Hi. I'm studying SwiftUI, an error occurred when using .sheet in SwiftUI. The code is: import SwiftUI class processStatus: ObservableObject {   @Published var isRun: Bool = false } struct Home: View {   @EnvironmentObject var startCollect: processStatus       var body: some View {     ZStack {       HomeBackgound()       VStack {         Button(action:{           self.startCollect.isRun.toggle()         }) {           VStack {             Text("あつめる")             Text("Collect")           }         }         .frame(width: 250, height: 250)       }       .sheet(isPresented: self.$startCollect.isRun) {         SelectBall()           .environmentObject(startCollect)       }     }   } } struct Home_Previews: PreviewProvider {   static var previews: some View {     Home()       .environmentObject(processStatus())   } } The error is: Thread 1: Fatal error: No ObservableObject of type processStatus found. A View.environmentObject(_:) for processStatus may be missing as an ancestor of this view. on line 23. Can anyone give me some advice? Thanks. Addendum: Added error details and error locations.