Skip to content

Latest commit

 

History

History
150 lines (103 loc) · 6.7 KB

Apple.Accessibility.md

File metadata and controls

150 lines (103 loc) · 6.7 KB
Raw

Apple - Accessibility

Installation Instructions

1. Install Dependencies

  • Apple.Core

2. Install the Package

See the Quick-Start Guide for general installation instructions.

Usage

Please find an introduction to using Apple's Accessibility Plug-in below. For a comprehensive guide to Accessibility on Apple devices, please see Accessibility Developer Documentation

The plugin supports Unity 2020.3 and above, but should work with older versions of Unity.

Table of Contents

Accessibility Elements

Dynamic Type

UI Accommodations

Accessibility Elements

1. Add AccessibilityNode

To enable Apple's Accessibility system to work with a GameObject, the object requires an AccessibilityNode component.

Optionally configure the AccessibilityNode to be a model view container. (see Advanced Features)

2. Add Accessibility Traits and Labels

Select the traits that best describe the node's behavior.

The most common trait is AccessibilityTrait.Button, which informs assistive technologies users that this is a tappable button. Note that AccessibilityTrait is a bitmask, so it is possible for a node to have multiple traits. Please refer to UIAccessibilityTraits Apple Developer docs for more detailed information on accessibility traits.

Next, assign a Label to AccessibilityNode to add a localized description of this accessibility node. For example, a back button might have "Back" as its Label, while a background music settings slider might have "Background Music" instead. For choosing the best label for assistive technologies, please refer to Writing Great Accessibility Labels Apple WWDC talk.

3. Assigning Accessibility Properties

Accessibility properties can be assigned programmatically:

using Apple.Accessibility;

var node = GetComponent<AccessibilityNode>();
node.AccessibilityLabel = MyHelper.LocalizedString("Back");

In addition, you could assign a callback for accessibility properties that changes frequently:

var healthNode = GetComponent<AccessibilityNode>();
healthNode.accessibilityValueDelegate = () =>
{
    return this.currentHealth.ToString();
};

Note: a delegate will take precedence over other assignment methods.

4. Test with VoiceOver

After building and installing a game to an Apple device, test the Accessibility features using VoiceOver. VoiceOver can be turned on or off under Settings > Accessibility > VoiceOver. (Note that device-navigation changes significantly when VoiceOver is turned on. See Turn on and practice VoiceOver on iPhone Apple Support docs for more information on how to navigate a device with VoiceOver on)

VoiceOver can also be switched on or off with one of the following methods:

  1. Triple-click the side button (on an iPhone with Face ID).
  2. Triple-click the Home button (on an iPhone with a Home button).
  3. Activate Siri and say “Turn on VoiceOver” or “Turn off VoiceOver.”

Now that VoiceOver is on, tapping on buttons and game objects that have AccessibilityNode components should result in the VoiceOver system reading out descriptions, which means assistive technologies users will be able to properly interact with them.

5. Advanced Topics

AccessibilityNode follows a tree structure model that helps encode the accessibility hierarchy. This means that an AccessibilityNode can be added to non-interactive HUD containers like a UIPanel. By setting isModal to true, either programmatically or in the Editor, the UIPanel element indicates whether VoiceOver should ignore the accessibility elements within views that are siblings of the element.

Please refer to Apple Support docs accessibilityViewIsModal

Dynamic Type

1. Check Settings

Dynamic Type is a system-wide feature which allows users to scale font size. Try this out for yourself by going to Settings > Display & Brightness > Text Size. To incorporate a user's text size preferences into a Unity app, use the text size multiplier from the AccessibilitySettings script:

var multiplier = AccessibilitySettings.PreferredContentSizeMultiplier;

Scale text elements using the multiplier:

GetComponent<Text>().textSize = multiplier * 48;

Or read the user's preferred size category in place of the multiplier:

ContentSizeCategory category = AccessibilitySettings.PreferredContentSizeCategory;

2. Listening for Changes

Sometimes an app might need to change its behavior when a user changes their accessibility settings.

For example, to subscribe to a user changing their text size preference and respond accordingly, use:

void Start()
{
    AccessibilitySettings.onPreferredContentSizeChanged.AddListener(OnContentSizeChanged);
}

private void OnContentSizeChanged()
{
    // refresh text sizes
}

UI Accommodations

1. Check Settings

Access to user accessibility settings can be found with the AccessibilitySettings API. For example, to check whether the user has turned on the Reduce Motion setting in Settings > Accessibility > Motion:

var isReduceMotionOn = AccessibilitySettings.IsReduceMotionEnabled;

Check AccessibilitySettings.cs for a complete list of supported Accessibility Settings. Please refer to Accessibility for UIKit Apple Support docs for more details on each setting.

2. Listening for Changes

Sometimes an app might need to change its behavior when a user changes his or her accessibility settings.

For example, if a user changes the "Switch Control" setting, you could subscribe to the event by:

void Start()
{
    AccessibilitySettings.onIsSwitchControlRunningChanged.AddListener(SwitchControlSettingChanged);
}

private void SwitchControlSettingChanged()
{
    ...
}