Swift version: 5.4
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?
SAVE 50% This Black Friday all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.
Available from iOS 7.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Link copied to your pasteboard.