private static bool DoesHideDescendants(UIElement element)
{
ImportantForAccessibility importantForAccessibility = GetImportantForAccessibilityAttached(element);
bool isAccessibilityLabelSet = GetAccessibilityLabelAttached(element) != null;
return(importantForAccessibility == ImportantForAccessibility.Yes ||
importantForAccessibility == ImportantForAccessibility.NoHideDescendants ||
(importantForAccessibility == ImportantForAccessibility.Auto && isAccessibilityLabelSet == true));
}
/// <summary>
/// Sets the ImportantForAccessibility property for <paramref name="uiElement"/>.
/// It uses AutomationProperties.AccessibilityView to expose the element and its children
/// to narrator. ImportantForAccessibility value is stored as an attached property.
/// </summary>
/// <param name="uiElement">Element which ImportantForAccessibility property is set.</param>
/// <param name="importantForAccessibility">The new value of ImportantForAccessibility property.</param>
public static void SetImportantForAccessibility(UIElement uiElement, ImportantForAccessibility importantForAccessibility)
{
// Check if property is already set to requested value.
if (GetImportantForAccessibilityAttached(uiElement) == importantForAccessibility)
{
return;
}
SetImportantForAccessibilityAttached(uiElement, importantForAccessibility);
UpdateName(uiElement);
UpdateAccessibilityViewIfNeeded(uiElement);
}
/// <summary>
/// Sets the ImportantForAccessibility property for <paramref name="uiElement"/>.
/// It uses AutomationProperties.AccessibilityView to expose the element and its children
/// to narrator. ImportantForAccessibility value is stored as an attached-like property.
/// </summary>
/// <param name="uiElement">Element which ImportantForAccessibility property is set.</param>
/// <param name="importantForAccessibility">The new value of ImportantForAccessibility property.</param>
public static void SetImportantForAccessibility(UIElement uiElement, ImportantForAccessibility importantForAccessibility)
{
// Check if property is already set to requested value.
if (GetImportantForAccessibilityProp(uiElement) == importantForAccessibility)
{
return;
}
SetImportantForAccessibilityProp(uiElement, importantForAccessibility);
// Mark element as dirty
MarkElementDirty(uiElement);
}
void UpdateAccessibilityImportance(Page page, ImportantForAccessibility importantForAccessibility, bool forceFocus)
{
var pageRenderer = Android.Platform.GetRenderer(page);
if (pageRenderer?.View == null)
{
return;
}
pageRenderer.View.ImportantForAccessibility = importantForAccessibility;
if (forceFocus)
{
pageRenderer.View.SendAccessibilityEvent(global::Android.Views.Accessibility.EventTypes.ViewFocused);
}
}
void UpdateAccessibilityImportance(Page page, ImportantForAccessibility importantForAccessibility, bool forceFocus)
{
var pageRenderer = page.Handler as INativeViewHandler;
if (pageRenderer?.NativeView == null)
{
return;
}
pageRenderer.NativeView.ImportantForAccessibility = importantForAccessibility;
if (forceFocus)
{
pageRenderer.NativeView.SendAccessibilityEvent(global::Android.Views.Accessibility.EventTypes.ViewFocused);
}
}
/// <summary>
/// Sets AccessibilityView property for <paramref name="element"/> and its children according to
/// the element's <paramref name="importantForAccessibility"/> property and
/// <see cref="AccessibilityLabelAttachedProperty"/> values.
/// </summary>
/// <param name="element"></param>
/// <param name="elementPeer"></param>
/// <param name="importantForAccessibility"></param>
private static void UpdateAccessibilityViewForUIElement(UIElement element, AutomationPeer elementPeer, ImportantForAccessibility importantForAccessibility)
{
switch (importantForAccessibility)
{
case ImportantForAccessibility.Auto when GetAccessibilityLabelAttached(element) == null:
element.ClearValue(AutomationProperties.AccessibilityViewProperty);
SetChildrenAccessibilityViewFromImportantForAccessibility(elementPeer);
break;
case ImportantForAccessibility.Auto when GetAccessibilityLabelAttached(element) != null:
case ImportantForAccessibility.Yes:
var currentAccessibilityView = AutomationProperties.GetAccessibilityView(element);
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Content);
// Generate the label in case the element was hidden.
if (currentAccessibilityView == AccessibilityView.Raw)
{
UpdateName(element);
}
SetChildrenAccessibilityView(elementPeer, AccessibilityView.Raw);
break;
case ImportantForAccessibility.No:
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Raw);
SetChildrenAccessibilityViewFromImportantForAccessibility(elementPeer);
break;
case ImportantForAccessibility.NoHideDescendants:
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Raw);
SetChildrenAccessibilityView(elementPeer, AccessibilityView.Raw);
break;
default:
break;
}
}
/// <summary>
/// ImportantForAccessibilityAttached property setter.
/// </summary>
/// <param name="element"></param>
/// <param name="value"></param>
private static void SetImportantForAccessibilityAttached(UIElement element, ImportantForAccessibility value)
{
element.SetValue(ImportantForAccessibilityAttachedProperty, value);
}
/// <summary>
/// Sets AccessibilityView property for <paramref name="element"/> and its children according to
/// the element's <paramref name="importantForAccessibility"/> property and
/// <see cref="AccessibilityLabelAttachedProperty"/> values.
/// </summary>
/// <param name="element"></param>
/// <param name="elementPeer"></param>
/// <param name="importantForAccessibility"></param>
private static void UpdateAccessibilityViewForUIElement(UIElement element, AutomationPeer elementPeer, ImportantForAccessibility importantForAccessibility)
{
switch (importantForAccessibility)
{
case ImportantForAccessibility.Auto when GetAccessibilityLabelAttached(element) == null:
element.ClearValue(AutomationProperties.AccessibilityViewProperty);
SetChildrenAccessibilityViewFromImportantForAccessibility(elementPeer);
break;
case ImportantForAccessibility.Auto when GetAccessibilityLabelAttached(element) != null:
case ImportantForAccessibility.Yes:
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Content);
SetChildrenAccessibilityView(elementPeer, AccessibilityView.Raw);
break;
case ImportantForAccessibility.No:
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Raw);
SetChildrenAccessibilityViewFromImportantForAccessibility(elementPeer);
break;
case ImportantForAccessibility.NoHideDescendants:
AutomationProperties.SetAccessibilityView(element, AccessibilityView.Raw);
SetChildrenAccessibilityView(elementPeer, AccessibilityView.Raw);
break;
default:
break;
}
}
private static void SetImportantForAccessibilityProp(UIElement element, ImportantForAccessibility value)
{
EnsureElementAccessibilityContext(element).ImportantForAccessibilityProp = value;
}
