maui-linux/Xamarin.Forms.Platform.GTK/VisualElementRenderer.cs

328 строки
8.0 KiB
C#
Исходник Обычный вид История

2017-09-28 14:52:27 +03:00
using Gtk;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using Xamarin.Forms.Platform.GTK.Extensions;
using Container = Xamarin.Forms.Platform.GTK.GtkFormsContainer;
2017-09-28 14:52:27 +03:00
using Control = Gtk.Widget;
namespace Xamarin.Forms.Platform.GTK
{
public class VisualElementRenderer<TElement, TNativeElement> : Container, IVisualElementRenderer, IDisposable, IEffectControlProvider
where TElement : VisualElement
where TNativeElement : Control
{
private bool _disposed;
private readonly PropertyChangedEventHandler _propertyChangedHandler;
private readonly List<EventHandler<VisualElementChangedEventArgs>> _elementChangedHandlers = new List<EventHandler<VisualElementChangedEventArgs>>();
private VisualElementTracker<TElement, TNativeElement> _tracker;
private string _defaultAccessibilityLabel;
private string _defaultAccessibilityHint;
protected VisualElementRenderer()
{
_propertyChangedHandler = OnElementPropertyChanged;
}
protected VisualElementTracker<TElement, TNativeElement> Tracker
{
get { return _tracker; }
set
{
if (_tracker == value)
return;
if (_tracker != null)
{
_tracker.Dispose();
_tracker.Updated -= OnTrackerUpdated;
}
_tracker = value;
if (_tracker != null)
{
_tracker.Updated += OnTrackerUpdated;
UpdateTracker();
}
}
}
public TNativeElement Control { get; set; }
public TElement Element { get; set; }
public Container Container => this;
public bool Disposed { get { return _disposed; } }
VisualElement IVisualElementRenderer.Element
{
get
{
return Element;
}
}
protected IElementController ElementController => Element as IElementController;
protected virtual bool PreventGestureBubbling { get; set; } = false;
event EventHandler<VisualElementChangedEventArgs> IVisualElementRenderer.ElementChanged
{
add { _elementChangedHandlers.Add(value); }
remove { _elementChangedHandlers.Remove(value); }
}
public event EventHandler<ElementChangedEventArgs<TElement>> ElementChanged;
void IEffectControlProvider.RegisterEffect(Effect effect)
{
var platformEffect = effect as PlatformEffect;
if (platformEffect != null)
OnRegisterEffect(platformEffect);
}
void IVisualElementRenderer.SetElement(VisualElement element)
{
SetElement((TElement)element);
}
public void SetElement(TElement element)
{
var oldElement = Element;
Element = element;
if (oldElement != null)
{
oldElement.FocusChangeRequested -= OnElementFocusChangeRequested;
oldElement.PropertyChanged -= _propertyChangedHandler;
}
if (element != null)
{
element.PropertyChanged += _propertyChangedHandler;
element.FocusChangeRequested += OnElementFocusChangeRequested;
if (Tracker == null)
{
Tracker = new VisualElementTracker<TElement, TNativeElement>();
}
}
OnElementChanged(new ElementChangedEventArgs<TElement>(oldElement, element));
SetAccessibilityLabel();
SetAccessibilityHint();
}
public void SetElementSize(Size size)
{
Layout.LayoutChildIntoBoundingRegion(Element,
new Rectangle(Element.X, Element.Y, size.Width, size.Height));
}
public virtual SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
{
if (Children.Length == 0)
return new SizeRequest();
return Control.GetDesiredSize(widthConstraint, heightConstraint);
}
protected override void OnShown()
{
base.OnShown();
UpdateIsVisible();
}
public override void Destroy()
{
base.Destroy();
Dispose(true);
}
protected override void OnSizeAllocated(Gdk.Rectangle allocation)
{
base.OnSizeAllocated(allocation);
double width, height, translationX, translationY;
Rectangle bounds = Element.Bounds;
translationX = Element.TranslationX;
translationY = Element.TranslationY;
width = bounds.Width >= -1 ? bounds.Width : 0;
height = bounds.Height >= -1 ? bounds.Height : 0;
Container.SetSize(width, height);
Container.MoveTo((int)bounds.X + translationX, (int)bounds.Y + translationY);
for (var i = 0; i < ElementController.LogicalChildren.Count; i++)
{
var child = ElementController.LogicalChildren[i] as VisualElement;
if (child != null)
{
var renderer = Platform.GetRenderer(child);
if (renderer != null)
{
width = child.Bounds.Width >= -1 ? child.Bounds.Width : 0;
height = child.Bounds.Height >= -1 ? child.Bounds.Height : 0;
translationX = child.TranslationX;
translationY = child.TranslationY;
renderer.Container.SetSize(width, height);
renderer.Container.MoveTo(child.Bounds.X + translationX, child.Bounds.Y + translationY);
}
}
}
}
protected virtual void OnRegisterEffect(PlatformEffect effect)
{
effect.SetContainer(this);
effect.SetControl(Container);
}
protected virtual void OnElementChanged(ElementChangedEventArgs<TElement> e)
{
var args = new VisualElementChangedEventArgs(e.OldElement, e.NewElement);
for (var i = 0; i < _elementChangedHandlers.Count; i++)
_elementChangedHandlers[i](this, args);
ElementChanged?.Invoke(this, e);
}
protected virtual void SetNativeControl(TNativeElement view)
{
Control = view;
UpdateBackgroundColor();
UpdateIsVisible();
UpdateSensitive();
}
protected virtual void Dispose(bool disposing)
{
if (!disposing || _disposed)
return;
_disposed = true;
Tracker?.Dispose();
Tracker = null;
}
protected virtual void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == VisualElement.IsVisibleProperty.PropertyName)
UpdateIsVisible();
else if (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName)
UpdateBackgroundColor();
else if (e.PropertyName == VisualElement.IsEnabledProperty.PropertyName)
UpdateSensitive();
else if (e.PropertyName == AutomationProperties.HelpTextProperty.PropertyName)
SetAccessibilityHint();
else if (e.PropertyName == AutomationProperties.NameProperty.PropertyName)
SetAccessibilityLabel();
}
protected virtual void UpdateBackgroundColor()
{
if (_disposed || Element == null || Control == null)
return;
Container.SetBackgroundColor(Element.BackgroundColor);
}
protected virtual void SetAccessibilityHint()
{
if (_disposed || Element == null || Control == null)
return;
if (_defaultAccessibilityHint == null)
_defaultAccessibilityHint = Accessible.Name;
var helpText = (string)Element.GetValue(AutomationProperties.HelpTextProperty) ?? _defaultAccessibilityHint;
if (!string.IsNullOrEmpty(helpText))
{
Accessible.Name = helpText;
}
}
protected virtual void SetAccessibilityLabel()
{
if (_disposed || Element == null || Control == null)
return;
if (_defaultAccessibilityLabel == null)
_defaultAccessibilityLabel = Accessible.Description;
var name = (string)Element.GetValue(AutomationProperties.NameProperty) ?? _defaultAccessibilityLabel;
if (!string.IsNullOrEmpty(name))
{
Accessible.Description = name;
}
}
protected virtual void UpdateNativeControl()
{
UpdateSensitive();
}
internal virtual void OnElementFocusChangeRequested(object sender, VisualElement.FocusRequestArgs args)
{
var control = Control as Control;
if (control == null)
return;
if (args.Focus)
args.Result = control.IsFocus = true;
else
{
control.IsFocus = false;
args.Result = true;
}
}
private void UpdateIsVisible()
{
if (_disposed || Element == null || Control == null)
return;
Container.Visible = Element.IsVisible;
}
private void UpdateSensitive()
{
if (_disposed || Element == null || Control == null)
return;
Control.Sensitive = Element.IsEnabled;
}
private void OnTrackerUpdated(object sender, EventArgs e)
{
UpdateNativeControl();
}
private void UpdateTracker()
{
if (_tracker == null)
return;
_tracker.PreventGestureBubbling = PreventGestureBubbling;
_tracker.Control = Control;
_tracker.Element = Element;
_tracker.Container = Container;
}
}
}