[Android] fix removed NativeSizeChanged (#4395)

Xamarin.Forms.Controls/GalleryPages/ImageGallery.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
 
@@ -17,7 +18,7 @@ namespace Xamarin.Forms.Controls
 			var disabled = new Image { Source = ImageSource.FromFile("cover1.jpg") };
 			var rotate = new Image { Source = ImageSource.FromFile("cover1.jpg") };
 			var transparent = new Image { Source = ImageSource.FromFile("cover1.jpg") };
-			var embedded = new Image { Source = ImageSource.FromResource ("Xamarin.Forms.Controls.ControlGalleryPages.crimson.jpg", typeof (ImageGallery)) };
+			var embedded = new Image { Source = ImageSource.FromResource("Xamarin.Forms.Controls.GalleryPages.crimson.jpg", typeof(ImageGallery).GetTypeInfo().Assembly) };
 
 			// let the stack shrink the images
 			normal.MinimumHeightRequest = normal.MinimumHeightRequest = 10;
@@ -30,22 +31,37 @@ namespace Xamarin.Forms.Controls
 			rotate.GestureRecognizers.Add(new TapGestureRecognizer { Command = new Command(o => rotate.RelRotateTo(180)) });
 			transparent.Opacity = .5;
 
-			Content = new StackLayout {
+			Content =
+				new ScrollView()
+				{
+					Content = new StackLayout
+					{
 						Orientation = StackOrientation.Horizontal,
-				Children = {
-					new StackLayout {
+						Children =
+						{
+							new StackLayout
+							{
 								//MinimumWidthRequest = 20,
 								HorizontalOptions = LayoutOptions.FillAndExpand,
-						Children = {
+								Children =
+								{
+									new Label(){ Text = "Normal"},
 									normal,
+									new Label(){ Text = "Disabled"},
 									disabled,
+									new Label(){ Text = "Transparent"},
 									transparent,
+									new Label(){ Text = "Rotate"},
 									rotate,
+									new Label(){ Text = "Embedded"},
 									embedded,
-							new StackLayout {
+									new Label(){ Text = "Horizontal"},
+									new StackLayout
+									{
 										HeightRequest = 30,
 										Orientation = StackOrientation.Horizontal,
-								Children = {
+										Children =
+										{
 											new Image {Source = "cover1.jpg"},
 											new Image {Source = "cover1.jpg"},
 											new Image {Source = "cover1.jpg"},
@@ -54,9 +70,11 @@ namespace Xamarin.Forms.Controls
 									}
 								}
 							},
-					new StackLayout {
+							new StackLayout
+							{
 								WidthRequest = 30,
-						Children = {
+								Children =
+								{
 									new Image {Source = "cover1.jpg"},
 									new Image {Source = "cover1.jpg"},
 									new Image {Source = "cover1.jpg"},
@@ -65,6 +83,7 @@ namespace Xamarin.Forms.Controls
 							}
 
 						}
+					}
 				};
 		}
 	}

Xamarin.Forms.Platform.Android/Extensions/ImageViewExtensions.cs

@@ -80,6 +80,7 @@ namespace Xamarin.Forms.Platform.Android
 
 			bitmap?.Dispose();
 			imageController?.SetIsLoading(false);
+			imageController?.NativeSizeChanged();
 		}
 	}
 }