Day 32

Adjustable trait for custom value controls

19 Jun 2022

If you are developing a custom component, that can change value, chances are that it will need the adjustable accessibility trait (VoiceOver will say: "Adjustable"). Think of a component that lets you rate from one to five thumbs up (or stars).

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With VoiceOver, you can swipe up/down to increase/decrease the value of adjustable components. You need to implement accessibilityIncrement() and accessibilityDecrement() accordingly, and configure an accessibility value that makes sense. Example code in the image: ```swift override func accessibilityIncrement() { guard value < 5 else { return } value += 1 accessibilityValue = "\(value) of 5" sendActions(for: .valueChanged) } override func accessibilityDecrement() { guard value > 1 else { return } value -= 1 accessibilityValue = "\(value) of 5" sendActions(for: .valueChanged) } ``` Links to the official documentation: * accessibilityincrement() * accessibilitydecrement()

By its name, I misunderstood what shouldGroupAccessibilityChildren does the first time I saw it. It can be used for VoiceOver to traverse all items in a view before moving to the next one, instead of grouping as in combining those elements. VoiceOver traverses elements in the natural reading order, from left to right, top to bottom, in left-to-right languages. Sometimes data is displayed in columns, so that order might not be the most logical one. https://developer.apple.com/documentation/objectivec/nsobject-swift.class/shouldgroupaccessibilitychildren

If an image does not convey additional information, maybe it's just used to make the UI look more attractive, it makes sense for VoiceOver to skip it. UIKit: set isAccessibilityElement to false. SwiftUI: create a decorative image explicitly.


Content © Daniel Devesa Derksen-Staats on Accessibility up to 11! is licensed under CC BY 4.0. License details