Animating inserting a new row into a new section in a UITableView - ios

Question

The problem is quite simple.
I am attempting to animate the addition of a new row into a new section.
The update code:
func updateTableView(sessions: [Sessions]) {
self.foundSessions = sessions
if self.numberOfSections(in: self.tableView) == 0 {
self.tableView.beginUpdates()
self.tableView.insertSections([0], with: .automatic)
self.tableView.endUpdates()
}
for i in 0..<self.foundSessions.count {
self.tableView.beginUpdates()
self.tableView.insertRows(at: [IndexPath(row: i, section: 0)], with: .automatic
self.tableView.endUpdates()
}
}
UITableViewDataSource code:
override func numberOfSections(in tableView: UITableView) -> Int {
if foundSessions.isEmpty { return 0 }
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return foundSessions.count
}
And the error:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'attempt to insert section 0 but there are only 0 sections after the update
Obviously, it seems the section is not getting inserted. If I take out insertRows, the empty section eventually shows up, as can be seen by the tableFooterView at the top. I have followed the advice of the posts here, here, here, and here, and have read the respective Apple Documentation on the manner, obviously to no avail.
Any iOS gurus out there able to show me the error in my ways?
EDIT: More debugging info - updateTableView is called in the callback of an async function. I wrapped all this code in a DispatchQueue.main.async block in an attempt to remedy the situation, however, was unsuccessful.

Answer 1

Try putting all your updates to section and it's row in one block, begin ... end like below
self.tableView.beginUpdates()
self.tableView.insertSections([0], with: .automatic)
for i in 0..<self.foundSessions.count {
self.tableView.insertRows(at: [IndexPath(row: i, section: 0)], with: .automatic
}
self.tableView.endUpdates()