Add BoxViewClock sample

Ooui.Forms/Forms.cs

@@ -110,7 +110,13 @@ namespace Xamarin.Forms
 
             public void StartTimer (TimeSpan interval, Func<bool> callback)
             {
-                throw new NotImplementedException ();
+                Timer timer = null;
+                timer = new Timer ((_ => {
+                    if (!callback ()) {
+                        timer?.Dispose ();
+                        timer = null;
+                    }
+                }), null, (int)interval.TotalMilliseconds, (int)interval.TotalMilliseconds);
             }
         }
 

PlatformSamples/AspNetCoreMvc/AspNetCoreMvc.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
+    <PackageReference Include="Xamarin.Forms" Version="2.4.0.38779" />
   </ItemGroup>
 
   <ItemGroup>
@@ -19,5 +20,6 @@
     <ProjectReference Include="..\..\Ooui.AspNetCore\Ooui.AspNetCore.csproj" />
     <ProjectReference Include="..\..\Ooui\Ooui.csproj" />
     <ProjectReference Include="..\..\Samples\Samples.csproj" />
+    <ProjectReference Include="..\..\Ooui.Forms\Ooui.Forms.csproj" />
   </ItemGroup>
 </Project>

PlatformSamples/AspNetCoreMvc/Startup.cs

@@ -39,6 +39,8 @@ namespace AspNetCoreMvc
 
             app.UseOoui ();
 
+            Xamarin.Forms.Forms.Init ();
+
             app.UseMvc (routes => {
                 routes.MapRoute (
                     name: "default",

Samples/BoxViewClockSample.cs

@@ -0,0 +1,130 @@
+using System;
+using Xamarin.Forms;
+
+namespace Samples
+{
+    public class BoxViewClockSample : ISample
+    {
+        public string Title => "Xamarin.Forms BoxViewClock";
+
+        public Ooui.Element CreateElement ()
+        {
+            return new BoxViewClockPage ().CreateElement ();
+        }
+
+        class BoxViewClockPage : ContentPage
+        {
+            // Structure for storing information about the three hands.
+            struct HandParams
+            {
+                public HandParams (double width, double height, double offset) : this ()
+                {
+                    Width = width;
+                    Height = height;
+                    Offset = offset;
+                }
+
+                public double Width { private set; get; }   // fraction of radius
+                public double Height { private set; get; }  // ditto
+                public double Offset { private set; get; }  // relative to center pivot
+            }
+
+            static readonly HandParams secondParams = new HandParams (0.02, 1.1, 0.85);
+            static readonly HandParams minuteParams = new HandParams (0.05, 0.8, 0.9);
+            static readonly HandParams hourParams = new HandParams (0.125, 0.65, 0.9);
+
+            BoxView[] tickMarks = new BoxView[60];
+            BoxView secondHand, minuteHand, hourHand;
+
+            public BoxViewClockPage ()
+            {
+                AbsoluteLayout absoluteLayout = new AbsoluteLayout ();
+
+                // Create the tick marks (to be sized and positioned later)
+                for (int i = 0; i < tickMarks.Length; i++) {
+                    tickMarks[i] = new BoxView {
+                        Color = Color.Accent
+                    };
+                    absoluteLayout.Children.Add (tickMarks[i]);
+                }
+
+                // Create the three hands.
+                absoluteLayout.Children.Add (hourHand =
+                    new BoxView {
+                        Color = Color.Accent
+                    });
+                absoluteLayout.Children.Add (minuteHand =
+                    new BoxView {
+                        Color = Color.Accent
+                    });
+                absoluteLayout.Children.Add (secondHand =
+                    new BoxView {
+                        Color = Color.Accent
+                    });
+
+                Content = absoluteLayout;
+
+                // Attach a couple event handlers.
+                Device.StartTimer (TimeSpan.FromMilliseconds (16), OnTimerTick);
+                SizeChanged += OnPageSizeChanged;
+            }
+
+            void OnPageSizeChanged (object sender, EventArgs args)
+            {
+                // Size and position the 12 tick marks.
+                Point center = new Point (this.Width / 2, this.Height / 2);
+                double radius = 0.45 * Math.Min (this.Width, this.Height);
+
+                for (int i = 0; i < tickMarks.Length; i++) {
+                    double size = radius / (i % 5 == 0 ? 15 : 30);
+                    double radians = i * 2 * Math.PI / tickMarks.Length;
+                    double x = center.X + radius * Math.Sin (radians) - size / 2;
+                    double y = center.Y - radius * Math.Cos (radians) - size / 2;
+                    AbsoluteLayout.SetLayoutBounds (tickMarks[i], new Rectangle (x, y, size, size));
+
+                    tickMarks[i].AnchorX = 0.51;        // Anchor settings necessary for Android
+                    tickMarks[i].AnchorY = 0.51;
+                    tickMarks[i].Rotation = 180 * radians / Math.PI;
+                }
+
+                // Function for positioning and sizing hands.
+                Action<BoxView, HandParams> Layout = (boxView, handParams) => {
+                    double width = handParams.Width * radius;
+                    double height = handParams.Height * radius;
+                    double offset = handParams.Offset;
+
+                    AbsoluteLayout.SetLayoutBounds (boxView,
+                        new Rectangle (center.X - 0.5 * width,
+                                      center.Y - offset * height,
+                                      width, height));
+
+                    boxView.AnchorX = 0.51;
+                    boxView.AnchorY = handParams.Offset;
+                };
+
+                Layout (secondHand, secondParams);
+                Layout (minuteHand, minuteParams);
+                Layout (hourHand, hourParams);
+            }
+
+            bool OnTimerTick ()
+            {
+                // Set rotation angles for hour and minute hands.
+                DateTime dateTime = DateTime.Now;
+                hourHand.Rotation = 30 * (dateTime.Hour % 12) + 0.5 * dateTime.Minute;
+                minuteHand.Rotation = 6 * dateTime.Minute + 0.1 * dateTime.Second;
+
+                // Do an animation for the second hand.
+                double t = dateTime.Millisecond / 1000.0;
+                if (t < 0.5) {
+                    t = 0.5 * Easing.SpringIn.Ease (t / 0.5);
+                }
+                else {
+                    t = 0.5 * (1 + Easing.SpringOut.Ease ((t - 0.5) / 0.5));
+                }
+                secondHand.Rotation = 6 * (dateTime.Second + t);
+                return true;
+            }
+        }
+    }
+}

Samples/Program.cs

@@ -7,6 +7,8 @@ namespace Samples
     {
         static void Main (string[] args)
         {
+            Xamarin.Forms.Forms.Init ();
+
             for (var i = 0; i < args.Length; i++) {
                 var a = args[i];
                 switch (args[i]) {

Samples/XamarinFormsSample.cs

@@ -10,8 +10,6 @@ namespace Samples
 
 		Page MakePage ()
 		{
-			Forms.Init ();
-
 			var countLabel = new Label {
 				Text = "0",
                 BackgroundColor = Color.Gold,