SwiftUI update observedObject in Cell View of list - swiftui

Question

I tried to change the value of the observedObject. The value will changed but not permanently. When I scroll down and scroll back, the value will changed back to original value. I guess is the problem of #State in the cell view of list. But I cant figure out what the solution to change the data permanently in observedObject. So what should I do to change the data permanently by using the data cell.
struct ContentView: View {
#ObservedObject var dataClass = DataClass()
var body: some View {
List(dataClass.data){ item in
DataCell(item: item)
}
}
}
struct DataCell: View {
#State var item : DataModal
var body: some View{
HStack{
Text("\(item.num!)")
Text("\(item.val!)").onTapGesture {
item.val = 1
}
}
.padding(.vertical, 100)
}
}
struct DataModal : Identifiable {
var id = UUID()
var num : Int?
var val : Int?
}
class DataClass : ObservableObject {
#Published var data = [DataModal]()
init(){
load()
}
func load(){
data = [DataModal(num: 1, val: 1),DataModal(num: 2, val: 2),DataModal(num: 3, val: 3),DataModal(num: 4, val: 4),DataModal(num: 5, val: 5),DataModal(num: 6, val: 6),DataModal(num: 7, val: 7),DataModal(num: 8, val: 8),DataModal(num: 9, val: 9),DataModal(num: 10, val: 10),DataModal(num: 11, val: 11),DataModal(num: 12, val: 12),DataModal(num: 13, val: 13)]
}
}

Answer 1

You pass a copy of DataModal, because it is a value type. In this scenario you need to pass binding to original value inside dataClass, like
struct ContentView: View {
#ObservedObject var dataClass = DataClass()
var body: some View {
List(dataClass.data.indices, id: \.self){ index in
DataCell(item: $dataClass.data[index])
}
}
}
struct DataCell: View {
#Binding var item : DataModal
var body: some View{
HStack{
Text("\(item.num!)")
Text("\(item.val!)").onTapGesture {
item.val = 1
}
}
.padding(.vertical, 100)
}
}