Moved ui loop methods to a new class

Minor fixes

GtkTest/Main.cs

@@ -25,6 +25,7 @@
 // THE SOFTWARE.
 using System;
 using Samples;
+using Xwt;
 
 namespace GtkTest
 {
@@ -32,7 +33,7 @@ namespace GtkTest
 	{
 		public static void Main (string[] args)
 		{
-			App.Run ("Xwt.GtkBackend.GtkEngine, Xwt.Gtk, Version=1.0.0.0");
+			App.Run (ToolkitType.Gtk);
 		}
 	}
 }

MacTest/Main.cs

@@ -10,7 +10,7 @@ namespace MacTest
 	{
 		static void Main (string [] args)
 		{
-			App.Run ("Xwt.Mac.MacEngine, Xwt.Mac, Version=1.0.0.0");
+			App.Run (ToolkitType.Cocoa);
 		}
 	}
 }	

Samples/App.cs

@@ -7,9 +7,9 @@ namespace Samples
 {
 	public class App
 	{
-		public static void Run (string engineType)
+		public static void Run (ToolkitType type)
 		{
-			Application.Initialize (engineType);
+			Application.Initialize (type);
 			
 			MainWindow w = new MainWindow ();
 			w.Title = "Xwt Demo Application";

WpfTest/Main.cs

@@ -25,6 +25,7 @@
 
 using System;
 using Samples;
+using Xwt;
 
 namespace WpfTest
 {
@@ -33,7 +34,7 @@ namespace WpfTest
 		[STAThread]
 		public static void Main(string[] args)
 		{
-			App.Run ("Xwt.WPFBackend.WPFEngine, Xwt.WPF, Version=1.0.0.0");
+			App.Run (ToolkitType.Wpf);
 		}
 	}
 }

Xwt/Xwt.csproj

@@ -377,7 +377,4 @@
     </MonoDevelop>
   </ProjectExtensions>
   <ItemGroup />
-  <ItemGroup>
-    <Folder Include="Xwt.Engine\" />
-  </ItemGroup>
 </Project>

Xwt/Xwt/Application.cs

@@ -36,6 +36,7 @@ namespace Xwt
 	{
 		static Toolkit toolkit;
 		static ToolkitEngineBackend engine;
+		static UILoop mainLoop;
 
 		static readonly TaskScheduler taskScheduler = new XwtTaskScheduler ();
 
@@ -43,6 +44,10 @@ namespace Xwt
 			get { return taskScheduler; }
 		}
 
+		public static UILoop MainLoop {
+			get { return mainLoop; }
+		}
+
 		internal static System.Threading.Thread UIThread {
 			get;
 			private set;
@@ -55,13 +60,20 @@ namespace Xwt
 			Initialize (null);
 		}
 		
+		public static void Initialize (ToolkitType type)
+		{
+			Initialize (Toolkit.GetBackendType (type));
+		}
+
 		public static void Initialize (string backendType)
 		{
 			if (engine != null)
 				return;
 
 			toolkit = Toolkit.Load (backendType);
+			toolkit.SetActive ();
 			engine = toolkit.Backend;
+			mainLoop = new UILoop (toolkit);
 
 			UIThread = System.Threading.Thread.CurrentThread;
 		}
@@ -150,21 +162,6 @@ namespace Xwt
 			return t;
 		}
 
-		public static void DispatchPendingEvents ()
-		{
-			try {
-				toolkit.ExitUserCode (null);
-				engine.DispatchPendingEvents ();
-			} finally {
-				toolkit.EnterUserCode ();
-			}
-		}
-
-		public static void QueueExitAction (Action a)
-		{
-			Toolkit.CurrentEngine.QueueExitAction (a);
-		}
-		
 		public static StatusIcon CreateStatusIcon ()
 		{
 			return new StatusIcon ();
@@ -180,46 +177,7 @@ namespace Xwt
 				Application.engine.CancelTimerInvoke (Id);
 			}
 		}
-		
-		static bool LoadBackend (string type)
-		{
-			int i = type.IndexOf (',');
-			string assembly = type.Substring (i+1).Trim ();
-			type = type.Substring (0, i).Trim ();
-			try {
-				Assembly asm = Assembly.Load (assembly);
-				if (asm != null) {
-					Type t = asm.GetType (type);
-					if (t != null) {
-						engine = (ToolkitEngineBackend) Activator.CreateInstance (t);
-						return true;
-					}
-				}
-			}
-			catch (Exception ex) {
-				Console.WriteLine (ex);
-			}
-			return false;
-		}
-		
-		static void InitBackend (string type)
-		{
-			toolkit.EnterUserCode ();
-			if (type != null && LoadBackend (type))
-				return;
-			
-			if (LoadBackend ("Xwt.GtkBackend.GtkEngine, Xwt.Gtk, Version=1.0.0.0"))
-				return;
-			
-			if (LoadBackend ("Xwt.Mac.MacEngine, Xwt.Mac, Version=1.0.0.0"))
-				return;
-			
-			if (LoadBackend ("Xwt.WPFBackend.WPFEngine, Xwt.WPF, Version=1.0.0.0"))
-				return;
-			
-			throw new InvalidOperationException ("Xwt engine not found");
-		}
-		
+
 		internal static void NotifyException (Exception ex)
 		{
 			var unhandledException = UnhandledException;
@@ -234,6 +192,32 @@ namespace Xwt
 		}
 	}
 
+	public class UILoop
+	{
+		Toolkit toolkit;
+
+		internal UILoop (Toolkit toolkit)
+		{
+			this.toolkit = toolkit;
+		}
+
+		public void DispatchPendingEvents ()
+		{
+			try {
+				toolkit.ExitUserCode (null);
+				toolkit.Backend.DispatchPendingEvents ();
+			} finally {
+				toolkit.EnterUserCode ();
+			}
+		}
+
+		public void QueueExitAction (Action a)
+		{
+			toolkit.QueueExitAction (a);
+		}
+	}
+
+
 	public enum ToolkitType
 	{
 		Gtk,

Xwt/Xwt/ListView.cs

@@ -109,7 +109,7 @@ namespace Xwt
 			}
 			set {
 				if (dataSource != value) {
-					Backend.SetSource (dataSource, dataSource is IFrontend ? (IBackend)BackendHost.ToolkitEngine.GetSafeBackend (dataSource) : null);
+					Backend.SetSource (value, value is IFrontend ? (IBackend)BackendHost.ToolkitEngine.GetSafeBackend (value) : null);
 					dataSource = value;
 				}
 			}

Xwt/Xwt/Toolkit.cs

@@ -65,13 +65,13 @@ namespace Xwt
 			if (fullTypeName != null && t.LoadBackend (fullTypeName))
 				return t;
 			
-			if (t.LoadBackend (ToolkitType.Gtk))
+			if (t.LoadBackend (GetBackendType (ToolkitType.Gtk)))
 				return t;
 			
-			if (t.LoadBackend (ToolkitType.Cocoa))
+			if (t.LoadBackend (GetBackendType (ToolkitType.Cocoa)))
 				return t;
 			
-			if (t.LoadBackend (ToolkitType.Wpf))
+			if (t.LoadBackend (GetBackendType (ToolkitType.Wpf)))
 				return t;
 			
 			throw new InvalidOperationException ("Xwt engine not found");
@@ -80,21 +80,21 @@ namespace Xwt
 		public static Toolkit Load (ToolkitType type)
 		{
 			Toolkit t = new Toolkit ();
-			if (t.LoadBackend (type))
+			if (t.LoadBackend (GetBackendType (type)))
 				return t;
 			else
 				throw new InvalidOperationException ("Xwt engine not found");
 		}
 
-		bool LoadBackend (ToolkitType type)
+		internal static string GetBackendType (ToolkitType type)
 		{
 			switch (type) {
 			case ToolkitType.Gtk:
-				return LoadBackend ("Xwt.GtkBackend.GtkEngine, Xwt.Gtk, Version=1.0.0.0");
+				return "Xwt.GtkBackend.GtkEngine, Xwt.Gtk, Version=1.0.0.0";
 			case ToolkitType.Cocoa:
-				return LoadBackend ("Xwt.Mac.MacEngine, Xwt.Mac, Version=1.0.0.0");
+				return "Xwt.Mac.MacEngine, Xwt.Mac, Version=1.0.0.0";
 			case ToolkitType.Wpf:
-				return LoadBackend ("Xwt.WPFBackend.WPFEngine, Xwt.WPF, Version=1.0.0.0");
+				return "Xwt.WPFBackend.WPFEngine, Xwt.WPF, Version=1.0.0.0";
 			default:
 				throw new ArgumentException ("Invalid toolkit type");
 			}
@@ -135,6 +135,11 @@ namespace Xwt
 			ImageBackendHandler = Backend.CreateSharedBackend<ImageBackendHandler> (typeof(Image));
 		}
 
+		internal void SetActive ()
+		{
+			currentEngine = this;
+		}
+
 		public object GetNativeWidget (Widget w)
 		{
 			ValidateObject (w);

Xwt/Xwt/TreeView.cs

@@ -128,7 +128,7 @@ namespace Xwt
 			}
 			set {
 				if (dataSource != value) {
-					Backend.SetSource (dataSource, dataSource is IFrontend ? (IBackend)BackendHost.ToolkitEngine.GetSafeBackend (dataSource) : null);
+					Backend.SetSource (value, value is IFrontend ? (IBackend)BackendHost.ToolkitEngine.GetSafeBackend (value) : null);
 					dataSource = value;
 				}
 			}

Xwt/Xwt/Widget.cs

@@ -1080,7 +1080,7 @@ namespace Xwt
 				QueueForSizeCheck (Parent);
 				if (!delayedSizeNegotiationRequested) {
 					delayedSizeNegotiationRequested = true;
-					Application.QueueExitAction (DelayedResizeRequest);
+					Application.MainLoop.QueueExitAction (DelayedResizeRequest);
 				}
 			}
 			else if (ParentWindow is Window) {
@@ -1098,7 +1098,7 @@ namespace Xwt
 			resizeWindows.Add ((Window)window);
 			if (!delayedSizeNegotiationRequested) {
 				delayedSizeNegotiationRequested = true;
-				Application.QueueExitAction (DelayedResizeRequest);
+				Application.MainLoop.QueueExitAction (DelayedResizeRequest);
 			}
 		}