Strange behavior of #Binding variable in SwiftUI integrating UIKit (iOS app) - swift

Question

I am developing an App for my school's courses, displaying the descriptions of the courses as well as a calendar showing the appointments. I decided to use KVKCalendar as a library for the Calendar. Developing with SwiftUI and being the KVKCalendar library a UIKit environment, I had to interface the two systems (with the struct CalendarRepresentable, see code).
The app is constructed as follow: I load from the memory an #ObservedObject with the saved objects, pass it to some sub-views as #Binding in order to save/delete new courses from the course-catalogue.
All changes made in the views are updated accordingly in all the other views, but unfortunately not in the TimetableView, connected with the struct CalendarRepresentable.
The problem: I want to update the Calendar whenever new courses are saved (e.g. added to the array courses of the type [Courses]). At the moment the struct CalendarRepresentable is calling the makeUIView as expected but the calendar is not updated anymore. In particular the saved courses in courses are not constantly updated but in a (apparently) inconsitent way: in some functions of the struct CalendarRepresentable are indeed up to date, in some other functions (and subclasses) not. See code where I show where and in what case these inconsistencies occure.
Code of the View calling the UIKit-SwiftUI interface:
import SwiftUI
import KVKCalendar
struct TimetableView: View {
#Binding var courses: [Courses]
let saveAction: () -> Void
var body: some View {
CalendarRepresentable(courses: $courses)
}
}
struct TimetableView_Previews: PreviewProvider {
static var previews: some View {
TimetableView(courses: .constant(Courses.data), saveAction: {})
}
}
Code of the interface:
import SwiftUI
import KVKCalendar
import EventKit
struct CalendarRepresentable: UIViewRepresentable{
#Binding var courses: [Courses]
var events = [Event]()
var calendar: CalendarView = {
print("Representable has been launched")
var style = Style()
//style of the calendar
//...
return CalendarView(frame: UIScreen.main.bounds, style: style)
}()
func updateUIView(_ uiView: CalendarView, context: Context ){
print("updateUIView has been called. Courses has \(courses.count) elements") // **Here courses has always the correct amount of elements**
calendar.dataSource = context.coordinator
calendar.delegate = context.coordinator
calendar.reloadData()
calendar.reloadInputViews()
print("updateUIView is finished")
}
public func passCourses() -> [Courses]{
print("Called passCourses with courses having \(courses.count) elements") //**Here courses has NOT the corrent amount of elements, i.e. after saving/deleting a course courses.count is different from what is printed in the previous function updateUIView**
return courses
}
func makeUIView(context: Context) -> CalendarView {
print("makeUIView has been called")
calendar.dataSource = context.coordinator
calendar.delegate = context.coordinator
calendar.reloadData()
return calendar
}
func makeCoordinator() -> Coordinator {
print("makeCoordinator")
return Coordinator(self)
}
class Coordinator: NSObject, CalendarDelegate, CalendarDataSource {
var events = [Event]()
var parent: CalendarRepresentable
func eventsForCalendar(systemEvents: [EKEvent]) -> [Event] {
print("eventsForCalendar called. In Coordinator \(events.count) events and \(parent.courses.count) courses") //**here courses are again not uptodate to the CalendarRepresentable' courses**
loadEvents { (events) in
self.events = events
}
return self.events
}
init(_ parent: CalendarRepresentable){
print("Initialize Coordinator")
self.parent = parent
super.init()
loadEvents { (events) in
self.events = events
self.parent.calendar.reloadData()
}
}
func eventsForCalendar() -> [Event] {
print("eventsForCalendar without parameter")
return events
}
func loadEvents(completion: ([Event]) -> Void) {
var events = [Event]()
print("loadEvents with courses having \(self.parent.courses.count) elements")//**here courses are again not uptodate to the CalendarRepresentable' courses**
var i: Int=0
for course in self.parent.passCourses() {
let isoDateStart = course.startEvent
let dateStartFormatter = ISO8601DateFormatter()
let isoDateEnd = course.endEvent
let dateEndFormatter = ISO8601DateFormatter()
var event = Event(ID: "\(i)")
event.start = dateStartFormatter.date(from: isoDateStart)!
event.end = dateEndFormatter.date(from: isoDateEnd)!
event.text = course.name
events.append(event)
i=i+1
}
completion(events)
}
}
}
Example of console output after saving a course (done in another view) with (apparent) inconsistency:
Representable has been launched
updateUIView has been called. Courses has 4 elements
eventsForCalendar called. In Coordinator 3 events and 3 courses
loadEvents with courses having 3 elements
Called passCourses with courses having 3 elements
updateUIView is finished
Does anyone know what is happening to courses? Suggestions on how should I solve the issue?
Thanks a lot for your time and help!

Answer 1

After extensive testing I found that the problem was that somehow the coordinator had been called with an old parent although the outerstruct had been changed. I am not sure about the internal cause of that behavior, but anyway it should now be solved: the courses data is now successfully passed to the coordinator. However, the view still doesn't update itself despite a change in courses correctly triggering updateUIView. Any advice is appreciated.