Why does the TextField in the List stop updating? - swiftui

Question

I started studying SwiftUI and wanted to make a prototype of standard reminders, like in an iPhone. It seems nothing complicated, there is a List, in each cell a TextField.
But I ran into a problem: when we change the text in the TextField using onChange, then we accordingly tell the view model to update our objects.
And when the objects are updated, the entire List is redrawn and the editing of the current TextField is reset (you can neither remove more than one character, nor add). You have to click on the text again to continue editing.
Does anyone know how to treat this?
This is my code:
import SwiftUI
struct Fruit: Identifiable {
let id = UUID()
let name: String
func updateName(newName: String) -> Fruit {
return Fruit(name: newName)
}
}
class ViewModel: ObservableObject {
#Published var fruits: [Fruit] = [Fruit(name: "apple"), Fruit(name: "banana"), Fruit(name: "orange")]
func updateName(newName: String, fruit: Fruit) {
if let index = fruits.firstIndex(where: { $0.id == fruit.id }) {
fruits[index] = fruit.updateName(newName: newName)
}
}
}
struct ListView: View {
#StateObject var viewModel = ViewModel()
var body: some View {
List {
ForEach(viewModel.fruits) { fruit in
ListViewRow(fruit: fruit)
}
}
.environmentObject(viewModel)
}
}
struct ListViewRow: View {
#EnvironmentObject var viewModel: ViewModel
#State var fruitTextField: String
let fruit: Fruit
init(fruit: Fruit) {
self.fruit = fruit
_fruitTextField = State(initialValue: fruit.name)
}
var body: some View {
TextField("", text: $fruitTextField)
.onChange(of: fruitTextField) { newValue in
viewModel.updateName(newName: newValue, fruit: fruit)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ListView()
}
}

Answer 1

You can simplify it even more with:
struct Fruit: Identifiable {
let id = UUID()
var name: String
}
class ViewModel: ObservableObject {
#Published var fruits: [Fruit] = [Fruit(name: "apple"), Fruit(name: "banana"), Fruit(name: "orange")]
}
struct ListView: View {
#StateObject var viewModel = ViewModel()
var body: some View {
List {
ForEach($viewModel.fruits) { $fruit in
ListViewRow(fruit: $fruit)
}
}
}
}
struct ListViewRow: View {
#Binding var fruit: Fruit
var body: some View {
TextField("", text: $fruit.name)
}
}
That being said, you really need to view the Apple Swift Tutorials that were linked in the comments.
Edit: Full Project Code for Lorem Ipsum:
//
// ContentView.swift
// FruitApp
//
// Created by Developer on 11/27/21.
//
import SwiftUI
struct Fruit: Identifiable {
let id = UUID()
var name: String
}
class ViewModel: ObservableObject {
#Published var fruits: [Fruit] = [Fruit(name: "apple"), Fruit(name: "banana"), Fruit(name: "orange")]
}
struct ListView: View {
#StateObject var viewModel = ViewModel()
var body: some View {
List {
ForEach($viewModel.fruits) { $fruit in
ListViewRow(fruit: $fruit)
}
}
}
}
struct ListViewRow: View {
#Binding var fruit: Fruit
var body: some View {
TextField("", text: $fruit.name)
}
}
struct ContentView: View {
var body: some View {
ListView()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}