Refreshing UserDefaults Variable not working - swift

Question

I have a navigation view that uses User defaults, when I am on a different page I have a button that adds += 1 to the userDefualts variable. When I go back there, it doesn't refresh unless I swipe the app. That is super weird, what I want to happen is it automatically refreshes when I enter that page.
Nav View that I need refreshed:
struct Analytics: View {
#ObservedObject var viewModel = VariableViewModel()
HStack {
// Problems compleated
Text(" Amount of problems compleated:")
.font(.system(size: 20))
.foregroundColor(.black)
Spacer()
Text(String(viewModel.problemsCompleated))
.font(.system(size: 20))
.foregroundColor(.yellow)
.bold()
.offset(x: -5, y: 0)
}.offset(x: 0, y: 5)
}
Nav View were the variables sit and are being changed:
class VariableViewModel: ObservableObject {
// analytics
#Published var problemsCompleated = UserDefaults.standard.integer(forKey: "problemsCompleated")
problemsCompleated += 1
UserDefaults.standard.set(problemsCompleated, forKey: "problemsCompleated")
}

Answer 1

With your current code, if you're using different instances of VariableViewModel, you won't see it refresh because it only ever pulls from UserDefaults on instantiation. So, when you go 'back' to the other page, it has no way of knowing that variable has been updated.
If you were just within your view, I'd recommend using #AppStorage, since it does all the lifting of checking and updating UserDefaults for you. In the ObservableObject, it's slightly more complicated, because #AppStorage won't trigger an update like #Published. But, it looks like by manually calling objectWillChange when the #AppStorage is set, we can get the best of both worlds:
class VariableViewModel: ObservableObject {
#AppStorage("problemsCompleted") var problemsCompleted = 0 {
didSet {
self.objectWillChange.send()
}
}
func increment() {
problemsCompleted += 1
}
}