NEW: Got a question? Get help on our new forums! >>

How to identify your Auto Layout constraints

Swift version: 5.1

Paul Hudson    @twostraws   

Auto Layout constraints a powerful way of expressing your layouts, but when they go wrong they can be hard to debug. Fortunately, all constraints have a built-in identifier property that you can use to identify them uniquely.

It’s an optional string so you don’t have to provide anything, but if you do set an identifier you’ll find it much easier to see where your constraints are going wrong because Xcode will use those identifiers in its debug logs.

If you create your constraints in code, just set the identifier property to a string as you go – “Main Title Horizontal Center” for example. If you use Interface Builder, you can select any constraint and you’ll see a dedicated “Identifier” text property you can fill in.

There is literally no reason not to add identifiers to your constraints – they don’t affect your layouts at all, but they do make layout debugging significantly easier!

Hacking with Swift is sponsored by Instabug

SPONSORED Catch bugs as soon as they happen and know exactly why a crash occurred by integrating Instabug's SDK in one minute. You will automatically receive device data, network logs, and reproduction steps with every bug and crash report.

Learn more and get started for free

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

Snapthread is a casual video editor and slideshow maker that makes discovering, compiling and sharing your favorite memories effortless.

Available from iOS 7.0

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 Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) 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 Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 3.5/5