UITableView reload after navigation controller back not showing value changes - uitableview

Question

I have a table view where I am getting data from Firebase. The table is in a view controller that is part of a navigation controller. When coming to the view from it's parent view, the table data always displays correctly. When I go to the detail view when I click a row and come back, the changes I have made to my data are not showing even though the data values are the new values.
I am loading the table in viewWillAppear so that I can reload the data when coming back from the detail view controller. I am using DispatchQueue.main.async since the UI code is in a completion handler from the Firebase Call. I can set breakpoints and see that the data is being updated from FB and the table is reloading all the rows.
The specific issue I am having is an image, which is hidden by default, should no longer be hidden based on a data value from FB. I can step in the debugger and see that the data says not to hide the image, the image.isHidden = false is called, yet the image doesn't appear. All of my UI calls are wrapped in DispatchQueue.main.async if they are called from a closure. The image will show if I come from the parent view controller to the VC with the tableview, but when going back from the detail VC it doesn't show.
According to the code it should be working when stepping through in the debugger, the data values are correct and the image is being set to hidden/not hidden correctly.
Here is the ViewController Class that has the TableView
override func viewDidLoad() {
super.viewDidLoad()
}
// We want the table to reload every time the page appears
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
RouteService.instance.getRouteByIdFromFirebase(id: route.id) { [weak self] (route) in
guard let self = self else {return}
self.route = route
// Initialize the ViewModel as the table view delegate
self.routeDetailsVM.initialize(route : route,routeDetailsVC : self)
self.segmentsTableView.dataSource = self.routeDetailsVM
self.segmentsTableView.delegate = self.routeDetailsVM
DispatchQueue.main.async { [weak self] in
guard let self = self else { return }
self.segmentsTableView.reloadData()
}
}
}
The UITableViewCell Class
class TravelSegmentTableViewCell: UITableViewCell {
static let cellHeight : CGFloat = 100
static let identifier = "TravelSegmentTableViewCell"
#IBOutlet weak var completedImage: UIImageView!
func initToModel(segment : Segment, routeDetailsVM : RouteDetailsVM) {
setCompletedImageVisible(segment: segment,completedImage : completedImage)
}
func setCompletedImageVisible(segment : Segment,completedImage : UIImageView) {
if (segment.status == .finished) {
// This is getting called correctly but when coming
// back from the details VC it's not showing the image
// When coming from parent VC it works
completedImage.isHidden = false
}
}
UITableViewDelegate Class
// Cell for Row at Index Path Method
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let segment = route.segments[indexPath.row]
let type = segment.type
switch (type) {
case .pickup :
if let cell = tableView.dequeueReusableCell(withIdentifier: PickupSegmentTableViewCell.identifier, for: indexPath) as? PickupSegmentTableViewCell {
cell.initToModel(segment: segment,routeDetailsVM: self)
return cell
} else {
let cell = PickupSegmentTableViewCell()
cell.initToModel(segment: segment, routeDetailsVM: self)
return cell
}
case .delivery :
if let cell = tableView.dequeueReusableCell(withIdentifier: DeliverySegmentTableViewCell.identifier, for: indexPath) as? DeliverySegmentTableViewCell {
cell.initToModel(segment: segment,routeDetailsVM: self)
return cell
} else {
let cell = DeliverySegmentTableViewCell()
cell.initToModel(segment: segment, routeDetailsVM: self)
return cell
}
// This is the cell type in question
case .travel :
if let cell = tableView.dequeueReusableCell(withIdentifier: TravelSegmentTableViewCell.identifier, for: indexPath) as? TravelSegmentTableViewCell {
cell.initToModel(segment: segment, routeDetailsVM: self)
} else {
let cell = TravelSegmentTableViewCell()
cell.initToModel(segment: segment, routeDetailsVM: self)
return cell
}
default :
return UITableViewCell()
}
print("RouteDetailsVM:cellForRowAt indexPath ERROR - Returning blank UITableViewCell for type = \(type)")
return UITableViewCell()
}

Answer 1

The reason for the behavior is if you look inside cell for row at index path and at the .travel switch, I never return the tableViewCell that I dequeued. The code would fall through to the bottom and return a default UITableViewCell instead of the TravelSegmentTableViewCell
Here is what the code should look like
....
case .travel :
if let cell = tableView.dequeueReusableCell(withIdentifier: TravelSegmentTableViewCell.identifier, for: indexPath) as? TravelSegmentTableViewCell {
cell.initToModel(segment: segment, routeDetailsVM: self)
// THIS IS WHAT WAS MISSING
return cell
} else {
let cell = TravelSegmentTableViewCell()
cell.initToModel(segment: segment, routeDetailsVM: self)
return cell
}
default :
return UITableViewCell()
}
return UITableViewCell()
}