diff options
Diffstat (limited to 'Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs b/Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs new file mode 100644 index 00000000..6d34c6b5 --- /dev/null +++ b/Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs @@ -0,0 +1,214 @@ +using System; +using System.ComponentModel; +using Android.Widget; + +namespace Xamarin.Forms.Platform.Android.FastRenderers +{ + internal class AutomationPropertiesProvider : IDisposable + { + const string GetFromElement = "GetValueFromElement"; + string _defaultContentDescription; + bool? _defaultFocusable; + string _defaultHint; + bool _disposed; + + IVisualElementRenderer _renderer; + + public AutomationPropertiesProvider(IVisualElementRenderer renderer) + { + _renderer = renderer; + _renderer.ElementPropertyChanged += OnElementPropertyChanged; + _renderer.ElementChanged += OnElementChanged; + } + + global::Android.Views.View Control => _renderer?.View; + + VisualElement Element => _renderer?.Element; + + public void Dispose() + { + Dispose(true); + GC.SuppressFinalize(this); + } + + protected virtual void Dispose(bool disposing) + { + if (_disposed) + { + return; + } + + _disposed = true; + + if (_renderer != null) + { + _renderer.ElementChanged -= OnElementChanged; + _renderer.ElementPropertyChanged -= OnElementPropertyChanged; + + _renderer = null; + } + } + + void SetAutomationId(string id = GetFromElement) + { + if (Element == null || Control == null) + { + return; + } + + string value = id; + if (value == GetFromElement) + { + value = Element.AutomationId; + } + + if (!string.IsNullOrEmpty(value)) + { + Control.ContentDescription = value; + } + } + + void SetContentDescription(string contentDescription = GetFromElement) + { + if (Element == null || Control == null) + { + return; + } + + if (SetHint()) + { + return; + } + + if (_defaultContentDescription == null) + { + _defaultContentDescription = Control.ContentDescription; + } + + string value = contentDescription; + if (value == GetFromElement) + { + value = string.Join(" ", (string)Element.GetValue(AutomationProperties.NameProperty), + (string)Element.GetValue(AutomationProperties.HelpTextProperty)); + } + + if (!string.IsNullOrWhiteSpace(value)) + { + Control.ContentDescription = value; + } + else + { + Control.ContentDescription = _defaultContentDescription; + } + } + + void SetFocusable(bool? value = null) + { + if (Element == null || Control == null) + { + return; + } + + if (!_defaultFocusable.HasValue) + { + _defaultFocusable = Control.Focusable; + } + + Control.Focusable = + (bool)(value ?? (bool?)Element.GetValue(AutomationProperties.IsInAccessibleTreeProperty) ?? _defaultFocusable); + } + + bool SetHint(string hint = GetFromElement) + { + if (Element == null || Control == null) + { + return false; + } + + var textView = Control as TextView; + if (textView == null) + { + return false; + } + + // Let the specified Title/Placeholder take precedence, but don't set the ContentDescription (won't work anyway) + if (((Element as Picker)?.Title ?? (Element as Entry)?.Placeholder) != null) + { + return true; + } + + if (_defaultHint == null) + { + _defaultHint = textView.Hint; + } + + string value = hint; + if (value == GetFromElement) + { + value = string.Join(". ", (string)Element.GetValue(AutomationProperties.NameProperty), + (string)Element.GetValue(AutomationProperties.HelpTextProperty)); + } + + textView.Hint = !string.IsNullOrWhiteSpace(value) ? value : _defaultHint; + + return true; + } + + void SetLabeledBy() + { + if (Element == null || Control == null) + return; + + var elemValue = (VisualElement)Element.GetValue(AutomationProperties.LabeledByProperty); + + if (elemValue != null) + { + var id = Control.Id; + if (id == -1) + id = Control.Id = FormsAppCompatActivity.GetUniqueId(); + + var renderer = elemValue?.GetRenderer(); + renderer?.SetLabelFor(id); + } + } + + void OnElementChanged(object sender, VisualElementChangedEventArgs e) + { + if (e.OldElement != null) + { + e.OldElement.PropertyChanged -= OnElementPropertyChanged; + } + + if (e.NewElement != null) + { + e.NewElement.PropertyChanged += OnElementPropertyChanged; + } + + SetHint(); + SetAutomationId(); + SetContentDescription(); + SetFocusable(); + SetLabeledBy(); + } + + void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e) + { + if (e.PropertyName == AutomationProperties.HelpTextProperty.PropertyName) + { + SetContentDescription(); + } + else if (e.PropertyName == AutomationProperties.NameProperty.PropertyName) + { + SetContentDescription(); + } + else if (e.PropertyName == AutomationProperties.IsInAccessibleTreeProperty.PropertyName) + { + SetFocusable(); + } + else if (e.PropertyName == AutomationProperties.LabeledByProperty.PropertyName) + { + SetLabeledBy(); + } + } + } +}
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