Strongly typed handler option and standardize mappers a bit more (#12198)

* strongly typed handler option

* - clean up from meeting notes

* - make spacing consistent

* - PR comments

.nuspec/Xamarin.Forms.MultiTargeting.targets

@@ -2,22 +2,32 @@
   <ItemGroup Condition="$(TargetFramework.StartsWith('Xamarin.iOS')) != true ">
     <Compile Remove="**\*.iOS.cs" />
     <None Include="**\*.iOS.cs" />
+    <Compile Remove="**\iOS\*.cs" />
+    <None Include="**\iOS\*.cs" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('Xamarin.Mac')) != true ">
     <Compile Remove="**\*.Mac.cs" />
     <None Include="**\*.Mac.cs" />
+    <Compile Remove="**\Mac\*.cs" />
+    <None Include="**\Mac\*.cs" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('Xamarin.Mac')) != true And $(TargetFramework.StartsWith('Xamarin.iOS')) != true ">
     <Compile Remove="**\*.MaciOS.cs" />
     <None Include="**\*.MaciOS.cs" />
+    <Compile Remove="**\MaciOS\*.cs" />
+    <None Include="**\MaciOS\*.cs" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('MonoAndroid')) != true ">
     <Compile Remove="**\*.Android.cs" />
     <None Include="**\*.Android.cs" />
+    <Compile Remove="**\Android\*.cs" />
+    <None Include="**\Android\*.cs" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('netstandard')) != true ">
     <Compile Remove="**\*.Standard.cs" />
     <None Include="**\*.Standard.cs" />
+    <Compile Remove="**\Standard\*.cs" />
+    <None Include="**\Standard\*.cs" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('netcoreapp')) != true ">
     <Compile Remove="**\*.Win32.cs" />
@@ -26,13 +36,10 @@
     <None Include="**\*.xaml.cs" />
     <Compile Remove="**\*.xaml" />
     <None Include="**\*.xaml" />
+    <Compile Remove="**\Win32\*.cs" />
+    <None Include="**\Win32\*.cs" />
   </ItemGroup>
-	<ItemGroup>
-		<Folder Include="Platform\MaciOS\" />
-		<Folder Include="Platform\iOS\" />
-		<Folder Include="Platform\Mac\" />
-		<Folder Include="Platform\Android\" />
-	</ItemGroup>
+
   <PropertyGroup Condition="$(TargetFramework.StartsWith('netcoreapp')) == true ">
     <UseWpf>true</UseWpf>
   </PropertyGroup>

src/Platform.Handlers/samples/Sample.Droid/MainActivity.cs

@@ -35,7 +35,7 @@ namespace Sample.Droid
 		{
 			foreach (var view in views)
 			{
-				_page.AddView(view.ToNative(this), new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent));
+				_page.AddView(view.ToNative(this));
 			}
 		}
 

src/Platform.Handlers/samples/Sample/MyApp.cs

@@ -13,7 +13,7 @@ namespace Sample
 
 		public IView CreateView()
 		{
-			return new Button() { Text = "Hello I'm a button", BackgroundColor = Color.Purple };
+			return new Button() { Color = Color.Green , Text = "Hello I'm a button", BackgroundColor = Color.Purple };
 		}
 	}
 }

src/Platform.Handlers/src/Xamarin.Platform.Handlers/ActionMapper.cs

@@ -1,22 +1,24 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Xamarin.Platform.Handlers;
 
 namespace Xamarin.Platform
 {
-	public class ActionMapper<TVirtualView>
+	public class ActionMapper<TVirtualView, TViewHandler>
 			where TVirtualView : IFrameworkElement
+			where TViewHandler : IViewHandler
 	{
-		public ActionMapper(PropertyMapper<TVirtualView> propertyMapper)
+		public ActionMapper(PropertyMapper<TVirtualView, TViewHandler> propertyMapper)
 		{
 			PropertyMapper = propertyMapper;
 		}
 
-		public PropertyMapper<TVirtualView> PropertyMapper { get; }
+		public PropertyMapper<TVirtualView, TViewHandler> PropertyMapper { get; }
 
-		public Action<IViewHandler, TVirtualView> this[string key]
+		public Action<TViewHandler, TVirtualView> this[string key]
 		{
-			set => PropertyMapper._mapper[key] = ((r, v) => value?.Invoke(r, (TVirtualView)v), false);
+			set => PropertyMapper._mapper[key] = ((r, v) => value?.Invoke((TViewHandler)r, (TVirtualView)v), false);
 		}
 	}
 }

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Core/ILabel.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Xamarin.Platform
+{
+	public interface ILabel : IText
+	{
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Button/ButtonHandler.Android.cs

@@ -1,17 +0,0 @@
-using System;
-using AndroidX.Core.View;
-using AndroidX.AppCompat.Widget;
-
-
-namespace Xamarin.Platform.Handlers
-{
-	public partial class ButtonHandler : AbstractViewHandler<IButton, AppCompatButton>
-	{
-		protected override AppCompatButton CreateView() => new AppCompatButton(Context);
-
-		public static void MapText(IViewHandler handler, IButton view) 
-		{
-			((AppCompatButton)handler.NativeView).Text = view.Text;
-		}
-	}
-}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Button/ButtonHandler.Mac.cs

@@ -1,12 +0,0 @@
-using System;
-using AppKit;
-
-namespace Xamarin.Platform.Handlers
-{
-	public partial class ButtonHandler : AbstractViewHandler<IButton, NSButton>
-	{
-		protected override NSButton CreateView() => throw new NotImplementedException();
-
-		public static void MapText(IViewHandler handler, IButton view) { }
-	}
-}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Button/ButtonHandler.Standard.cs

@@ -1,11 +0,0 @@
-using System;
-
-namespace Xamarin.Platform.Handlers
-{
-	public partial class ButtonHandler : AbstractViewHandler<IButton, object>
-	{
-		public static void MapText(IViewHandler handler, IButton view) { }
-
-		protected override object CreateView() => throw new NotImplementedException();
-	}
-}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Button/ButtonHandler.cs

@@ -1,21 +1,42 @@
 using System;
+#if __IOS__
+using NativeView = UIKit.UIButton;
+#elif __MACOS__
+using NativeView = AppKit.NSButton;
+#elif MONOANDROID
+using NativeView = AndroidX.AppCompat.Widget.AppCompatButton;
+#elif NETCOREAPP
+using NativeView = System.Windows.Controls.Button;
+#elif NETSTANDARD
+using NativeView = System.Object;
+#endif
 
 namespace Xamarin.Platform.Handlers
 {
-	public partial class ButtonHandler
+	public partial class ButtonHandler : AbstractViewHandler<IButton, NativeView>
 	{
-		public static PropertyMapper<IButton> ButtonMapper = new PropertyMapper<IButton>(ViewHandler.ViewMapper)
+		public static PropertyMapper<IButton, ButtonHandler> ButtonMapper = new PropertyMapper<IButton, ButtonHandler>(ViewHandler.ViewMapper)
 		{
 			[nameof(IButton.Text)] = MapText,
-			Actions = {
-				["DemoAction"] = DemoAction
-			}
+			[nameof(IButton.Color)] = MapColor
 		};
 
-		private static void DemoAction(IViewHandler arg1, IButton arg2)
+		public static void MapColor(ButtonHandler handler, IButton button)
 		{
+			handler.TypedNativeView.UpdateColor(button);
 		}
 
+		public static void MapText(ButtonHandler handler, IButton button)
+		{
+			handler.TypedNativeView.UpdateText(button);
+		}
+
+#if MONOANDROID
+		protected override NativeView CreateView() => new NativeView(this.Context);
+#else
+		protected override NativeView CreateView() => new NativeView();
+#endif
+
 		public ButtonHandler() : base(ButtonMapper)
 		{
 

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Button/ButtonHandler.iOS.cs

@@ -1,15 +0,0 @@
-using System;
-using UIKit;
-
-namespace Xamarin.Platform.Handlers
-{
-	public partial class ButtonHandler : AbstractViewHandler<IButton, UIButton>
-	{
-		protected override UIButton CreateView() => new UIButton();
-
-		public static void MapText(IViewHandler handler, IButton view)
-		{
-			((UIButton)handler.NativeView).SetText(view.Text);
-		}
-	}
-}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Handlers/Label/LabelHandler.cs

@@ -0,0 +1,43 @@
+using System;
+#if __IOS__
+using NativeView = UIKit.UILabel;
+#elif __MACOS__
+using NativeView = AppKit.NSTextField;
+#elif MONOANDROID
+using NativeView = Android.Widget.TextView;
+#elif NETCOREAPP
+using NativeView = System.Windows.Controls.TextBlock;
+#elif NETSTANDARD
+using NativeView = System.Object;
+#endif
+
+namespace Xamarin.Platform.Handlers
+{
+	public partial class LabelHandler : AbstractViewHandler<ILabel, NativeView>
+	{
+		public static PropertyMapper<ILabel, LabelHandler> LabelMapper = new PropertyMapper<ILabel, LabelHandler>(ViewHandler.ViewMapper)
+		{
+			[nameof(ILabel.Color)] = MapColor
+		};
+
+		public static void MapColor(LabelHandler handler, ILabel Label)
+		{
+		}
+
+#if MONOANDROID
+		protected override NativeView CreateView() => new NativeView(this.Context);
+#else
+		protected override NativeView CreateView() => new NativeView();
+#endif
+
+		public LabelHandler() : base(LabelMapper)
+		{
+
+		}
+
+		public LabelHandler(PropertyMapper mapper) : base(mapper ?? LabelMapper)
+		{
+
+		}
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Platform/Android/ButtonExtensions.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using AndroidX.AppCompat.Widget;
+
+namespace Xamarin.Platform
+{
+	public static class ButtonExtensions
+	{
+		public static void UpdateColor(this AppCompatButton appCompatButton, IButton button) => 
+			appCompatButton.SetTextColor(button.Color.ToNative());		
+
+		public static void UpdateText(this AppCompatButton appCompatButton, IButton button) =>
+			appCompatButton.Text = button.Text;
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Platform/Mac/ButtonExtensions.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using AndroidX.AppCompat.Widget;
+
+namespace Xamarin.Platform
+{
+	public static class ButtonExtensions
+	{
+		public static void UpdateColor(this IButton button, NSButton button)
+		{
+		}
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Platform/Standard/ButtonExtensions.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Xamarin.Platform
+{
+	public static class ButtonExtensions
+	{
+		public static void UpdateColor(this object nothing, IButton button)
+		{
+
+		}
+
+		public static void UpdateText(this object nothing, IButton button)
+		{
+
+		}
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Platform/iOS/ButtonExtensions.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using UIKit;
+
+namespace Xamarin.Platform
+{
+	public static class ButtonExtensions
+	{
+		public static void UpdateColor(this UIButton nativeButton, IButton button)
+		{
+			// appCompatButton.SetTextColor(button.Color.ToNative());
+		}
+
+		public static void UpdateText(this UIButton nativeButton, IButton button) => nativeButton.SetText(button.Text);
+	}
+}

src/Platform.Handlers/src/Xamarin.Platform.Handlers/PropertyMapper.cs

@@ -64,8 +64,9 @@ namespace Xamarin.Platform
 		public virtual IReadOnlyList<string> UpdateKeys => updateKeys ?? PopulateKeys(ref updateKeys);
 	}
 
-	public class PropertyMapper<TVirtualView> : PropertyMapper, IEnumerable
+	public class PropertyMapper<TVirtualView, TViewHandler> : PropertyMapper, IEnumerable
 		where TVirtualView : IFrameworkElement
+		where TViewHandler : IViewHandler
 	{
 		private PropertyMapper chained;
 		public PropertyMapper Chained
@@ -85,7 +86,7 @@ namespace Xamarin.Platform
 
 		public bool IsReadOnly => false;
 
-		public Action<IViewHandler, TVirtualView> this[string key]
+		public Action<TViewHandler, TVirtualView> this[string key]
 		{
 			set => Add(key, value, true);
 		}
@@ -99,10 +100,10 @@ namespace Xamarin.Platform
 			Chained = chained;
 		}
 
-		ActionMapper<TVirtualView> actions;
-		public ActionMapper<TVirtualView> Actions
+		ActionMapper<TVirtualView, TViewHandler> actions;
+		public ActionMapper<TVirtualView, TViewHandler> Actions
 		{
-			get => actions ??= new ActionMapper<TVirtualView>(this);
+			get => actions ??= new ActionMapper<TVirtualView, TViewHandler>(this);
 		}
 
 		protected override void ClearKeyCache()
@@ -121,17 +122,27 @@ namespace Xamarin.Platform
 				return Chained?.Get(key) ?? (null, false);
 		}
 
-		public void Add(string key, Action<IViewHandler, TVirtualView> action)
+		public void Add(string key, Action<TViewHandler, TVirtualView> action)
 			=> this[key] = action;
 
-		public void Add(string key, Action<IViewHandler, TVirtualView> action, bool ignoreOnStartup)
-			=> _mapper[key] = ((r, v) => action?.Invoke(r, (TVirtualView)v), ignoreOnStartup);
-
-
-
+		public void Add(string key, Action<TViewHandler, TVirtualView> action, bool ignoreOnStartup)
+			=> _mapper[key] = ((r, v) => action?.Invoke((TViewHandler)r, (TVirtualView)v), ignoreOnStartup);
 
 		IEnumerator IEnumerable.GetEnumerator() => _mapper.GetEnumerator();
+	}
 
 
+
+
+	public class PropertyMapper<TVirtualView> : PropertyMapper<TVirtualView, IViewHandler>
+		where TVirtualView : IFrameworkElement
+	{
+		public PropertyMapper()
+		{
+		}
+
+		public PropertyMapper(PropertyMapper chained) : base(chained)
+		{
+		}
 	}
 }

src/Platform.Handlers/tests/Xamarin.Platform.Handlers.Tests/PropertyMapperTests.cs

@@ -130,5 +130,28 @@ namespace Xamarin.Platform.Handlers.Tests
 			Assert.False(mapperActionWasCalled);
 			Assert.True(wasMapper2Called);
 		}
+
+
+
+		[Test]
+		public void GenericMappersWorks()
+		{
+			bool wasMapper1Called = false;
+			bool wasMapper2Called = false;
+			var mapper1 = new PropertyMapper<IView, IViewHandler>
+			{
+				[nameof(IView.BackgroundColor)] = (r, v) => wasMapper1Called = true
+			};
+
+			var mapper2 = new PropertyMapper<IButton, ButtonHandler>(mapper1)
+			{
+				[nameof(IButton.Color)] = (r, v) => wasMapper2Called = true
+			};
+
+			mapper2.UpdateProperties(null, new Button());
+
+			Assert.True(wasMapper1Called);
+			Assert.True(wasMapper2Called);
+		}
 	}
 }