SALE: Save 50% on all my books and bundles >>

Working with presentations

Paul Hudson    @twostraws   

Fully updated for Xcode 11.4

SwiftUI’s declarative approach to programming means that we don’t create and present alert and action sheets in the same way as we did in UIKit. Instead, we define the conditions in which they should be shown, tell it what they should look like, then leave it to figure the rest out for itself.

This is all accomplished using modifiers, which attach new UI to our view that will be shown when a condition is satisfied. You can attach as many as you want, and they effectively lie in wait watching until their condition becomes true, at which point they show their UI. For example, you might toggle a Boolean inside a button press, which triggers an alert to show.

You can attach presentations to your main view or any of its children – even to the button that adjusts your state so the presentation triggers. It’s a subtle distinction, but it’s important to understand that these presentations aren’t attached to the button because it’s a button – i.e., that doesn’t in any way make the alert be shown because the button was tapped. Instead, we’re attaching it to our view hierarchy so that SwiftUI is aware that it might be shown at any point.

Hacking with Swift is sponsored by RevenueCat

SPONSORED Building in-app subscriptions are hard. RevenueCat makes it simple. With their open source SDKs, you can painlessly implement subscriptions for your app in hours, not months.

Explore the docs to learn more

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.

Similar solutions…

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: 4.0/5