NEW: My new book Pro SwiftUI is out now – level up your SwiftUI skills today! >>

What is the first responder?

Swift version: 5.6

Paul Hudson    @twostraws   

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.

Hacking with Swift is sponsored by Play

SPONSORED Play is the first native iOS design tool created for designers and engineers. You can install Play for iOS and iPad today and sign up to check out the Beta of our macOS app with SwiftUI code export. We're also hiring engineers!

Click to learn more about Play!

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…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

BUY OUR BOOKS
Buy Pro Swift Buy Pro SwiftUI Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let us know!

Average rating: 3.8/5

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.