Changing a boolean in a variable from Identifiable struct - ios

Question

import Foundation
import SwiftUI
struct Item: Identifiable, Codable{
var id = UUID()
var image: String
var name: String
var price: Int
var isFavorite: Bool
}
class Model: ObservableObject{
#Published var group = [Item]() {
didSet {
if let encoded = try? JSONEncoder().encode(group){
UserDefaults.standard.set(encoded, forKey: "peopleKey")
}
}
}
init(){
if let savedItems = UserDefaults.standard.data(forKey: "peopleKey"),
let decodedItems = try? JSONDecoder().decode([Item].self, from: savedItems) {
group = decodedItems
} else {
group = itemData
}
}
var itemData: [Item] = [
Item(image: "imageGIFT", name: "Flower",price: 5 , isFavorite: false),
Item(image: "imageGIFT", name: "Coffe Cup",price: 9 , isFavorite: false),
Item(image: "imageGIFT", name: "Teddy Bear",price: 2 , isFavorite: false),
Item(image: "imageGIFT", name: "Parfume",price: 8 , isFavorite: false)
]
}
I am trying to change variables on this struct and I define as var but after encode and decode they has been let. I changed let part to var then Xcode gived an error.

Answer 1

here is my test code that shows doing model.people[0].myPerson.toggle() in the Button
does work. I have made some minor mods and added some comments to the code.
I suggest again, read the very basics of Swift,
in particular the array section at: https://docs.swift.org/swift-book/LanguageGuide/CollectionTypes.html.
Without understanding these very basic concepts you will keep struggling to code your App.
Note, there is probably no need for the myPeople array in your Model, but if that's what you want to have.
struct Person: Identifiable{
let id = UUID()
var name: String
var age: Int
var job: String
var myPerson: Bool
}
class Model: ObservableObject {
#Published var people: [Person] = []
#Published var myPeople: [Person] = []
init(){
addPeople()
}
// completely useless
func addPeople(){
people = peopleData
myPeople = peopleData.filter { $0.myPerson }
}
// here inside the class and using `Person` not `person`
var peopleData = [
Person(name: "Bob", age: 22, job: "Student", myPerson: false),
Person(name: "John", age: 26, job: "Chef", myPerson: false)
]
}
struct ContentView: View {
#StateObject var model = Model()
var body: some View {
VStack {
VStack {
// this `myPeople` array is empty at first, nothing is displayed
ForEach(model.myPeople) { person in
VStack(alignment: .leading){
Text("Name: \(person.name)").foregroundColor(.blue)
Text("Age: \(person.age)").foregroundColor(.blue)
Text("Job: \(person.job)").foregroundColor(.blue)
Text("myPerson: " + String(person.myPerson)).foregroundColor(.blue)
}.padding()
}
}
VStack {
// this `people` array has two items in it
ForEach(model.people) { person in
VStack(alignment: .leading){
Text("Name: \(person.name)").foregroundColor(.red)
Text("Age: \(person.age)").foregroundColor(.red)
Text("Job: \(person.job)").foregroundColor(.red)
Text("myPerson: " + String(person.myPerson)).foregroundColor(.red)
}.padding()
}
}
Button("Click") {
print("\n--> before name: \(model.people[0].name) ")
print("--> before myPerson: \(model.people[0].myPerson) ")
model.people[0].name = "Franz"
model.people[0].myPerson.toggle()
print("\n--> after name: \(model.people[0].name) ")
print("--> after myPerson: \(model.people[0].myPerson) ")
// update the myPeople array (the blue items)
model.myPeople = model.people.filter { $0.myPerson }
}
}
}
}
Alternatively, you could use this code using only one array of people: [Person]:
class Model: ObservableObject {
#Published var people: [Person] = []
init(){
addPeople()
}
func addPeople() {
people = peopleData
}
// here inside the class and using `Person` not `person`
var peopleData = [
Person(name: "Bob", age: 22, job: "Student", myPerson: false),
Person(name: "John", age: 26, job: "Chef", myPerson: false)
]
}
struct ContentView: View {
#StateObject var model = Model()
var body: some View {
VStack {
VStack {
// here filter on myPerson=true
ForEach(model.people.filter { $0.myPerson }) { person in
VStack(alignment: .leading){
Text("Name: \(person.name)").foregroundColor(.blue)
Text("Age: \(person.age)").foregroundColor(.blue)
Text("Job: \(person.job)").foregroundColor(.blue)
Text("myPerson: " + String(person.myPerson)).foregroundColor(.blue)
}.padding()
}
}
VStack {
// here filter on myPerson=false
ForEach(model.people.filter { !$0.myPerson }) { person in
VStack(alignment: .leading){
Text("Name: \(person.name)").foregroundColor(.red)
Text("Age: \(person.age)").foregroundColor(.red)
Text("Job: \(person.job)").foregroundColor(.red)
Text("myPerson: " + String(person.myPerson)).foregroundColor(.red)
}.padding()
}
}
Button("Click") {
model.people[0].name = "Franz"
model.people[0].myPerson.toggle()
}
}
}
}