SwiftUI, unique stepper for items in a list view - swiftui

Question

I'm wanting to display a list of an array fetched from an NSManagedObject.
Then in that list have a stepper for each item that will eventually same the incremented amount to a property of the NSManagedObject.
My code so far:
struct ExtraIncomeAdviceView: View {
var incomes:FetchedResults<Income>
var savingsGoals:FetchedResults<SavingsGoal>
var presentationModeAddIncomeView: Binding<PresentationMode>
#Environment(\.presentationMode) var presentationModeAdvice: Binding<PresentationMode>
#State private var increment:Int = 0
var body: some View {
VStack{
Text("So you got an extra £\(String(format: "%0.2f",getLatestExtraIncome()))?").font(.headline)
VStack{
HStack{
Text("For your goals, set aside:").font(.footnote).foregroundColor(.gray)
Spacer()
}
ForEach(self.savingsGoals) { goal in
HStack{
Spacer()
Stepper("Add to \(goal.name!): \(goal.progressAmount!)", onIncrement: {
self.increment += 1
print("Adding to age")
}, onDecrement: {
self.increment -= 1
print("Subtracting from age")
})
}
}
}.padding()
.padding(.vertical, 40)
Button(action: {
self.presentationModeAdvice.wrappedValue.dismiss()
self.presentationModeAddIncomeView.wrappedValue.dismiss()
}) {
Text("Got it!")
.foregroundColor(.white)
.padding(15)
.background(Color .orange)
.cornerRadius(40)
}
}.padding()
}
}
The problem with this is that every goal thats displayed in the ForEach reads and writes to the same variable. I'm stuck on how to somehow dynamically create new variables to read and write to for each item in the array.

Answer 1

In your case, I would make a custom view struct that is called within the ForEach named GoalRow() or something applicable that contains the your HStack, Stepper, and local increment variable. Then, you can handle the stepped value appropriately within the GoalRow() struct and clean up your code a bit.
ForEach(self.savingsGoals) { goal in
GoalRow(goal: goal)
}
and then within GoalRow:
struct GoalRow: View {
var goal: YourObject
#State private var increment: Int = 0
var body: some View {
HStack(alignment: .leading, spacing: 20) {
Stepper("Add to \(goal.name!): \(goal.progressAmount!)", onIncrement: {
self.increment += 1
// edit your proposed progress amount here
print("Adding to age")
}, onDecrement: {
self.increment -= 1
// edit your proposed progress amount here
print("Subtracting from age")
})
}
Apple mentioned this in their tutorial. See the example for LandmarkRow in this tutorial Building Lists and Navigation