Detect Points changes in Polygon (#11576)

Co-authored-by: Rui Marinho <[email protected]>

fixes #11563

Author: jsuarezruiz

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue11563.cs

@@ -0,0 +1,71 @@
+using Xamarin.Forms.Internals;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Shapes;
+using System.Collections.Generic;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.Shape)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 11563,
+		"[Bug] Polygon.Points doesn't respond to CollectionChanged events",
+		PlatformAffected.All)]
+	public class Issue11563 : TestContentPage
+	{
+		public Issue11563()
+		{
+#if APP
+			Device.SetFlags(new List<string> { ExperimentalFlags.BrushExperimental, ExperimentalFlags.ShapesExperimental });
+#endif
+		}
+
+		protected override void Init()
+		{
+			var layout = new StackLayout();
+
+			var instructions = new Label
+			{
+				Padding = 12,
+				BackgroundColor = Color.Black,
+				TextColor = Color.White,
+				Text = "Tap the button, if the Polygon is updated, the test has passed."
+			};
+
+			var button = new Button
+			{
+				Text = "Update Polygon points"
+			};
+
+			var points  = new PointCollection() { new Point(10, 10), new Point(100, 50), new Point(100, 95), new Point(10, 95) };
+
+			var polygon = new Polygon
+			{
+				HeightRequest = 100,
+				WidthRequest = 100,
+				StrokeThickness = 2,
+				Stroke = Brush.Red,
+				Points = points
+			};
+
+			layout.Children.Add(instructions);
+			layout.Children.Add(button);
+			layout.Children.Add(polygon);
+
+			Content = layout;
+
+			button.Clicked += (sender, args) =>
+			{
+				if (points.Count > 1)
+					points.RemoveAt(1);
+			};
+		}
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1462,6 +1462,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue11291.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11244.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11272.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue11563.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11547.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11247.cs" />
   </ItemGroup>

Xamarin.Forms.Platform.Android/Shapes/PolygonRenderer.cs

@@ -1,4 +1,5 @@
-using System.ComponentModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
 using Android.Content;
 using Xamarin.Forms.Shapes;
 using static Android.Graphics.Path;
@@ -24,6 +25,9 @@ protected override void OnElementChanged(ElementChangedEventArgs<Polygon> args)
 
             if (args.NewElement != null)
             {
+                var points = args.NewElement.Points;
+                points.CollectionChanged += OnCollectionChanged;
+
                 UpdatePoints();
                 UpdateFillRule();
             }
@@ -39,6 +43,20 @@ protected override void OnElementPropertyChanged(object sender, PropertyChangedE
                 UpdateFillRule();
         }
 
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+
+            if (disposing)
+            {
+                if (Element != null)
+                {
+                    var points = Element.Points;
+                    points.CollectionChanged -= OnCollectionChanged;
+                }
+            }
+        }
+
         void UpdatePoints()
         {
             Control.UpdatePoints(Element.Points);
@@ -48,6 +66,11 @@ void UpdateFillRule()
         {
             Control.UpdateFillMode(Element.FillRule == FillRule.Nonzero);
         }
+
+        void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            UpdatePoints();
+        }
     }
 
     public class PolygonView : ShapeView

Xamarin.Forms.Platform.UAP/Shapes/PolygonRenderer.cs

@@ -1,5 +1,6 @@
 using System.ComponentModel;
 using Xamarin.Forms.Shapes;
+using System.Collections.Specialized;
 
 #if WINDOWS_UWP
 using WFillRule = Windows.UI.Xaml.Media.FillRule;
@@ -27,6 +28,9 @@ protected override void OnElementChanged(ElementChangedEventArgs<Polygon> args)
 
 			if (args.NewElement != null)
 			{
+				var points = args.NewElement.Points;
+				points.CollectionChanged += OnCollectionChanged;
+
 				UpdatePoints();
 				UpdateFillRule();
 			}
@@ -42,6 +46,20 @@ protected override void OnElementPropertyChanged(object sender, PropertyChangedE
 				UpdateFillRule();
 		}
 
+		protected override void Dispose(bool disposing)
+		{
+			base.Dispose(disposing);
+
+			if (disposing)
+			{
+				if (Element != null)
+				{
+					var points = Element.Points;
+					points.CollectionChanged -= OnCollectionChanged;
+				}
+			}
+		}
+
 		void UpdatePoints()
 		{
 			Control.Points = Element.Points.ToWindows();
@@ -53,5 +71,10 @@ void UpdateFillRule()
 				WFillRule.EvenOdd :
 				WFillRule.Nonzero;
 		}
+
+		void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+		{
+			UpdatePoints();
+		}
 	}
 }

Xamarin.Forms.Platform.iOS/Shapes/PolygonRenderer.cs

@@ -1,4 +1,5 @@
-using System.ComponentModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
 using CoreGraphics;
 using Xamarin.Forms.Shapes;
 
@@ -27,12 +28,15 @@ protected override void OnElementChanged(ElementChangedEventArgs<Polygon> args)
 
             if (args.NewElement != null)
             {
+                var points = args.NewElement.Points;
+                points.CollectionChanged += OnCollectionChanged;
+
                 UpdatePoints();
                 UpdateFillRule();
             }
         }
 
-        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs args)
+		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs args)
         {
             base.OnElementPropertyChanged(sender, args);
 
@@ -42,7 +46,21 @@ protected override void OnElementPropertyChanged(object sender, PropertyChangedE
                 UpdateFillRule();
         }
 
-        void UpdatePoints()
+		protected override void Dispose(bool disposing)
+		{
+			base.Dispose(disposing);
+
+            if (disposing)
+            {
+                if (Element != null)
+                {
+                    var points = Element.Points;
+                    points.CollectionChanged -= OnCollectionChanged;
+                }
+            }
+		}
+
+		void UpdatePoints()
         {
             Control.UpdatePoints(Element.Points.ToCGPoints());
         }
@@ -51,6 +69,11 @@ public void UpdateFillRule()
         {
             Control.UpdateFillMode(Element.FillRule == FillRule.Nonzero);
         }
+
+        void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            UpdatePoints();
+        }
     }
 
     public class PolygonView : ShapeView
@@ -69,4 +92,4 @@ public void UpdateFillMode(bool fillMode)
             ShapeLayer.UpdateFillMode(fillMode);
         }
     }
-}
+}