Unable to Adjust Deleted Category Totals - swiftui

Question

I have a list of 5 expense categories that the user may create and delete. When a user category is deleted, I need to subtract the category total from the grand total and the total of all user categories. Also, any user categories following after the deleted category must have the totals shifted down one position in totalArray. In C this would be a simple operation, but in SwiftUI I don't know where to begin. Can I use the index to tell what category I'm trying to delete?
The errors include "Cannot convert value of type 'IndexSet.type' to expected argument type 'Int'", and "Expression pattern of type 'Int' cannot match values of type 'IndexSet'"
Say I have all 5 categories defined. If I delete category #2 I need to shift categories 3 - 5 totals down one position to 2 - 4 totals. When the user category totals are displayed, categories.catItem.count is used to check the validity of each category total (the first one, two, three categories, etc).
// this definition is found in different file (Class UserData)
#Published var totalArray = [Double] ()
...
struct manCatView: View {
#EnvironmentObject var userData: UserData
#EnvironmentObject var categories: Categories
var body: some View {
List {
ForEach(categories.catItem) { item in
if item.noShow == false {
HStack {
Image(systemName: item.catPix).resizable()
.frame(width: 30, height: 30)
Spacer()
Text(item.catName)
}
}
}
.onDelete(perform: removeItems)
}
.navigationBarTitle(Text("Manage Categories"), displayMode: .inline)
...
func removeItems(at offsets: IndexSet) {
// at this point the deleted category still exists
// 1. must subtract 'to be deleted' category total from userTotal and grandTotal
if userData.totalArray[IndexSet] != 0 {
userData.totalArray[grandTotal] -= userData.totalArray[IndexSet]
userData.totalArray[userTotal] -= userData.totalArray[IndexSet]
}
// 2. must shift up category totals following the deleted category
switch offsets
{
case 0: // 1st category being deleted
case 1: // 2nd category being deleted
case 2: // 3rd category being deleted
case 3: // 4th category being deleted
case 4: // 5th category being deleted
default:
}
// 3. delete category
categories.catItem.remove(atOffsets: offsets)
}

Answer 1

I'm not sure if this is any better. I moved the category totals into the storage structure. In addition to deleting the category, the totals need to be adjusted first. When the user clicks delete, the removeItems function pointers are pointing to the category to be deleted. You would think that it would be easy to grab the category total (categories.catItem[].catTotal), but I get the error "Cannot convert value of type 'IndexSet' to expected argument type Int". I think Asperi that you want me to try some sort of mapping but I'm not sure where to begin.
struct CatItem: Codable, Identifiable {
var id = UUID()
var catNum: Int // entryView category pointer
var catName: String // category name
var catTotal: Double // category total
var catPix: String // sf symbol
var catShow: Bool // don't show certain categories
}
class Categories: ObservableObject {
#Published var catItem: [CatItem] {
}
}
...
struct manCatView: View {
#EnvironmentObject var userData: UserData
#EnvironmentObject var categories: Categories
var pic: String = ""
var body: some View {
List {
ForEach(categories.catItem) { index in
if index.catShow == true {
HStack {
let pic = categories.catItem[index].catPix
Image(systemName: pic)
.resizable()
.foregroundColor(Color(colors[index]))
.frame(width: 40, height: 40)
Text("")
.frame(width: 40, alignment: .leading)
Text(index.catName)
}
}
} // end foreach
.onDelete(perform: removeItems)
} // end list
.navigationBarTitle(Text("Manage Categories"), displayMode: .inline)
}
func removeItems(at offsets: IndexSet) {
//subtract category amount from system totals.
let catTotal = categories.catItem[offsets].catTotal // <-- error here
userData.totalArray[grandTotal] -= catTotal
userData.totalArray[userTotal] -= catTotal
categories.catItem.remove(atOffsets: offsets)
}
}