What is a selector?
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?
Available from iOS 7.0
Did this solution work for you? Please pass it on!
Other people are reading…
- What are convenience initializers?
- How to use @available to deprecate old APIs
- What is a tuple?
- How to check for valid method input using the guard keyword
- How to add a custom initializer to a struct without losing its memberwise initializer
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Help support Hacking with Swift
This site is funded by Hacking with Swift supporters who buy my e-books. If you can, please support my work – it comes packed with bonus material!
