SwiftUI Save New Object and Navigate to it - swift

Question

When the NavigationLink is pressed I want to create an object (with the time when it was pressed), add it to the savedObjects and pass then new object to the destination view.
How can I do this without changing the state while the view is updating?
struct ContentView: View {
#State private var savedObjects = [
MyObject(
id: 0,
date: Date()
),
MyObject(
id: 1,
date: Date()
),
MyObject(
id: 2,
date: Date()
),
MyObject(
id: 3,
date: Date()
)
]
var body: some View {
NavigationView {
List {
NavigationLink("Save new object and navigate to it", destination: DestinationView(object: MyObject(id: Int.random(in: 10...1000), date: Date())))
ForEach(savedObjects) { object in
NavigationLink("Navigate to object \(object.id)", destination: DestinationView(object: object))
}
}
}
}
}
class MyObject: ObservableObject, Identifiable {
var id: Int
var date: Date
init(id: Int, date: Date) {
self.id = id
self.date = date
}
}
struct DestinationView: View {
#ObservedObject var object: MyObject
var body: some View {
VStack {
Text("object \(object.id)")
Text("date: \(object.date.description)")
}
}
}

Answer 1

Here is a solution that refreshes state with a new Date when the link appears.
struct LinkWithPayloadView: View {
#State private var date = Date()
var body: some View {
NavigationView {
navigationLink(payload: "Cookies and Milk", date: date)
.onAppear(perform: {
date = Date()
})
}
}
func navigationLink(payload: String, date: Date) -> some View {
let formatter = DateFormatter()
formatter.dateFormat = "HH:mm:ss"
let payload = Payload(timestamp: date, inners: payload)
let vstack = VStack {
Text("\(payload.inners)")
Text("\(formatter.string(from: payload.timestamp))")
}
return NavigationLink(payload.inners, destination: vstack)
}
struct Payload {
let timestamp : Date
let inners : String
}
}
Credit #mallow for the idea

Answer 2

My question is why can't you make a separate destination view to save the object? Then you don't need to worry about saving it in the starting view.
struct DestinationView: View {
#Environment(\.managedObjectContext) var managedObjectContext
#ObservedObject var object: MyObject
init(id : Int, date : Date) {
let myObject = MyObject(context: managedObjectContext)
myObject.date = date
myObject.id = id
try! managedObjectContext.save()
self.object = myObject
}
var body: some View {
VStack {
Text("object \(object.id)")
Text("date: \(object.date.description)")
}
}
}
Then you can just reload the objects from coredata when the navigation closes.

Answer 3

I think programmatic navigation is the best solution in my case. So clicking a different button that creates and saves the object which in turn creates a new NavigationLink and then initiating the navigation immediately as explained here:
https://www.hackingwithswift.com/quick-start/swiftui/how-to-use-programmatic-navigation-in-swiftui