GtkDemo: Add a Spinner demo

As the other samples in GtkDemo, this is straight translation of the C
demos in the GTK+ source tree under demos/gtk-demo/.

sample/GtkDemo/DemoSpinner.cs

@@ -0,0 +1,73 @@
+/* Spinner
+ *
+ * GtkSpinner allows to show that background activity is on-going.
+ *
+ */
+
+using System;
+using Gtk;
+
+namespace GtkDemo
+{
+	[Demo ("Spinner", "DemoSpinner.cs")]
+	public class DemoSpinner : Dialog
+	{
+		Spinner spinner_sensitive;
+		Spinner spinner_unsensitive;
+
+		public DemoSpinner () : base ("Spinner", null, DialogFlags.DestroyWithParent)
+		{
+			Resizable = false;
+
+			VBox vbox = new VBox (false, 5);
+			vbox.BorderWidth = 5;
+			ContentArea.PackStart (vbox, true, true, 0);
+
+			/* Sensitive */
+			HBox hbox = new HBox (false, 5);
+			spinner_sensitive = new Spinner ();
+			hbox.Add (spinner_sensitive);
+			hbox.Add (new Entry ());
+			vbox.Add (hbox);
+
+			/* Disabled */
+			hbox = new HBox (false, 5);
+			spinner_unsensitive = new Spinner ();
+			spinner_unsensitive.Sensitive = false;
+			hbox.Add (spinner_unsensitive);
+			hbox.Add (new Entry ());
+			vbox.Add (hbox);
+
+			Button btn_play = new Button ();
+			btn_play.Label = "Play";
+			btn_play.Clicked += OnPlayClicked;
+			vbox.Add (btn_play);
+
+			Button btn_stop = new Button ();
+			btn_stop.Label = "Stop";
+			btn_stop.Clicked += OnStopClicked;
+			vbox.Add (btn_stop);
+
+			AddButton (Stock.Close, ResponseType.Close);
+
+			OnPlayClicked (null, null);
+
+			ShowAll ();
+			Run ();
+			Destroy ();
+		}
+
+		private void OnPlayClicked (object sender, EventArgs e)
+		{
+			spinner_sensitive.Start ();
+			spinner_unsensitive.Start ();
+		}
+
+		private void OnStopClicked (object sender, EventArgs e)
+		{
+			spinner_sensitive.Stop ();
+			spinner_unsensitive.Stop ();
+		}
+	}
+}
+

sample/GtkDemo/Makefile.am

@@ -36,6 +36,7 @@ sources = \
 	DemoPixbuf.cs			\
 	DemoRotatedText.cs		\
 	DemoSizeGroup.cs		\
+	DemoSpinner.cs			\
 	DemoStockBrowser.cs		\
 	DemoTextView.cs			\
 	DemoTreeStore.cs		\

sample/sample.csproj

@@ -109,6 +109,7 @@
     <Compile Include="gtk-gio\MountOperation.cs" />
     <Compile Include="CairoPng.cs" />
     <Compile Include="valtest\Gtksharp\Valobj.cs" />
+    <Compile Include="GtkDemo\DemoSpinner.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>