BLACK FRIDAY SALE: Save 50% on all my Swift books and bundles! >>

How to create Quick Look debug previews for your custom types

Swift version: 5.6

Paul Hudson    @twostraws   

Xcode’s Quick Look debugging allows us to visually preview the value of our types, and is capable of showing numbers, strings, attributed strings, colors, images, PDFs, Bezier paths, and more.

By default your custom types don’t have a Quick Look preview, so you won’t see anything useful. But if you add the debugQuickLookObject() method to your type then you can return something you want from there to have it show up in Xcode:

class User {
    var name = "Duane Dibbley"
    var age = 28

    @objc func debugQuickLookObject() -> Any? {
        return "My name is \(name) and I'm \(age)."
    }
}

That will show a string inside Xcode, but you could also format the string with attributes, create an image of your game board, and so on.

Hacking with Swift is sponsored by Guardsquare

SPONSORED AppSweep by Guardsquare helps developers automate the mobile app security testing process with fast, free scans. By using AppSweep’s actionable recommendations, developers can improve the security posture of their apps in accordance with security standards like OWASP.

Learn more

Sponsor Hacking with Swift and reach the world's largest Swift community!

Available from iOS 8.0

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: 4.5/5

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.