Description

As an app developer, I currently am unable to specify an expected focus/tab order for elements in my Xamarin.Forms app that will be used by a screen reader and/or keyboard navigation to improve the usability and accessibility of the app. When this spec is complete, I can explicitly set the TabIndex on any focusable element to have it read to the app user and/or prepare it for input in a particular order.

Acceptance criteria

• Solution must enable app developer to set an integer value on Element.TabIndex with the expectation that focus will cycle through each element in ascending order.
• Conflicts on TabIndex will be resolved by the declaration order.
• If no value is set in TabIndex, the default behavior will be used.
• If the app developer attempts to set a focus order using a custom renderer, the values set by the custom renderer should take precedence.

Per the UWP specification:

• UI elements with TabIndex equal to 0 are added to the tab order based on declaration order in XAML or child collections.
• UI elements with TabIndex greater than 0 are added to the tab order based on the TabIndex value.
• UI elements with TabIndex less than 0 are added to the tab order and appear before any zero value.

API changes

Add: int Element.TabIndex { get; set; }

Description of changes

• UWP: https://docs.microsoft.com/en-us/windows/uwp/accessibility/keyboard-accessibility
• iOS: https://developer.apple.com/documentation/objectivec/nsobject/1615147-accessibilityelements#declarations
• Android: https://developer.android.com/training/keyboard-input/navigation.html#Tab
• macOS: [macOS] Set tab order (e.g. for entries) on a Page #1060 (convert from platform specific)