SwiftUI - Environment Object Not Updating UI - ios

Question

My app has one button that produces either a green or red background. The user presses the button over and over to generate green or red each time and the results are recorded into an Observable Object called "Current Session." The current totals are displayed in a custom view made of capsules. For some reason, the view will not update the totals and keeps displaying 0.
I've tried adding a state binding for numberOfGreens in ResultsBar but that doesn't work either. It still just shows 0 every time. The environment has been added to all of my views. I've tried printing the results and the result numbers show up correct in the console but the UI will not update. Interestingly, the trialsRemaining variable works perfectly on other screens in my app, having no trouble updating when it has to. Also, ResultsBar works perfectly fine in preview.
class CurrentSession: ObservableObject {
#Published var trialsRemaining: Int = 100
#Published var numberOfGreens: Int = 0
#Published var numberOfReds: Int = 0
func generateGreenOrRed() {
...
if resultIsGreen {numberOfGreens += 1}
else if resultIsRed {numberOfReds += 1}
trialsRemaining -= 1
}
}
struct ResultsBar: View {
let totalBarWidth: CGFloat = UIScreen.main.bounds.width - 48
var onePercentOfTotalWidth: CGFloat { return totalBarWidth/100 }
var numberOfGreens: Int
var body: some View {
ZStack(alignment: .leading) {
Capsule()
.frame(width: totalBarWidth, height: 36)
.foregroundColor(.red)
.shadow(radius: 4)
Capsule()
.frame(width: (onePercentOfTotalWidth * CGFloat(numberOfGreens)), height: 36)
.foregroundColor(.green)
.shadow(radius: 4)
}
}
}
struct ResultsView: View {
#EnvironmentObject var session: CurrentSession
var body: some View {
VStack {
HStack {
Text("\(session.numberOfGreens)")
Spacer()
Text("\(session.numberOfReds)")
}
ResultsBar(numberOfGreens: session.numberOfGreens)
}
}
}
I am running Xcode 11.2 beta 2 (11B44) on macOS Catalina 10.15.2 Beta (19C32e).

Answer 1

Are you passing a reference to a CurrentSession instance to your ResultsView? If I copy your code, the following does update the ResultsBar when I click on it.
struct ContentView: View {
#ObservedObject var session = CurrentSession()
var body: some View {
ResultsView()
.environmentObject(session)
.onTapGesture {
self.session.generateGreenOrRed()
}
}
}

Answer 2

I had this same issue, but my issue was because I was updating the environment object on a background thread because I'm using an api. In order to fix my issue I just needed to wrapped setting my EnvironmentObject vars like the following.
DispatchQueue.main.async{
self.numberOfGreens = GetNumberOfGreens(id: id)
}
I hope this helps someone.