Swift version: 5.0
There's a special kind of
flexibleSpace, and this acts like a spring between other buttons, pushing them to one side. A flexible space will always expand to take up as much room as possible, splitting space evenly between other flexible spaces if they exist.
For example, if you add this button to a toolbar, it will sit on the left edge of the toolbar:
let refresh = UIBarButtonItem(barButtonSystemItem: .refresh, target: self, action: #selector(refreshTapped))
If you create and add a flexible space first, then that button will be pushed to the right edge as the flexible space expands to take up most of the toolbar. Here's how you create the flexible space:
let spacer = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
Available from iOS 2.0 – see Hacking with Swift tutorial 4
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.