Selectors are effectively the names of methods on an object or struct, and they are used to execute some code at runtime. They were common in Objective-C, but the earliest versions of Swift didn't include some core selector functionality so their use declined for a while. That functionality (things like
performSelector(inBackground:)) has since been restored.
In Swift, selectors are most commonly found when working with the target/action paradigm that you find in classes such as
UIBarButtonItem. For example, when you create a timer you need to tell it who to notify when the timer fires (the target) and what selector should be called (the action). The same goes for bar button items: when the button is tapped, what selector should be called, and on what object?
Available from iOS 7.0
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Need to know Objective-C fast?
I wrote a book dedicated to teaching Objective-C to developers who already know Swift – it's the fastest way to get up to speed!