SwiftUI ForEach loop does not reflect changes when the list changes state?

I am still trying to understand exactly how @State, @ObservedObject, @Published, etc properties can help accomplish what I am trying to do. I have tried a variety of these in different ways with no change in my issue.

So right now I have two @State variables along with this for loop within my main view. The loop displays the views stored within the eventViews list with the frame and position specified in the eventBounds list.

struct CalendarDayView: View { 
    @State var eventViews: [CalendarEventView] = [] 
    @State var eventBounds: [CGRect] = [] 
    var body: some View { 
        ZStack { 
            ForEach(eventViews.indices, id: \.self) { index in     
                let eventView = eventViews[index] 
                let bounds =   eventBounds[index] 
                eventView          
                    .frame(width: bounds.width, 
                        height: bounds.height, 
                        alignment: .center) 
                    .position(x: bounds.midX, y: bounds.midY) 
            } 
        } 
    }                
}

When the user makes changes to the events or their bounds I call a function calculateEventBounds() which goes through all the events and calculates the bounds I want them to be rendered with according to their positioning, etc. Everything works great, except when I call calculateEventBounds(), the changes made are only updated on the UI after I switch tabs on my app and go back to the CalendarDayView. I need the changes to be seen immediately after calling calculateEventBounds().

How can I invalidate this for loop so that the changes to eventViews and eventBounds are seen immediately in the UI?

Here is simplified code for calculateEventBounds():

func calculateEventBounds() { 
    self.eventViews = [] 
    self.eventBounds = [] 
    let events = eventsManager.getEventsOnDay(day: Int(day))         
    
    for event in events { //do fancy stuff to calculate the event's bounds 
        self.eventViews.append(CalendarEventView(event: event))   
        self.eventBounds.append(bounds) //bounds is a CGRect defined within the for loop 
    }
}

My struct CalendarEventView is a view that holds a CalendarEvent struct with the info of the CalendarEvent like it's name, start time, etc.

I've tried using a separate class that conforms to ObservableObject and holds the eventViews and eventBounds as @Published properties while storing that class as an @ObservedObject in my CalendarDayView, and the for loop would get the views from a getter function of the other class but that didn't solve my issue either.

There are two major bad practices, I even call them mistakes:

1. Multiple arrays as data source
2. SwiftUI view as part of the data source.

An event should be an Event struct containing the bounds, an init method for the event data and the method to calculate the bounds (is a grid or another intelligent collection view not a better choice?).

struct Event: Identifiable {
    let id = UUID()
    var bounds: CGRect = .zero 

    init(data: ...) { ... }

    calculateBounds() { ... }
}

Then use a View Model, a class conforming to ObservableObject – as you already tried – with a @Published property containing the events, and also a method to get the events and create Event instances

class EventManager: ObservableObject {
    @Published var events = [Event]()

    func getEventsOnDay(day: Int) { 
       
        let eventData = // get the data        
        events = eventData.map { data in
            let event = Event(data: data)
            event.calculateBounds()
            return event
        }
    }
}

In the view create an instance of EventManager as @StateObject and get the events from there.

struct CalendarDayView: View { 
    @StateObject var manager = EventManager()
   
    var body: some View { 
        ZStack { 
            ForEach(manager.events) { event in
                let bounds = event.bounds 
                CalendarEventView(event: event)         
                    .frame(width: bounds.width, 
                        height: bounds.height, 
                        alignment: .center) 
                    .position(x: bounds.midX, y: bounds.midY) 
            } 
        } 
    }                
}

In onAppear (or in asynchronous task) you can call the method to get the data.

Any change in the events array will trigger the view to refresh.