How to manually load UITableView - ios

Question

I kind of have a weird layout here, it's kind of like this (also see pics):
-UITableViewCell 1
----UIView 2
--------UITableView 3
The controller the the UITableView (1) is like that:
//mainTableView (1) controller
var cellHeights = [CGFloat]()
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell()
let card = CardSource.orangeCards[indexPath.row]
cell.configureCardInCell(card)
cellHeights.insert(card.frame.height + 15, at: indexPath.row)
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return cellHeights[indexPath.row]
}
but the problem is that when the screen first loads, the UIViews overlap because the cells are too small because the smaller table view (the one in the UIView) hasn't loaded yet and it's height isn't defined. Proof of this is that when I scroll to the bottom of the main table view then scroll back up cellForRowAt is called again and the two views don't overlap anymore (see pics). So what I basically want is a way to load the small table view and define it's height before the bigger table view loads (or if you have any other solutions, that'd be welcome too)
I know my question isn't very clear, I'm not really good at explaining stuff, so don't hesitate to ask me questions in the comments.
Many thanks!
When the view first loads
After scrolling down then back up
EDIT:
I found this:
static var pharmacyOrangeCard: CardView {
let view = Bundle.main.loadNibNamed("Pharmacy Orange Card", owner: self, options: nil)?.first as! PharmacyTableCardView
print(view.frame.height)
return view
}
prints the correct height. But then, when I try to access it from the controller above, it gives me a smaller number! In the meanwhile, I applied these constraints:
self.translatesAutoresizingMaskIntoConstraints = false
self.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 35).isActive = true
card.centerXAnchor.constraint(equalTo: cell.centerXAnchor).isActive = true
card.topAnchor.constraint(equalTo: cell.topAnchor).isActive = true
But I don't think that affects height, does it?
EDIT 2:
Okay, so I've changed this constraint:
self.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 35).isActive = true
to this:
card.leadingAnchor.constraint(equalTo: cell.leadingAnchor, constant: 17.5).isActive = true
card.trailingAnchor.constraint(equalTo: cell.trailingAnchor, constant: -17.5).isActive = true
So these constraints seem to play a role because now I have this:
enter image description here
By the way, I don't know if that matters but I'm using XIB files for each of these "cards", and the height isn't constrained, so maybe that plays a role?
SOLVING EDIT:
I solved the problem by doing:
override func viewDidAppear(_ animated: Bool) {
mainTableView.reloadData()
}

Answer 1

Once a cell loaded on the screen, you cannot change height for that cell for better UI-Experience,
and in hierarchy heightForRowAt get called before cellForRowAt.
So you had 2 options to choose for a solution to your problem
first:: get your heights values ready before your table view try to loads cells in it (get heights array ready before setting delegate and datasource values to your tableView)
second:: whenever you need to update your tableView cells to re-established with respect to new height values, call this each time after you have updated your height values
yourTableView.reloadData()