What is the first responder?
Swift version: 5.6
Most of UIKit has a concept of responders baked deep into the system, but it’s not common you need to work with it directly. It’s Apple’s implementation of a design pattern called the Chain of Responsibility: UIKit asks one component if it can respond to an action, but if it can’t it gets passed to another component, and if that can’t respond then it gets passed on and on until something can respond – it’s a chain of responders.
The first responder is whatever control is currently ready to respond to actions. In UIKit this is usually the control that has activated the keyboard and is receiving input. If you want that text control to stop waiting for input – which in turn dismisses the keyboard – you should call its resignFirstResponder() method, which passes the first responder baton to the next waiting component.
The responder chain is how events bubble upwards on Apple platforms: touchesBegan() might be implemented on a view, on its view controller, on a parent view controller, or even higher up, but it will always be triggered somewhere when it happens.
BUILD THE ULTIMATE PORTFOLIO APP Most Swift tutorials help you solve one specific problem, but in my Ultimate Portfolio App series I show you how to get all the best practices into a single app: architecture, testing, performance, accessibility, localization, project organization, and so much more, all while building a SwiftUI app that works on iOS, macOS and watchOS.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 2.0 – learn more in my book Swift Design Patterns
Similar solutions…
- How to find the first matching element in an array
- How to find the index of the first matching array element
- How to remove the first or last item from an array
- What calls the first async function?
- How to capitalize the first letter of a string
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
