How to replace #FetchRequest by dynamic call - swiftui

Question

I have this code in my SwiftUI project in works well
struct ContentView: View {
#State private var selectedCountry: Country?
#State private var showSetting = false
#FetchRequest(entity: Country.entity(),
sortDescriptors: [NSSortDescriptor(keyPath: \Country.cntryName, ascending: true)]
) var countries: FetchedResults<Country>
var body: some View {
NavigationView {
VStack {
Form {
Picker("Pick a country", selection: $selectedCountry) {
ForEach(countries, id: \Country.cntryName) { country in
Text(country.cntryName ?? "Error").tag(country as Country?)
}
}
if selectedCountry != nil {
DetailView(cntryName: (selectedCountry?.cntryName!)!)
}
}
}
.navigationBarTitle("UNECE Data")
.navigationBarItems(trailing: Button("Settings", action: {
self.showSetting.toggle()
}))
}
.sheet(isPresented: $showSetting) {
SettingsView(showSetting: self.$showSetting)
}
}
}
However I need to call FetchRequest dynamically end reload Picker view when SettingsView dismiss. Possibly I should use #ObservableObject but how to put there fetch request and use result in the Picker view ForEach? Thanks for hints.

Answer 1

You can customize most part of your FetchRequest:
#FetchRequest(entity: Country.entity(),
sortDescriptors: ObservableObject.sortDesc,
predicate : ObservableObject.predicate
) var countries: FetchedResults<Country>

Answer 2

I have reworked code like this
var body: some View {
NavigationView {
VStack {
Form {
//Text(String(describing: countries.count))
Picker("Pick a country", selection: $selectedCountry) {
ForEach(getAllCountries().wrappedValue, id: \Country.cntryName) { country in
Text(country.cntryName ?? "Error").tag(country as Country?)
}
}
if selectedCountry != nil {
DetailView(cntryName: (selectedCountry?.cntryName!)!)
}
}
}
.navigationBarTitle("UNECE Data")
.navigationBarItems(trailing: Button("Settings", action: {
self.showSetting.toggle()
}))
}
.sheet(isPresented: $showSetting) {
SettingsView(showSetting: self.$showSetting)
}
}
func getAllCountries() -> FetchRequest<Country> {
let request = FetchRequest<Country>(entity: Country.entity(),
sortDescriptors: [NSSortDescriptor(keyPath: \Country.cntryName, ascending: true)])
return request
}
but it reports fatal error "Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" on ForEach line when runs.

Answer 3

In SettingsView I delete all data in Country entity, parse JSON file stored on my iCloud and save all data in Country entity.