UIScrollView sometimes lose its scroll when changing the height of UITableView inside - ios

Question

I have simple UIScrollView with two subviews: UIView and UITableView set in vertical mode. Both of them have their own height constraint:
I set it like this:
tableViewHeightConstraint.constant = CGFloat(height) //height is calculated based on number of cells multiplied 130
calendarViewHeightConstraint.constant = UIApplication.shared.keyWindow!.rootViewController!.traitCollection.isIpad ? 630 : 470
But sometimes when I scroll to the bottom, and then add a new cell to the table view and recalculate height it seems that scroll of scroll view is locked, and I can bouncing but the scroll disappear and I can only bouncing, although I know that I can scroll to the content above or below the current view on the screen. What may be the reason?
I really have to do this like this. There is no possibility to put my view inside table view header view.
This is where I recalculate height:
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.endUpdates()
updateView()
updateTableViewHeight()
}
private func updateTableViewHeight() {
var height = goalFetchedResultsController.fetchedObjects!.count * 130
height += 45
if MyType.selected.hasMonthReport {
height += 130
}
if MyType.selected.hasAnnualReport {
height += 70
height += 130
}
tableViewHeightConstraint.constant = CGFloat(height)
}
New cell is added inside delegate of NSFetchedResultsController.

Answer 1

I'm thinking you need to change your calculation way of height of TableView like,
var height = tablView.contentSize.heigh // You can do + or - here
// your other stuff of calculation.
tableViewHeightConstraint.constant = CGFloat(height)
self.view.layoutIfNeeded() // You need to call after change constraint.