Initial import

1 files changed, 61 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs
new file mode 100644
index 00000000..933f436f
--- /dev/null
+++ b/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs
@@ -0,0 +1,61 @@
+namespace Xamarin.Forms.Platform.Android
+{
+	public class NativeViewWrapperRenderer : ViewRenderer<NativeViewWrapper, global::Android.Views.View>
+	{
+		public override SizeRequest GetDesiredSize(int widthConstraint, int heightConstraint)
+		{
+			if (Element?.GetDesiredSizeDelegate == null)
+				return base.GetDesiredSize(widthConstraint, heightConstraint);
+
+			// The user has specified a different implementation of GetDesiredSizeDelegate
+			SizeRequest? result = Element.GetDesiredSizeDelegate(this, widthConstraint, heightConstraint);
+
+			// If the delegate returns a SizeRequest, we use it; if it returns null,
+			// fall back to the default implementation
+			return result ?? base.GetDesiredSize(widthConstraint, heightConstraint);
+		}
+
+		protected override void OnElementChanged(ElementChangedEventArgs<NativeViewWrapper> e)
+		{
+			base.OnElementChanged(e);
+
+			if (e.OldElement == null)
+			{
+				SetNativeControl(Element.NativeView);
+				Control.LayoutChange += (sender, args) => Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			}
+		}
+
+		protected override void OnLayout(bool changed, int l, int t, int r, int b)
+		{
+			if (Element?.OnLayoutDelegate == null)
+			{
+				base.OnLayout(changed, l, t, r, b);
+				return;
+			}
+
+			// The user has specified a different implementation of OnLayout
+			bool handled = Element.OnLayoutDelegate(this, changed, l, t, r, b);
+
+			// If the delegate wasn't able to handle the request, fall back to the default implementation
+			if (!handled)
+				base.OnLayout(changed, l, t, r, b);
+		}
+
+		protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
+		{
+			if (Element?.OnMeasureDelegate == null)
+			{
+				base.OnMeasure(widthMeasureSpec, heightMeasureSpec);
+				return;
+			}
+
+			// The user has specified a different implementation of OnMeasure
+			bool handled = Element.OnMeasureDelegate(this, widthMeasureSpec, heightMeasureSpec);
+
+			// If the delegate wasn't able to handle the request, fall back to the default implementation
+			if (!handled)
+				base.OnMeasure(widthMeasureSpec, heightMeasureSpec);
+		}
+	}
+}
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