What is a selector?
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 Timer and 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?
SPONSORED From August 2nd to 8th you can join a FREE crash course for mid/senior iOS devs who want to achieve an expert level of technical and practical skills – it’s the fast track to being a complete senior developer!
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 7.0
Similar solutions…
- How to fix “argument of #selector refers to instance method that is not exposed to Objective-C”
- How to cancel a delayed perform() call
- How to use UIKeyCommand to add keyboard shortcuts
- How to add a bar button to a navigation bar
- How to adjust a UIScrollView to fit the keyboard
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
