How do I show/hide a UIBarButtonItem?

Question

I created a toolbar in IB with several buttons. I would like to be able to hide/show one of the buttons depending on the state of the data in the main window.

Answer 1

This is long way down the answer list, but just in case somebody wants an easy copy and paste for the swift solution, here it is

func hideToolbarItem(button: UIBarButtonItem, withToolbar toolbar: UIToolbar) {
    var toolbarButtons: [UIBarButtonItem] = toolbar.items!
    toolbarButtons.removeAtIndex(toolbarButtons.indexOf(button)!)
    toolbar.setItems(toolbarButtons, animated: true)
}

func showToolbarItem(button: UIBarButtonItem, inToolbar toolbar: UIToolbar, atIndex index: Int) {
    var toolbarButtons: [UIBarButtonItem] = toolbar.items!
    if !toolbarButtons.contains(button) {
        toolbarButtons.insert(button, atIndex: index)
        toolbar.setItems(toolbarButtons, animated:true);
    }
}