standard.set(array, forKey: Constants.defaultsKey)
}
private func restore() -> Array<String>? {
return UserDefaults.standard.object(forKey: Constants.defaultsKey) as? Array<String>
}
}
struct ContentView: View {
#ObservedObject var viewModel: ViewModel
init(viewModel: ViewModel) {
self.viewModel = viewModel
}
var body: some View {
List{
ForEach(viewModel.array, id: \.self) { item in
Text("\(item)")
}
.onDelete(perform: delete)
Text("abc")
}
}
func delete(offsets: IndexSet){
viewModel.delete(offsets: offsets)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView(viewModel: ViewModel())
}
}