Merge branch '3.2.0' into 3.3.0

Xamarin.Forms.Platform.Android/Renderers/BoxRenderer.cs

@@ -59,8 +59,7 @@ namespace Xamarin.Forms.Platform.Android
 			if (colorToSet == Color.Default)
 				colorToSet = Element.BackgroundColor;
 
-			if (_backgroundDrawable == null)
-				_backgroundDrawable = new GradientDrawable();
+			if (_backgroundDrawable != null) {
 
 				if (colorToSet != Color.Default)
 					_backgroundDrawable.SetColor(colorToSet.ToAndroid());
@@ -69,6 +68,12 @@ namespace Xamarin.Forms.Platform.Android
 
 				this.SetBackground(_backgroundDrawable);
 			}
+			else {
+				if (colorToSet == Color.Default)
+					colorToSet = Element.BackgroundColor;
+				SetBackgroundColor(colorToSet.ToAndroid(Color.Transparent));
+			}
+		}
 
 		protected override void Dispose(bool disposing)
 		{
@@ -101,11 +106,14 @@ namespace Xamarin.Forms.Platform.Android
 		void UpdateCornerRadius()
 		{
 			var cornerRadius = Element.CornerRadius;
-
-			if (Background is GradientDrawable backgroundGradient)
-			{
-				var cornerRadii = new[]
-				{
+			if (cornerRadius == new CornerRadius(0d)) {
+				_backgroundDrawable?.Dispose();
+				_backgroundDrawable = null;
+			}
+			else {
+				this.SetBackground(_backgroundDrawable = new GradientDrawable());
+				if (Background is GradientDrawable backgroundGradient) {
+					var cornerRadii = new[] {
 						(float)(cornerRadius.TopLeft),
 						(float)(cornerRadius.TopLeft),
 
@@ -122,5 +130,8 @@ namespace Xamarin.Forms.Platform.Android
 					backgroundGradient.SetCornerRadii(cornerRadii);
 				}
 			}
+
+			UpdateBackgroundColor();
+		}
 	}
 }