List row reset value - swiftui

I have a List, with custom Stepper inside each row. Therefore, when I scroll my stepper is reset. (The increment and decrement works when is visible. When it disappear, it's reset. Don't keep the state. It's alway's reset).
Xcode: v14.2 / Simulator iOS: 16.2
struct Product: Codable, Hashable, Identifiable {
let id: String
let name: String
let step: Int
let quantity: Int
let priceHT: Double
}
class ProductViewModel: ObservableObject {
#Published var products = [Product]()
...
}
struct ProductListView: View {
#EnvironmentObject var productViewModel: ProductViewModel
var body: some View {
List(productViewModel.products) { product in
ProductRowView(product: product)
  }
}
}
My List row:
I tried to modify #State with #binding, but without success.
struct ProductRowView: View {
#State var product: Product
var body: some View {
HStack {
VStack {
Text(product.name)
Text(String(format: "%.2f", product.priceHT) + "€ HT")
}
Spacer()
MyStepper(product: $product, value: product.quantity)
.font(.title)
}
}
}
My Custom stepper:
struct MyStepper: View {
#Binding var product: Product
#State var value: Int = 0
var body: some View {
HStack {
VStack() {
HStack {
Button(action: {
value -= product.step
if let row = orderViewModel.productsOrder.firstIndex(where: { $0.name == product.name }) {
let order = Product(id: product.id, name: product.name, step: product.step, quantity: value, priceHT: product.priceHT)
if (value == 0) {
orderViewModel.productsOrder.remove(at: row)
} else {
orderViewModel.productsOrder[row] = order
}
}
}, label: {
Image(systemName: "minus.square.fill")
})
Text(value.formatted())
Button(action: {
value += product.step
let order = Product(id: product.id, name: product.name, step: product.step, quantity: value, priceHT: product.priceHT)
if let row = orderViewModel.productsOrder.firstIndex(where: { $0.name == product.name }) {
orderViewModel.productsOrder[row] = order
} else {
orderViewModel.productsOrder.append(order)
}
}, label: {
Image(systemName: "plus.app.fill")
})
}
Text(product.unit)
}
}
}
}
Thks
EDIT / RESOLVED
Here is the solution for my case :
Change type of quantity. let to var
struct Product: Codable, Hashable, Identifiable {
...
var quantity: Int
...
}
Delete #State in MyStepper and replace value by product.quantity

Use bindings for that, e.g.
struct ProductListView: View {
#EnvironmentObject var model: Model
var body: some View {
List($model.products) { $product in
ProductRowView(product: $product)
}
}
}
struct ProductRowView: View {
#Binding var product: Product // now you have write access to the Product struct
...
However, to make the View reusable and to help with previewing, it's best to pass in only the simple types the View needs, e.g.
struct TitlePriceView: View {
let title: String
#Binding var price: Double
// etc.
TitlePriceView(title: product.title, price: $product.price)

Related

SwiftUI - Subtotal TextField entries across multiple views

I have multiple views created by a ForEACH. Each View has a textfield where a user can enter a number. I would like to subtotal each entry in each view. In other words subtotal the binding in each view.
Is my approach wrong?
ForEach(someArray.allCases, id: \.id) { item in
CustomeRowView(name: item.rawValue)
}
struct CustomeRowView: View {
var name: String
#State private var amount: String = ""
var body: some View {
VStack {
HStack {
Label(name, systemImage: image)
VStack {
TextField("Amount", text: $amount)
.frame(width: UIScreen.main.bounds.width / 7)
}
}
}
}
}
Any help would be greatly appreciated.
there are many ways to achieve what you ask. I present here a very
simple approach, using an ObservableObject to keep the info in one place.
It has a function to add to the info dictionary fruits.
A #StateObject is created in ContentView to keep one single source of truth.
It is passed to the CustomeRowView view using #ObservedObject, and used to tally
the input of the TextField when the return key is pressed (.onSubmit).
import SwiftUI
#main
struct TestApp: App {
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
class FruitCake: ObservableObject {
#Published var fruits: [String : Int] = ["apples":0,"oranges":0,"bananas":0]
// adjust for you purpose
func add(to name: String, amount: Int) {
if let k = fruits.keys.first(where: {$0 == name}),
let sum = fruits[k] {
fruits[k] = sum + amount
}
}
}
struct ContentView: View {
#StateObject var fruitCake = FruitCake()
var body: some View {
VStack {
ForEach(Array(fruitCake.fruits.keys), id: \.self) { item in
CustomeRowView(name: item, fruitCake: fruitCake)
}
}
}
}
struct CustomeRowView: View {
let name: String
#ObservedObject var fruitCake: FruitCake
#State private var amount = 0
var body: some View {
HStack {
Label(name, systemImage: "info")
TextField("Amount", value: $amount, format: .number)
.frame(width: UIScreen.main.bounds.width / 7)
.border(.red)
.onSubmit {
fruitCake.add(to: name, amount: amount)
}
// subtotal
Text("\(fruitCake.fruits[name] ?? 0)")
}
}
}

iOS 15: Navigation link popping out, again

In the last few months, many developers have reported NavigationLinks to unexpectedly pop out and some workarounds have been published, including adding another empty link and adding .navigationViewStyle(StackNavigationViewStyle()) to the navigation view.
Here, I would like to demonstrate another situation under which a NavigationLink unexpectedly pops out:
When there are two levels of child views, i.e. parentView > childLevel1 > childLevel2, and childLevel2 modifies childLevel1, then, after going back from level 2 to level 1, level 1 pops out and parentView is shown.
I have filed a bug report but not heard from apple since. None of the known workarounds seem to work. Does someone have an idea what to make of this? Just wait for iOS 15.1?
Below is my code (iPhone app). In the parent view, there is a list of persons from which orders are taken. In childLevel1, all orders from a particular person are shown. Each order can be modified by clicking on it, which leads to childLevel2. In childLevel2, several options are available (here only one is shown for the sake of brevity), which is the reason why the user is supposed to leave childLevel2 via "< Back".
import SwiftUI
struct Person: Identifiable, Hashable {
let id: Int
let name: String
var orders: [Order]
}
struct Pastry: Identifiable, Hashable {
let id: Int
let name: String
}
struct Order: Hashable {
var paId: Int
var n: Int // used only in the real code
}
class Data : ObservableObject {
init() {
pastries = [
Pastry(id: 0, name: "Prezel"),
Pastry(id: 1, name: "Donut"),
Pastry(id: 2, name: "bagel"),
Pastry(id: 3, name: "cheese cake"),
]
persons = [
Person(id: 0, name: "Alice", orders: [Order(paId: 1, n: 1)]),
Person(id: 1, name: "Bob", orders: [Order(paId: 2, n: 1), Order(paId: 3, n: 1)])
]
activePersonsIds = [0, 1]
}
#Published var activePersonsIds: [Int] = []
#Published var persons: [Person] = []
#Published var pastries: [Pastry]
#Published var latestOrder = Order(paId: 0, n: 1)
lazy var pastryName: (Int) -> String = { (paId: Int) -> String in
if self.pastries.first(where: { $0.id == paId }) == nil {
return "undefined pastryId " + String(paId)
}
return self.pastries.first(where: { $0.id == paId })!.name
}
var activePersons : [Person] {
return activePersonsIds.compactMap {id in persons.first(where: {$0.id == id})}
}
}
#main
struct Bretzel_ProApp: App {
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
struct ContentView: View {
#Environment(\.colorScheme) var colorScheme
#StateObject var data = Data()
var body: some View {
TabView1(data: data)
// in the real code, there are more tabs
}
}
struct TabView1: View {
#StateObject var data: Data
var body: some View {
NavigationView {
List {
ForEach(data.activePersons, id: \.self) { person in
NavigationLink(
destination: EditPerson(data: data, psId: person.id),
label: {
VStack (alignment: .leading) {
Text(person.name)
}
}
)
}
}
.listStyle(PlainListStyle())
.navigationTitle("Orders")
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
struct EditPerson: View {
#ObservedObject var data: Data
var psId: Int
var body: some View {
let pindex: Int = data.persons.firstIndex(where: { $0.id == psId })!
let p: Person = data.persons[pindex]
List() {
ForEach (0...p.orders.count-1, id: \.self) { loop in
Section(header:
HStack() {
Text("BESTELLUNG " + String(loop+1))
}
) {
EPSubview1(data: data, psId: psId, loop: loop)
}
}
}.navigationTitle(p.name)
.listStyle(InsetGroupedListStyle())
}
}
struct EPSubview1: View {
#ObservedObject var data: Data
var psId: Int
var loop: Int
var body: some View {
let pindex: Int = data.persons.firstIndex(where: { $0.id == psId })!
let p: Person = data.persons[pindex]
let o1: Order = p.orders[loop]
NavigationLink(
destination: SelectPastry(data: data)
.onAppear() {
data.latestOrder.paId = o1.paId
}
.onDisappear() {
data.persons[pindex].orders[loop].paId = data.latestOrder.paId
},
label: {
VStack(alignment: .leading) {
Text(String(o1.n) + " x " + data.pastryName(o1.paId))
}
}
)
}
}
struct SelectPastry: View {
#ObservedObject var data : Data
var body: some View {
VStack {
List {
ForEach(data.pastries, id: \.self) {pastry in
Button(action: {
data.latestOrder.paId = pastry.id
}) {
Text(pastry.name)
.foregroundColor(data.latestOrder.paId == pastry.id ? .primary : .secondary)
}
}
}.listStyle(PlainListStyle())
}
}
}
The problem is your ForEach. Despite that fact that Person conforms to Identifiable, you're using \.self to identify the data. Because of that, every time an aspect of the Person changes, so does the value of self.
Instead, just use this form, which uses the id vended by Identifiable:
ForEach(data.activePersons) { person in
Which is equivalent to:
ForEach(data.activePersons, id: \.id) { person in

How to update Navigation Link subscript with an array of views inside a ForEach Loop?

I am utilizing a search bar from a Kavsoft Tutorial here: "https://www.youtube.com/watch?v=nuag1PILxCA&t=14s", I'm wondering on how to add navigation links to each of the items, I decided on embedding the itemView inside a navigation link with an array of views to loop through but it seems that it doesn't accept the index as a parameter giving "Cannot convert value of type 'item' to expected argument type 'Int'", instead I incremented the subscript on appear in the navigation link, although that updates the variable, but it doesn't seem to work for the different views themselves only navigating to the first view.
I've linked all the code needed to reproduce the problem but due to my incredibly limited experience in reproducing the problem in as less code as possible, I am not able to do so. Below the main issue of concern is the block starting from the VStack. Starting the program can be done by just adding Search_Bar() to content view body.
struct Home: View {
let views : [AnyView] = [ AnyView(untitled_Skull()), AnyView(dogs()), AnyView(cats()) ]
#Binding var filteredItems : [item]
var body: some View {
ScrollView(.vertical, showsIndicators: false) {
var i = 0
VStack(spacing: 15){
ForEach(filteredItems){index in
NavigationLink(destination: views[i]
) {
itemView(item: index)
}.onAppear() {
i = i + 1
}
}
}
.padding()
}
}
}
func add(value: Int) -> Int {
let value = value + 1
return value
}
struct itemView: View {
var item: item
#State var show = false
var body: some View {
HStack(spacing: 15){
VStack {
let colorArray: [Color] = [.yellowLichtenstien, .redHaring, .orangeBasquiat, .pinkWarhol]
HStack {
Text(item.name)
.foregroundColor(.white)
.bold()
.padding(.leading)
Spacer()
}
HStack {
Text(item.subText)
.bold()
.foregroundColor (.white)
.font(.subheadline)
.padding(.leading)
Circle()
.frame(width: 5, height: 5)
.foregroundColor(colorArray[item.color])
Text(item.subText2)
.bold()
.foregroundColor (.white)
.font(.subheadline)
Spacer()
}
Spacer()
}
}
.padding(.horizontal)
}
}
struct item: Identifiable {
var id = UUID().uuidString
// both Image And Name Are Same....
var name: String
// since all Are Apple Native Apps...
var color: Int
var subText: String
var subText2: String
}
var searchItems = [
item(name: "Untitled (Skull)", color: 0, subText: "1983", subText2: "yay"),
item(name: "Dogs", color: 1, subText: "1972", subText2: "wow"),
item(name: "Cats", color: 2, subText: "1968", subText2: "oof")
]
struct Search_Bar: View {
#State var filteredItems = searchItems
var body: some View {
CustomNavigationView(view: AnyView(Home(filteredItems: $filteredItems)), placeHolder: "Museums, Art or anything else.", largeTitle: true, title: "Search",
onSearch: { (txt) in
if txt != ""{
self.filteredItems = searchItems.filter{$0.name.lowercased().contains(txt.lowercased())}
}
else{
self.filteredItems = searchItems
}
}, onCancel: {
// Do Your Own Code When Search And Canceled....
self.filteredItems = searchItems
})
.ignoresSafeArea()
}
}
struct Search_Bar_Previews: PreviewProvider {
static var previews: some View {
Search_Bar()
}
}
import SwiftUI
struct CustomNavigationView: UIViewControllerRepresentable {
func makeCoordinator() -> Coordinator {
return CustomNavigationView.Coordinator(parent: self)
}
// Just Change Your View That Requires Search Bar...
var view: AnyView
// Ease Of Use.....
var largeTitle: Bool
var title: String
var placeHolder: String
// onSearch And OnCancel Closures....
var onSearch: (String)->()
var onCancel: ()->()
// requre closure on Call...
init(view: AnyView,placeHolder: String? = "Search",largeTitle: Bool? = true,title: String,onSearch: #escaping (String)->(),onCancel: #escaping ()->()) {
self.title = title
self.largeTitle = largeTitle!
self.placeHolder = placeHolder!
self.view = view
self.onSearch = onSearch
self.onCancel = onCancel
}
// Integrating UIKit Navigation Controller With SwiftUI View...
func makeUIViewController(context: Context) -> UINavigationController {
// requires SwiftUI View...
let childView = UIHostingController(rootView: view)
let controller = UINavigationController(rootViewController: childView)
// Nav Bar Data...
controller.navigationBar.topItem?.title = title
controller.navigationBar.prefersLargeTitles = largeTitle
// search Bar....
let searchController = UISearchController()
searchController.searchBar.placeholder = placeHolder
// setting delegate...
searchController.searchBar.delegate = context.coordinator
// setting Search Bar In NavBar...
// disabling hide on scroll...
// disabling dim bg..
searchController.obscuresBackgroundDuringPresentation = false
controller.navigationBar.topItem?.hidesSearchBarWhenScrolling = false
controller.navigationBar.topItem?.searchController = searchController
return controller
}
func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {
// Updating Real Time...
uiViewController.navigationBar.topItem?.title = title
uiViewController.navigationBar.topItem?.searchController?.searchBar.placeholder = placeHolder
uiViewController.navigationBar.prefersLargeTitles = largeTitle
}
// search Bar Delegate...
class Coordinator: NSObject,UISearchBarDelegate{
var parent: CustomNavigationView
init(parent: CustomNavigationView) {
self.parent = parent
}
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
// when text changes....
self.parent.onSearch(searchText)
}
func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
// when cancel button is clicked...
self.parent.onCancel()
}
}
}
Letting the random view below for the array being for example:
import SwiftUI
struct cats: View {
var body: some View {
Text("cats") //replacing this with dogs or untitled skull as an example.
}
}
struct cats_Previews: PreviewProvider {
static var previews: some View {
cats()
}
}
You can use ForEach getting the item and its index in the closure :
ForEach(Array(filteredItems.enumerated()), id: \.1.id) { index, item in
NavigationLink(destination: views[index]){
Text(item.name)
}
}
For example :
struct ListItem: Identifiable {
let id = UUID()
let name: String
}
struct SwiftUIView17: View {
#State private var filteredItems = ["John", "Bob", "Maria"].map(ListItem.init)
let views = [AnyView(Text("John destination")), AnyView(Text("Bob destination")), AnyView(Text("Maria destination"))]
var body: some View {
ScrollView {
ForEach(Array(filteredItems.enumerated()), id: \.1.id) { index, item in
NavigationLink(destination: views[index]){
Text(item.name)
}
}
}
}
}
But it would be better not to use AnyView but a ViewBuilder :
struct SwiftUIView17: View {
#State private var filteredItems = ["John", "Bob", "Maria"].map(ListItem.init)
#ViewBuilder func destination(for itemIndex: Int) -> some View {
switch itemIndex {
case 0: Text("John destination")
case 1: Text("Bob destination").foregroundColor(.red)
case 2: Rectangle()
default: Text("error")
}
}
var body: some View {
ScrollView {
ForEach(Array(filteredItems.enumerated()), id: \.1.id) { index, item in
NavigationLink(destination: destination(for: index)){
Text(item.name)
}
}
}
}
}

dynamic list with sections producing strange behaviour / crashes

OK, I nailed down the problem to the dynamic list with sections, so I changed the title and I'm going to shorten my post...
In my project, there is a complex view that contains a dynamic list with sections that depend on many state variables.
Problem: after a few user interactions and subsequent changes to the list, I see strange behaviour:
sometimes a section doesn't show up although the condition of the if-clause in which it is embedded is definitely met
sometimes, the section header label is replaced with the label of a list item
sometimes, it crashes
when the view is broken and I enforce a refresh of the view without changing any of the state variables, everything looks good again
The code below is taken from my project, however, greatly simplified by removing parts that are not necessary to produce the error. The state variable altered by user interaction is pIdStatus. From pIdStatus, the function data.analyze() calculates the arrays pastriesWithStatus1, pastriesWithStatus2 and pastriesWithStatus3.
Interestingly, when I remove the tab-view in which everything is embedded, everything works fine.
Any help is greatly appreciated.
import SwiftUI
struct ContentView: View {
#StateObject var data = Data()
var body: some View {
TabView { // needed in my project and needed for crash.
List {
// for debugging purpose: create a button that triggers a refresh
Button {
data.counter += 1
} label: {
HStack() {
Text("Refresh")
.font(.system(size: 16, weight: .regular))
}
}
// Section with status3-items
if data.pastriesWithStatus3.count > 0 {
Section(header:
HStack() {
Text("STATUS 3")
}
){
ForEach(data.pastriesWithStatus3, id: \.self) { i in
subview21(data: data, label: data.pastries.first(where: { $0.id == i })!.name, id: i, status: 3)
}
}
}
// section with other items
Section(header:
HStack() {
Text("OTHER ITEMS")
}
){
ForEach(data.pastriesWithStatus2, id: \.self) { i in
subview21(data: data, label: data.pastries.first(where: { $0.id == i })!.name, id: i, status: 2)
}
ForEach(data.pastriesWithStatus1, id: \.self) { i in
subview21(data: data, label: data.pastries.first(where: { $0.id == i })!.name, id: i, status: 1)
}
}
}
.listStyle(InsetGroupedListStyle())
.tabItem {
Image(systemName: "cart")
Text("shopping")
}.onAppear {
data.analyze()
}
}
}
}
struct subview21: View {
#ObservedObject var data : Data
let hspacing: CGFloat = 20
let tab1: CGFloat = 150
var label: String
var id: Int
var status: Int // 1=red, 2=unchecked, 3=green
var body: some View {
if data.testcondition { // this line is required for crash. Although it is always true.
HStack (spacing: hspacing) {
Text(data.pastries.first(where: { $0.id == id })!.name)
.frame(width: tab1, alignment: .leading)
Button {
data.pIdStatus[id] = 1
data.analyze()
} label: {
Image(systemName: (status == 1 ? "checkmark.square.fill" : "square"))
.foregroundColor(.red)
}
.buttonStyle(BorderlessButtonStyle())
Button {
data.pIdStatus[id] = 3
data.analyze()
} label: {
Image(systemName: (status == 3 ? "checkmark.square.fill" : "square"))
.foregroundColor(.green)
}
.buttonStyle(BorderlessButtonStyle())
}
}
}
}
let maxPId = 99
struct Person: Identifiable, Hashable {
let id: Int
let name: String
var orders: [Order]
}
struct Pastry: Identifiable, Hashable {
let id: Int
let name: String
}
struct Order: Hashable {
var pastryId: Int
var n: Int
var otherwise: OrderL2?
}
struct OrderL2: Hashable {
let level: Int = 2
var pastryId: Int
var n: Int
}
class Data : ObservableObject {
#Published var persons: [Person] = [
Person(id: 1, name: "John", orders: [Order(pastryId: 0, n:1, otherwise:OrderL2(pastryId: 1, n:2))]),
]
#Published var pastries: [Pastry] = [Pastry(id: 0, name: "Donut"),
Pastry(id: 1, name: "prezel")]
#Published var counter: Int = 0 // for debugging
#Published var pIdStatus: [Int] = Array(repeating: 2, count: maxPId)
#Published var testcondition: Bool = true // needed in my project, for simplicity, here, always true
#Published var pastriesWithStatus1: [Int] = []
#Published var pastriesWithStatus2: [Int] = []
#Published var pastriesWithStatus3: [Int] = []
func analyze() {
var localPastriesWithStatus1: [Int] = []
var localPastriesWithStatus2: [Int] = []
var localPastriesWithStatus3: [Int] = []
for p in pastries { // there may be more elegant ways to code, however, in real life, there's a lot more functionality here
if p.id < maxPId {
if pIdStatus[p.id] == 1 {
localPastriesWithStatus1.append(p.id)
}
if pIdStatus[p.id] == 2 {
localPastriesWithStatus2.append(p.id)
}
if pIdStatus[p.id] == 3 {
localPastriesWithStatus3.append(p.id)
}
}
}
pastriesWithStatus1 = localPastriesWithStatus1
pastriesWithStatus2 = localPastriesWithStatus2
pastriesWithStatus3 = localPastriesWithStatus3
}
}
Apparently, swiftui List is not made for Lists that are built from scratch each time the view is refreshed. Instead, Lists must be linked to arrays to/from which items are added/removed one by one.
I solved the problem by avoiding List altogether, instead using Stack, Text etc.

SwiftUI List single selectable item

I'm trying to create a List and allow only one item to be selected at a time. How would I do so in a ForEach loop? I can select multiple items just fine, but the end goal is to have only one checkmark in the selected item in the List. It may not even be the proper way to handle what I'm attempting.
struct ContentView: View {
var body: some View {
NavigationView {
List((1 ..< 4).indices, id: \.self) { index in
CheckmarkView(index: index)
.padding(.all, 3)
}
.listStyle(PlainListStyle())
.navigationBarTitleDisplayMode(.inline)
//.environment(\.editMode, .constant(.active))
}
}
}
struct CheckmarkView: View {
let index: Int
#State var check: Bool = false
var body: some View {
Button(action: {
check.toggle()
}) {
HStack {
Image("Image-\(index)")
.resizable()
.frame(width: 70, height: 70)
.cornerRadius(13.5)
Text("Example-\(index)")
Spacer()
if check {
Image(systemName: "checkmark")
.resizable()
.frame(width: 12, height: 12)
}
}
}
}
}
You'll need something to store all of the states instead of storing it per-checkmark view, because of the requirement to just have one thing checked at a time. I made a little example where the logic is handled in an ObservableObject and passed to the checkmark views through a custom Binding that handles checking/unchecking states:
struct CheckmarkModel {
var id = UUID()
var state = false
}
class StateManager : ObservableObject {
#Published var checkmarks = [CheckmarkModel(), CheckmarkModel(), CheckmarkModel(), CheckmarkModel()]
func singularBinding(forIndex index: Int) -> Binding<Bool> {
Binding<Bool> { () -> Bool in
self.checkmarks[index].state
} set: { (newValue) in
self.checkmarks = self.checkmarks.enumerated().map { itemIndex, item in
var itemCopy = item
if index == itemIndex {
itemCopy.state = newValue
} else {
//not the same index
if newValue {
itemCopy.state = false
}
}
return itemCopy
}
}
}
}
struct ContentView: View {
#ObservedObject var state = StateManager()
var body: some View {
NavigationView {
List(Array(state.checkmarks.enumerated()), id: \.1.id) { (index, item) in //<-- here
CheckmarkView(index: index + 1, check: state.singularBinding(forIndex: index))
.padding(.all, 3)
}
.listStyle(PlainListStyle())
.navigationBarTitleDisplayMode(.inline)
}
}
}
struct CheckmarkView: View {
let index: Int
#Binding var check: Bool //<-- Here
var body: some View {
Button(action: {
check.toggle()
}) {
HStack {
Image("Image-\(index)")
.resizable()
.frame(width: 70, height: 70)
.cornerRadius(13.5)
Text("Example-\(index)")
Spacer()
if check {
Image(systemName: "checkmark")
.resizable()
.frame(width: 12, height: 12)
}
}
}
}
}
What's happening:
There's a CheckmarkModel that has an ID for each checkbox, and the state of that box
StateManager keeps an array of those models. It also has a custom binding for each index of the array. For the getter, it just returns the state of the model at that index. For the setter, it makes a new copy of the checkbox array. Any time a checkbox is set, it unchecks all of the other boxes. I also kept your original behavior of allowing nothing to be checked
The List now gets an enumeration of the state.checkmarks -- using enumerated lets me keep your previous behavior of being able to pass an index number to the checkbox view
Inside the ForEach, the custom binding from before is created and passed to the subview
In the subview, instead of using #State, #Binding is used (this is what the custom Binding is passed to)
List {
ForEach(0 ..< RemindTimeType.allCases.count) {
index in CheckmarkView(title:getListTitle(index), index: index, markIndex: $markIndex)
.padding(.all, 3)
}.listRowBackground(Color.clear)
}
struct CheckmarkView: View {
let title: String
let index: Int
#Binding var markIndex: Int
var body: some View {
Button(action: {
markIndex = index
}) {
HStack {
Text(title)
.foregroundColor(Color.white)
.font(.custom(FontEnum.Regular.fontName, size: 14))
Spacer()
if index == markIndex {
Image(systemName: "checkmark.circle.fill")
.foregroundColor(Color(hex: 0xe6c27c))
}
}
}
}
}
We can benefit from binding collections of Swift 5.5.
import SwiftUI
struct CheckmarkModel: Identifiable, Hashable {
var id = UUID()
var state = false
}
class StateManager : ObservableObject {
#Published var checkmarks = [CheckmarkModel(), CheckmarkModel(), CheckmarkModel(), CheckmarkModel()]
}
struct SingleSelectionList<Content: View>: View {
#Binding var items: [CheckmarkModel]
#Binding var selectedItem: CheckmarkModel?
var rowContent: (CheckmarkModel) -> Content
#State var previouslySelectedItemNdx: Int?
var body: some View {
List(Array($items.enumerated()), id: \.1.id) { (ndx, $item) in
rowContent(item)
.modifier(CheckmarkModifier(checked: item.id == self.selectedItem?.id))
.contentShape(Rectangle())
.onTapGesture {
if let prevIndex = previouslySelectedItemNdx {
items[prevIndex].state = false
}
self.selectedItem = item
item.state = true
previouslySelectedItemNdx = ndx
}
}
}
}
struct CheckmarkModifier: ViewModifier {
var checked: Bool = false
func body(content: Content) -> some View {
Group {
if checked {
ZStack(alignment: .trailing) {
content
Image(systemName: "checkmark")
.resizable()
.frame(width: 20, height: 20)
.foregroundColor(.green)
.shadow(radius: 1)
}
} else {
content
}
}
}
}
struct ContentView: View {
#ObservedObject var state = StateManager()
#State private var selectedItem: CheckmarkModel?
var body: some View {
VStack {
Text("Selected Item: \(selectedItem?.id.description ?? "Select one")")
Divider()
SingleSelectionList(items: $state.checkmarks, selectedItem: $selectedItem) { item in
HStack {
Text(item.id.description + " " + item.state.description)
Spacer()
}
}
}
}
}
A bit simplified version
struct ContentView: View {
#ObservedObject var state = StateManager()
#State private var selection: CheckmarkModel.ID?
var body: some View {
List {
ForEach($state.checkmarks) { $item in
SelectionCell(item: $item, selectedItem: $selection)
.onTapGesture {
if let ndx = state.checkmarks.firstIndex(where: { $0.id == selection}) {
state.checkmarks[ndx].state = false
}
selection = item.id
item.state = true
}
}
}
.listStyle(.plain)
}
}
struct SelectionCell: View {
#Binding var item: CheckmarkModel
#Binding var selectedItem: CheckmarkModel.ID?
var body: some View {
HStack {
Text(item.id.description + " " + item.state.description)
Spacer()
if item.id == selectedItem {
Image(systemName: "checkmark")
.foregroundColor(.accentColor)
}
}
}
}
A version that uses internal List's selected mark and selection:
import SwiftUI
struct CheckmarkModel: Identifiable, Hashable {
var name: String
var state: Bool = false
var id = UUID()
}
class StateManager : ObservableObject {
#Published var checkmarks = [CheckmarkModel(name: "Name1"), CheckmarkModel(name: "Name2"), CheckmarkModel(name: "Name3"), CheckmarkModel(name: "Name4")]
}
struct ContentView: View {
#ObservedObject var state = StateManager()
#State private var selection: CheckmarkModel.ID?
#State private var selectedItems = [CheckmarkModel]()
var body: some View {
VStack {
Text("Items")
List($state.checkmarks, selection: $selection) { $item in
Text(item.name + " " + item.state.description)
}
.onChange(of: selection) { s in
for index in state.checkmarks.indices {
if state.checkmarks[index].state == true {
state.checkmarks[index].state = false
}
}
selectedItems = []
if let ndx = state.checkmarks.firstIndex(where: { $0.id == selection}) {
state.checkmarks[ndx].state = true
selectedItems = [state.checkmarks[ndx]]
print(selectedItems)
}
}
.environment(\.editMode, .constant(.active))
Divider()
List(selectedItems) {
Text($0.name + " " + $0.state.description)
}
}
Text("\(selectedItems.count) selections")
}
}