diff options
Diffstat (limited to 'Xamarin.Forms.Platform.MacOS/Renderers/ScrollViewRenderer.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.MacOS/Renderers/ScrollViewRenderer.cs | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.MacOS/Renderers/ScrollViewRenderer.cs b/Xamarin.Forms.Platform.MacOS/Renderers/ScrollViewRenderer.cs new file mode 100644 index 00000000..c41d1d2b --- /dev/null +++ b/Xamarin.Forms.Platform.MacOS/Renderers/ScrollViewRenderer.cs @@ -0,0 +1,214 @@ +using System; +using System.ComponentModel; +using AppKit; +using RectangleF = CoreGraphics.CGRect; +using ObjCRuntime; +using Foundation; + +// ReSharper disable UnusedMember.Local +// ReSharper disable UnusedParameter.Local + +namespace Xamarin.Forms.Platform.MacOS +{ + public class ScrollViewRenderer : NSScrollView, IVisualElementRenderer + { + EventTracker _events; + VisualElementTracker _tracker; + ScrollToRequestedEventArgs _requestedScroll; + IVisualElementRenderer _contentRenderer; + + public ScrollViewRenderer() : base(RectangleF.Empty) + { + DrawsBackground = false; + ContentView.PostsBoundsChangedNotifications = true; + NSNotificationCenter.DefaultCenter.AddObserver(this, new Selector(nameof(UpdateScrollPosition)), + BoundsChangedNotification, ContentView); + } + + IScrollViewController Controller => Element as IScrollViewController; + + public VisualElement Element { get; private set; } + + public event EventHandler<VisualElementChangedEventArgs> ElementChanged; + + public SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint) + { + return NativeView.GetSizeRequest(widthConstraint, heightConstraint, 44, 44); + } + + public NSView NativeView => this; + + public void SetElement(VisualElement element) + { + _requestedScroll = null; + var oldElement = Element; + Element = element; + + if (oldElement != null) + { + oldElement.PropertyChanged -= HandlePropertyChanged; + ((IScrollViewController)oldElement).ScrollToRequested -= OnScrollToRequested; + } + + if (element != null) + { + element.PropertyChanged += HandlePropertyChanged; + ((IScrollViewController)element).ScrollToRequested += OnScrollToRequested; + if (_tracker == null) + { + PackContent(); + + _events = new EventTracker(this); + _events.LoadEvents(this); + + _tracker = new VisualElementTracker(this); + _tracker.NativeControlUpdated += OnNativeControlUpdated; + } + + UpdateContentSize(); + UpdateBackgroundColor(); + + OnElementChanged(new VisualElementChangedEventArgs(oldElement, element)); + } + } + + public void SetElementSize(Size size) + { + Xamarin.Forms.Layout.LayoutChildIntoBoundingRegion(Element, + new Rectangle(Element.X, Element.Y, size.Width, size.Height)); + } + + public NSViewController ViewController => null; + + public override void Layout() + { + base.Layout(); + LayoutSubviews(); + } + + protected override void Dispose(bool disposing) + { + if (disposing) + { + if (_tracker == null) + return; + + SetElement(null); + + _tracker.NativeControlUpdated -= OnNativeControlUpdated; + _tracker.Dispose(); + _tracker = null; + + _events.Dispose(); + _events = null; + + ClearContentRenderer(); + + //NSNotificationCenter.DefaultCenter.RemoveObserver(this, BoundsChangedNotification); + } + + base.Dispose(disposing); + } + + void OnElementChanged(VisualElementChangedEventArgs e) + { + ElementChanged?.Invoke(this, e); + } + + void PackContent() + { + ClearContentRenderer(); + + if (Controller.Children.Count == 0 || !(Controller.Children[0] is VisualElement)) + return; + + var content = (VisualElement)Controller.Children[0]; + if (Platform.GetRenderer(content) == null) + Platform.SetRenderer(content, Platform.CreateRenderer(content)); + + _contentRenderer = Platform.GetRenderer(content); + + DocumentView = _contentRenderer.NativeView; + } + + void LayoutSubviews() + { + if (_requestedScroll != null && Superview != null) + { + var request = _requestedScroll; + _requestedScroll = null; + OnScrollToRequested(this, request); + } + } + + void HandlePropertyChanged(object sender, PropertyChangedEventArgs e) + { + if (e.PropertyName == ScrollView.ContentSizeProperty.PropertyName) + UpdateContentSize(); + else if (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName) + UpdateBackgroundColor(); + } + + void HandleScrollAnimationEnded(object sender, EventArgs e) + { + Controller.SendScrollFinished(); + } + + void HandleScrolled(object sender, EventArgs e) + { + UpdateScrollPosition(); + } + + void OnNativeControlUpdated(object sender, EventArgs eventArgs) + { + UpdateContentSize(); + } + + void OnScrollToRequested(object sender, ScrollToRequestedEventArgs e) + { + if (Superview == null) + { + _requestedScroll = e; + return; + } + + Point scrollPoint = (e.Mode == ScrollToMode.Position) + ? new Point(e.ScrollX, Element.Height - e.ScrollY) + : Controller.GetScrollPositionForElement(e.Element as VisualElement, e.Position); + + (DocumentView as NSView)?.ScrollPoint(scrollPoint.ToPointF()); + + Controller.SendScrollFinished(); + } + + void UpdateBackgroundColor() + { + BackgroundColor = Element.BackgroundColor.ToNSColor(Color.Transparent); + } + + void UpdateContentSize() + { + if (_contentRenderer == null) + return; + var contentSize = ((ScrollView)Element).ContentSize.ToSizeF(); + if (!contentSize.IsEmpty) + _contentRenderer.NativeView.Frame = new RectangleF(0, Element.Height - contentSize.Height, contentSize.Width, + contentSize.Height); + } + + [Export(nameof(UpdateScrollPosition))] + void UpdateScrollPosition() + { + var convertedPoint = (DocumentView as NSView)?.ConvertPointFromView(ContentView.Bounds.Location, ContentView); + if (convertedPoint.HasValue) + Controller.SetScrolledPosition(Math.Max(0, convertedPoint.Value.X), Math.Max(0, convertedPoint.Value.Y)); + } + + void ClearContentRenderer() + { + _contentRenderer?.NativeView?.RemoveFromSuperview(); + _contentRenderer?.Dispose(); + _contentRenderer = null; + } + } +}
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