I’m struggling with the following issue: I’m trying to build a very simple app that lets you add items in a dedicated view that can be collapsed. I managed to write a simple function that lets me add multiple of these custom collapsable views. It’s my first app so I wanted to follow the MVVM protocol. I think I got confused along the way because now every item I add gets automatically added to all the custom collapsable views I made. Is there any way to fix this? I thought using the UUID would solve this issue.. I’m guessing that I have to customise the "saveButtonPressed" function, but I don’t know how to tell it to only add the item to the view where I pressed the "plus" button..
Here are the Models for the individual items and the collapsable view:
struct ItemModel: Identifiable, Equatable {
let id: String
let title: String
init(id: String = UUID().uuidString, title: String) {
self.id = id
self.title = title
}
func updateCompletion() -> ItemModel {
return ItemModel(id: id, title: title)
}
}
—
import Foundation
struct CollapsableItem: Equatable, Identifiable, Hashable {
let id: String
var title: String
init(id: String = UUID().uuidString, title: String) {
self.id = id
self.title = title
}
func updateCompletion() -> CollapsableItem {
return CollapsableItem(id: id, title: title)
}
}
These are my two ViewModels:
class ListViewModel: ObservableObject {
@Published var items: [ItemModel] = []
init() {
getItems()
}
func getItems() {
let newItems = [
ItemModel(title: "List Item1"),
ItemModel(title: "List Item2"),
ItemModel(title: "List Item3"),
]
items.append(contentsOf: newItems)
}
func addItem(title: String) {
let newItem = ItemModel(title: title)
items.append(newItem)
}
func updateItem(item: ItemModel) {
if let index = items.firstIndex(where: { $0.id == item.id}) {
items[index] = item.updateCompletion()
}
}
}
—
class CollapsedViewModel: ObservableObject {
@Published var collapsableItems: [CollapsableItem] = []
@Published var id = UUID().uuidString
init() {
getCollapsableItems()
}
func getCollapsableItems() {
let newCollapsableItems = [
CollapsableItem(title: "Wake up")
]
collapsableItems.append(contentsOf: newCollapsableItems)
}
func addCollapsableItem(title: String) {
let newCollapsableItem = CollapsableItem(title: title)
collapsableItems.append(newCollapsableItem)
}
func updateCollapsableItem(collapsableItem: CollapsableItem) {
if let index = collapsableItems.firstIndex(where: { $0.id ==
collapsableItem.id}) {
collapsableItems[index] =
collapsableItem.updateCompletion()
}
}
}
The item view:
struct ListRowView: View {
@EnvironmentObject var listViewModel: ListViewModel
let item: ItemModel
var body: some View {
HStack() {
Text(item.title)
.font(.body)
.fontWeight(.bold)
.foregroundColor(.white)
.multilineTextAlignment(.center)
.lineLimit(1)
.frame(width: 232, height: 16)
}
.padding( )
.frame(width: 396, height: 56)
.background(.gray)
.cornerRadius(12.0)
}
}
The collapsable view:
struct CollapsedView2<Content: View>: View {
@State var collapsableItem: CollapsableItem
@EnvironmentObject var collapsedViewModel: CollapsedViewModel
@State private var collapsed: Bool = true
@EnvironmentObject var listViewModel: ListViewModel
@State var label: () -> Text
@State var content: () -> Content
@State private var show = true
var body: some View {
ZStack{
VStack {
HStack{
Button(
action: { self.collapsed.toggle() },
label: {
HStack() {
Text("Hello")
.font(.title2.bold())
Spacer()
Image(systemName: self.collapsed ? "chevron.down" :
"chevron.up")
}
.padding(.bottom, 1)
.background(Color.white.opacity(0.01))
}
)
.buttonStyle(PlainButtonStyle())
Button(action: saveButtonPressed, label: {
Image(systemName: "plus")
.font(.title2)
.foregroundColor(.white)
})
}
VStack {
self.content()
}
ForEach(listViewModel.items) { item in ListRowView (item: item)
}
.lineLimit(1)
.fixedSize(horizontal: true, vertical: true)
.frame(minWidth: 396, maxWidth: 396, minHeight: 0, maxHeight: collapsed ?
0 : .none)
.animation(.easeInOut(duration: 1.0), value: show)
.clipped()
.transition(.slide)
}
}
}
func saveButtonPressed() {
listViewModel.addItem(title: "Hello")
}
}
and finally the main view:
struct ListView: View {
@EnvironmentObject var listViewModel: ListViewModel
@EnvironmentObject var collapsedViewModel: CollapsedViewModel
var body: some View {
ZStack{
ScrollView{
VStack{
HStack{
Text("MyFirstApp")
.font(.largeTitle.bold())
Button(action: newCollapsablePressed, label: {
Image(systemName: "plus")
.font(.title2)
.foregroundColor(.white)
})
}
.padding()
.padding(.leading)
ForEach(collapsedViewModel.collapsableItems) { collapsableItem in
CollapsedView2 (collapsableItem: collapsableItem,
label: { Text("") .font(.title2.bold()) },
content: {
HStack {
Text("")
Spacer() }
.frame(maxWidth: .infinity)
})
}
.padding()
}
}
.frame(maxWidth: .infinity, maxHeight: .infinity)
.statusBar(hidden: false)
.navigationBarHidden(true)
}
}
func newCollapsablePressed() {
collapsedViewModel.addCollapsableItem(title: "hello2")
}
}
Would love to understand how I could fix this!
2
Answers
There is the anwser. Ask me if you have some questions
There is the anwser for your comment about add item in each CollapsedView2.
Because ListViewModel is not ObservableObject (ListViewModel is difference from each CollapsableItem). You should use "@State var items: [ItemModel]".