how to use EnvironmentObject in a Swiftui View function? - ios

Question

Resolved
Finally, I found the problem. My questioned View was placed in a .sheet. If I show this View separately, the environment variables will work, but if they are placed in .sheet, the Store must be explicitly injected in.
.sheet(isPresented: $showEditSheet){
EditFavoriteRootView().environmentObject(Store())
}
Now It's worked!
old quesition
Because ForEach couldn't support too complicated logic, I defined a function in the View to implement the content.
In most cases, this is fine. However, I cannot use the EnviromentObject in the function。
build success , the button in View body works fine, but when I click button in function got the runtime error:
Fatal error: No ObservableObject of type Store found.
A View.environmentObject(_:) for Store may be missing as an ancestor of this view.: file /BuildRoot/Library/Caches/com.apple.xbs/Sources/Monoceros/Monoceros-
Code sample:
struct FromCategory: View {
#EnvironmentObject var store:Store
var body: some View {
ForEach(AppState.HealthCategoryList.keys.sorted(by: <),id:\.self){
self.ShowList(categoryId: $0)
}
Button(action:{
self.store.dispatch(.updateFavorite(idName:"test"))
}){Text("Test")}
}
func ShowList(categoryId:String)->some View{
let metalist = AppState.HealthCategoryList[categoryId]?.metaData?.sortedArray(using: [NSSortDescriptor(key: "idName", ascending: true)]) as! [HealthMetaData]
return VStack{
VStack(spacing:10) {
ForEach(0..<metalist.count){i in
HStack{
Text(metalist[i].title!)
Spacer()
Button(action:{
self.store.dispatch(.updateFavorite(idName: metalist[i].idName!))
//self.store.appState.updateFavorite(idName: metalist[i].idName!)
}){
if AppState.UserFavoriteList[metalist[i].idName!] != nil {
Image(systemName: "star.fill")
}
else {
Image(systemName: "star")
}
}
}
}
}
}
}
}
Fatal error: No ObservableObject of type Store found. in this line
self.store.dispatch(.updateFavorite(idName: metalist[i].idName!))
store can be use well in normal some View, but not in function.
How to solve this. Or is there any other way?
Thanks

Answer 1

This is happening because you want to update an EnvironmentObject and you're not in the View which was loaded by the SceneDelegate.swift
In case you're using the EnvObject in a correct way, you just need to pass te EnvObject to the next view like this:
DestinationView().environmentObject(self.yourEnvObject)
More information explained in my post:
https://stackoverflow.com/a/58997326/12378791