Swift Struct in Array of Structs not updating to new values - arrays

Question

This is my data structure
struct SPPWorkout: Codable {
static let setKey = "Sets"
static let exerciseID = "id"
var id: Double? = 0.0
var duration: String?
var calories: Int?
var date: String?
var exercises: [ExerciseSet]
[...]
}
struct ExerciseSet: Codable {
let id: String
let name: String
var reps: Int
var weight: Double
[...]
}
extension ExerciseSet: Equatable {
static func ==(lhs: ExerciseSet, rhs: ExerciseSet) -> Bool {
return lhs.id == rhs.id
}
}
and in a SwiftUI view I'm trying to modify an ExerciseSet from user input
#State private var sppWorkout: SPPWorkout!
EditSetPopup(isShowingOverlay: $isShowingOverlay,
update: { reps, weight in
guard let editingIndex = editingIndex else { return }
sppWorkout.exercises[editingIndex].reps = Int(reps) ?? 0
sppWorkout.exercises[editingIndex].weight = Double(weight) ?? 0.0
self.editingIndex = nil
})
}
The issue is here
sppWorkout.exercises[editingIndex].reps = Int(reps) ?? 0
sppWorkout.exercises[editingIndex].weight = Double(weight) ??
and I've tried in all ways to update it, both from the view and with a func in SPPWorkout. I've also tried to replace the object at index
var newSet = ExerciseSet(id: [...], newValues)
self.exercises[editingIndex] = newSet
but in no way it wants to update. I'm sure that somewhere it creates a copy that it edits but I have no idea why and how to set the new values.
Edit: if I try to delete something, it's fine
sppWorkout.exercises.removeAll(where: { $0 == sppWorkout.exercises[index]})
Edit 2:
It passes the guard statement and it does not change the values in the array.
Edit 3:
At the suggestion below from Jared, I've copied the existing array into a new one, set the new values then tried to assign the new one over to the original one but still, it does not overwrite.
EditSetPopup(isShowingOverlay: $isShowingOverlay,
update: { reps, weight in
print(sppWorkout.exercises)
guard let editingIndex = editingIndex else { return }
var copyOfTheArray = sppWorkout.exercises
copyOfTheArray[editingIndex].reps = Int(reps) ?? 0
copyOfTheArray[editingIndex].weight = Double(weight) ?? 0.0
//Copy of the array is updated correctly, it has the new values
sppWorkout.exercises = copyOfTheArray
//Original array doesn't get overwritten. It still has old values
self.editingIndex = nil
Edit 4: I've managed to make progress by extracting the model into a view model and updating the values there. Now the values get updated in sppWorkout, but even though I call objectWillChange.send(), the UI Update doesn't trigger.
full code:
class WorkoutDetailsViewModel: ObservableObject {
var workoutID: String!
#Published var sppWorkout: SPPWorkout!
func setupData(with workoutID: String) {
sppWorkout = FileIOManager.readWorkout(with: workoutID)
}
func update(_ index: Int, newReps: Int, newWeight: Double) {
let oldOne = sppWorkout.exercises[index]
let update = ExerciseSet(id: oldOne.id, name: oldOne.name, reps: newReps, weight: newWeight)
sppWorkout.exercises[index] = update
self.objectWillChange.send()
}
}
struct WorkoutDetailsView: View {
var workoutID: String!
#StateObject private var viewModel = WorkoutDetailsViewModel()
var workout: HKWorkout
var dateFormatter: DateFormatter
#State private var offset = 0
#State private var isShowingOverlay = false
#State private var editingIndex: Int?
#EnvironmentObject var settingsManager: SettingsManager
#Environment(\.dismiss) private var dismiss
var body: some View {
if viewModel.sppWorkout != nil {
VStack {
ListWorkoutItem(workout: workout, dateFormatter: dateFormatter)
.padding([.leading, .trailing], 10.0)
List(viewModel.sppWorkout.exercises, id: \.id) { exercise in
let index = viewModel.sppWorkout.exercises.firstIndex(of: exercise) ?? 0
DetailListSetItem(exerciseSet: viewModel.sppWorkout.exercises[index], set: index + 1)
.environmentObject(settingsManager)
.swipeActions {
Button(role: .destructive, action: {
viewModel.sppWorkout.exercises.removeAll(where: { $0 == viewModel.sppWorkout.exercises[index]})
} ) {
Label("Delete", systemImage: "trash")
}
Button(role: .none, action: {
isShowingOverlay = true
editingIndex = index
} ) {
Label("Edit", systemImage: "pencil")
}.tint(.blue)
}
}
.padding([.leading, .trailing], -30)
//iOS 16 .scrollContentBackground(.hidden)
}
.overlay(alignment: .bottom, content: {
editOverlay
.animation(.easeInOut (duration: 0.5), value: isShowingOverlay)
})
.navigationBarBackButtonHidden(true)
.navigationBarItems(leading: Button(action : {
do {
try FileIOManager.write(viewModel.sppWorkout, toDocumentNamed: "\(viewModel.sppWorkout.id ?? 0).json")
} catch {
Debugger.log(error: error.localizedDescription)
}
dismiss()
}){
Image(systemName: "arrow.left")
})
} else {
Text("No workout details found")
.italic()
.fontWeight(.bold)
.font(.system(size: 35))
.onAppear(perform: {
viewModel.setupData(with: workoutID)
})
}
}
#ViewBuilder private var editOverlay: some View {
if isShowingOverlay {
ZStack {
Button {
isShowingOverlay = false
} label: {
Color.clear
}
.edgesIgnoringSafeArea(.all)
VStack{
Spacer()
EditSetPopup(isShowingOverlay: $isShowingOverlay,
update: { reps, weight in
guard let editingIndex = editingIndex else { return }
print(viewModel.sppWorkout.exercises)
print("dupa aia:\n")
viewModel.update(editingIndex, newReps: Int(reps) ?? 0, newWeight: Double(weight) ?? 0.0)
print(viewModel.sppWorkout.exercises)
self.editingIndex = nil
})
.overlay(
RoundedRectangle(cornerRadius: 10)
.stroke(Color("popupBackground"),
lineWidth: 3)
)
}
}
}
}
}

Answer 1

So I got a very good explanation on reddit on what causes the problem. Thank you u/neddy-seagoon if you are reading this.
The explanation
. I believe that updating an array will not trigger a state update. The only thing that will, with an array, is if the count changes. So
sppWorkout.exercises[index].reps = newReps
will not cause a trigger. This is not changing viewModel.sppWorkout.exercises.indices
So all I had to to was modify my List from
List(viewModel.sppWorkout.exercises, id: \.id)
to
List(viewModel.sppWorkout.exercises, id: \.hashValue)
as this triggers the list update because the hashValue does change when updating the properties of the entries in the list.

Answer 2

For the line
List(viewModel.sppWorkout.exercises, id: \.id) { exercise in
Replace with
List(viewModel.sppWorkout.exercises, id: \.self) { exercise in