Added in Missing HotReload

src/HotUI/HotReloadHelper.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace HotUI {
+	public static class HotReloadHelper {
+		static HotReloadHelper()
+		{
+			IsEnabled = Debugger.IsAttached;
+		}
+		public static bool IsEnabled { get; set; }
+
+		public static void Register(View view, params object[] parameters)
+		{
+			if (!IsEnabled)
+				return;
+			currentViews [view] = parameters;
+		}
+
+		public static void UnRegister(View view)
+		{
+			if (!IsEnabled)
+				return;
+			currentViews.Remove (view);
+		}
+
+		public static View GetReplacedView(View view)
+		{
+			if (!IsEnabled)
+				return view;
+			if (!replacedViews.TryGetValue (view.GetType ().FullName, out var newViewType))
+				return view;
+
+			currentViews.TryGetValue (view, out var parameters);
+			var newView = parameters?.Length > 0 ? Activator.CreateInstance (newViewType, args: parameters) : Activator.CreateInstance (newViewType);
+			//TODO: Apply state!
+			return (View)newView;
+		}
+
+		static Dictionary<string, Type> replacedViews = new Dictionary<string, Type> ();
+		static Dictionary<View, object []> currentViews = new Dictionary<View, object []> ();
+		public static void RegisterReplacedView(string oldViewType, Type newViewType)
+		{
+			if (!IsEnabled)
+				return;
+			replacedViews [oldViewType] = newViewType;
+		}
+		public static void TriggerReload()
+		{
+			var roots = View.ActiveViews.Where (x => x.Parent == null).ToList();
+			foreach(var view in roots) {
+				Device.InvokeOnMainThread (view.Reload);
+			}
+		}
+	}
+}

tests/HotUI.Tests/HotReloadTestsNoParameters.cs

@@ -0,0 +1,41 @@
+using System;
+using Xunit;
+
+namespace HotUI.Tests {
+	public class HotReloadTests {
+
+		public class MyOrgView : View {
+			public const string TextValue = "Hello!";
+			public MyOrgView ()
+			{
+				this.Body = () => new Text (TextValue);
+			}
+		}
+		public class MyNewView : View {
+			public const string TextValue = "Goodbye!";
+			public MyNewView ()
+			{
+				this.Body = () => new Text (TextValue);
+			}
+		}
+
+		public HotReloadTests ()
+		{
+			HotReloadHelper.IsEnabled = true;
+		}
+
+		[Fact]
+		public void HotReloadRegisterReplacedViewReplacesView ()
+		{
+			var orgView = new MyOrgView ();
+			var orgText = orgView.GetView () as Text;
+			Assert.Equal (MyOrgView.TextValue, orgText.Value);
+
+			HotReloadHelper.RegisterReplacedView (typeof (MyOrgView).FullName, typeof (MyNewView));
+			var newText = orgView.GetView () as Text;
+
+			Assert.Equal (MyNewView.TextValue, newText.Value);
+
+		}
+	}
+}

tests/HotUI.Tests/HotReloadWithParameters.cs

@@ -0,0 +1,41 @@
+using System;
+using Xunit;
+
+namespace HotUI.Tests {
+	public class HotReloadWithParameters : TestBase {
+		public class MyOrgView : View {
+			public const string TextValue = "Hello!";
+			public MyOrgView (string text)
+			{
+				HotReloadHelper.Register (this, text);
+				this.Body = () => new Text (text);
+			}
+		}
+		public class MyNewView : View {
+			public MyNewView (string text)
+			{
+				HotReloadHelper.Register (this, text);
+				this.Body = () => new Text (text);
+			}
+		}
+
+		public HotReloadWithParameters ()
+		{
+			HotReloadHelper.IsEnabled = true;
+		}
+
+		[Fact]
+		public void HotReloadRegisterReplacedViewReplacesView ()
+		{
+			var orgView = new MyOrgView (MyOrgView.TextValue);
+			var orgText = orgView.GetView () as Text;
+			Assert.Equal (MyOrgView.TextValue, orgText.Value);
+
+			HotReloadHelper.RegisterReplacedView (typeof (MyOrgView).FullName, typeof (MyNewView));
+			var newText = orgView.GetView () as Text;
+
+			Assert.Equal (MyOrgView.TextValue, newText.Value);
+
+		}
+	}
+}