SwiftUI persist observable objects - swift

Question

I am trying to understand data flows in swiftUI.
I have created a ViewModel which holds some data from a network request.
import SwiftUI
struct breakdown: Decodable {
var sms: Int
var im: Int
var total: Int
}
struct weeklyOverviewStruct: Decodable {
var data: [breakdown]
}
class WeeklyOverviewViewModel: ObservableObject {
#Published var overviewData: weeklyOverviewStruct?
func getBreakdown(){
semaphore.wait()
Network.Request(method: .GET , parameters: nil, endPoint: "rest/operator/stats/weekly/breakdown", completion: {
result,error in
if(error == nil){
do {
let breakdown = try JSONDecoder().decode(weeklyOverviewStruct.self, from: result!)
DispatchQueue.main.async {
self.overviewData = breakdown
}
}catch{
print("Json Error")
}
}else{
print("\(error!)")
}
})
}
}
It my understanding that I can then observe this ViewModel in a second view and the view will re-draw if the ViewModel changes:
struct SecondView: View {
#ObservedObject var WeeklyOverviewVM = WeeklyOverviewViewModel()
var body: some View {
Text(String.init(describing: WeeklyOverviewVM.overviewData?.data[0].total))
}
}
If however the second view is presented after the getBreakDown() is called the observedObject is nil.
Is there a way of persisting the data so that even if a view is presented after the getBreakdown() function is called, the data from the previous request is observable in the second view?

Answer 1

The SecondView now creates view model every time it is instantiated, so if you want previously fetched data persist, it needs to store that view model instance somewhere outside of SecondView and inject it on its creation, like
struct SecondView: View {
// only declare
#ObservedObject var WeeklyOverviewVM: WeeklyOverviewViewModel
and somewhere in parent view
...
// inject WeeklyOverviewViewModel from own property
SecondView(WeeklyOverviewVM: self.secondViewVM)
...