カレンダーのアクセスなければダイアログ表示

こんな感じか

swift

  .sheet(isPresented: $appData.dispRequestAccessDialog) {
   appData.updateRequestStatus() // onDismiss
  } content: {
   VStack {
    Text("Allow access to calendar")
    Text("description ...")
    
    if appData.authStatus == .denied {
     Link("Open App Settings", destination: URL(string: UIApplication.openSettingsURLString)!)
    } else {
     Button("Request Access") {
      requestAccess()
     }
    }
   }
  }
  .onAppear {
   requestAccess()
  }
  .onChange(of: scenePhase) { _, newPhase in
   if newPhase == .active {
    appData.resetValues()
   }
  }

 func requestAccess() {
  EventKitUtil.requestAccess(to: .event) { (granted: Bool, error: Error?) in
   appData.updateRequestStatus()
   if let error = error {
    print(error)
   }
  }
 }

swift

class ApplicationData: ObservableObject {
	var authStatus: EKAuthorizationStatus = .notDetermined
	var dispRequestAccessDialog: Bool = false
	...

	func updateRequestStatus() {
		authStatus = EventKitUtil.getAuthorizationStatus(for: .event).status
		dispRequestAccessDialog = authStatus != .fullAccess
	}
}