Why does my UITableView “jump” when inserting or removing a row?

Question

(Happy to accept an answer in Swift or Objective-C)

My table view has a few sections, and when a button is pressed, I want to insert a row at the end of section 0.

Answer 1

@GaétanZ's solution did not work for me (IOS12) but he's concept is right..

SO I did the next logical step:

IF table content does not know how tall is the cell THEN lets just “keep on scrolling" down RIGHT AFTER inserting the cell

private func insertBottomBubble(withCompletionHandler completion: (() -> Void)?) {
    let bottomIndexPath = IndexPath(row: cbModelViewController!.viewModelsCount - 1, section: 0)


    CATransaction.begin()
    CATransaction.setAnimationDuration(0.9)
    CATransaction.setCompletionBlock {
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
            self.scrollToBottom(withCompletionHandler: completion)
        }
    }
    tableView.insertRows(at: [bottomIndexPath], with: isLeft == true ? .left : .right)
    self.scrollToBottom(withCompletionHandler: nil) // no jump, keep it down :D
    CATransaction.commit()
}


func scrollToBottom(withCompletionHandler completion: (() -> Void)?) {
    let bottomMessageIndexPath = IndexPath(row: tableView.numberOfRows(inSection: 0) - 1, section: 0)
    UIView.animate(withDuration: 0.45,
                   delay: TimeInterval(0),
                   options: UIView.AnimationOptions.curveEaseInOut,
                   animations: {
                    self.tableView.scrollToRow(at: bottomMessageIndexPath, at: .bottom, animated: false)
    },
                   completion: { success in
                    if success {
                        completion?()
                    }

    })

iOS 12 tested only