Automatically marshal all AnimationExtensions calls onto UI thread (#48)

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla39821.cs

@@ -0,0 +1,118 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Threading.Tasks;
+using Xamarin.Forms.CustomAttributes;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 39821, "ViewExtension.TranslateTo cannot be invoked on Main thread")]
+	public class Bugzilla39821 : TestContentPage 
+	{
+		protected override void Init()
+		{
+			var box = new BoxView { BackgroundColor = Color.Blue, WidthRequest = 50, HeightRequest = 50, HorizontalOptions = LayoutOptions.Center };
+
+			var instructions = new Label { Text = "Click the 'Animate' button to run animation on the box. If the animations complete without crashing, this test has passed." };
+
+			var success = new Label { Text = "Success", IsVisible = false };
+
+			var button = new Button() { Text = "Animate" };
+
+			Content = new StackLayout
+			{
+				VerticalOptions = LayoutOptions.Fill,
+				HorizontalOptions = LayoutOptions.Fill,
+				Children =
+				{
+					instructions,
+					success,
+					button,
+					new AbsoluteLayout
+					{
+						Children = { box },
+						HorizontalOptions = LayoutOptions.Fill,
+						VerticalOptions = LayoutOptions.Fill
+					}
+				}
+			};
+
+			button.Clicked += async (sender, args) => {
+				// Run a bunch of animations from the thread pool 
+				await Task.WhenAll(
+					Task.Run(async () => await Translate(box)),
+					Task.Run(async () => await CheckTranslateRunning(box)),
+					Task.Run(async () => await AnimateScale(box)),
+					Task.Run(async () => await Rotate(box)),
+					Task.Run(async () => await Animate(box)),
+					Task.Run(async () => await Kinetic(box)),
+					Task.Run(async () => await Cancel(box))
+					);
+
+				success.IsVisible = true;
+			};
+		}
+
+		async Task CheckTranslateRunning(BoxView box)
+		{
+			Debug.WriteLine(box.AnimationIsRunning("TranslateTo") ? "Translate is running" : "Translate is not running");
+		}
+
+		static async Task Translate(BoxView box)
+		{
+			var currentX = box.X;
+			var currentY = box.Y;
+
+			await box.TranslateTo(currentX, currentY + 100);
+			await box.TranslateTo(currentX, currentY);
+		}
+
+		static async Task AnimateScale(BoxView box)
+		{
+			await box.ScaleTo(2);
+			await box.ScaleTo(0.5);
+		}
+
+		static async Task Rotate(BoxView box)
+		{
+			await box.RelRotateTo(360);
+		}
+
+		async Task Cancel(BoxView box)
+		{
+			box.AbortAnimation("animate");
+			box.AbortAnimation("kinetic");
+		}
+
+		async Task Animate(BoxView box)
+		{
+			box.Animate("animate", d => d, d => { }, 100, 1);
+		}
+
+		async Task Kinetic(BoxView box)
+		{
+			var resultList = new List<Tuple<double, double>>();
+
+			box.AnimateKinetic("kinetic", (distance, velocity) =>
+			{
+				resultList.Add(new Tuple<double, double>(distance, velocity));
+				return true;
+			}, 100, 1);
+		}
+
+#if UITEST
+		[Test]
+		public void DoesNotCrash()
+		{
+			RunningApp.Tap(q => q.Marked("Animate"));
+			RunningApp.WaitForElement(q => q.Marked("Success"));
+		}
+#endif
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -91,6 +91,7 @@
     </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39702.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40173.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39821.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34727.cs" />

Xamarin.Forms.Controls/App.cs

@@ -3,6 +3,7 @@
 using System.IO;
 using System.Reflection;
 using System.Threading.Tasks;
+using Xamarin.Forms.Controls.Issues;
 
 namespace Xamarin.Forms.Controls
 {
@@ -23,8 +24,9 @@ public App()
 		{
 			_testCloudService = DependencyService.Get<ITestCloudService>();
 			InitInsights();
-			// MainPage = new MainPageLifeCycleTests ();
-			MainPage = new MasterDetailPage {
+			//MainPage = new MainPageLifeCycleTests();
+			MainPage = new MasterDetailPage
+			{
 				Master = new ContentPage { Title = "Master", BackgroundColor = Color.Red },
 				Detail = CoreGallery.GetMainPage()
 			};

Xamarin.Forms.Core/AnimationExtensions.cs

@@ -42,11 +42,29 @@ static AnimationExtensions()
 
 		public static bool AbortAnimation(this IAnimatable self, string handle)
 		{
-			CheckAccess();
-
 			var key = new AnimatableKey(self, handle);
 
-			return AbortAnimation(key) && AbortKinetic(key);
+			if (!s_animations.ContainsKey(key) && !s_kinetics.ContainsKey(key))
+			{
+				return false;
+			}
+
+			Action abort = () =>
+			{
+				AbortAnimation(key);
+				AbortKinetic(key);
+			};
+
+			if (Device.IsInvokeRequired)
+			{
+				Device.BeginInvokeOnMainThread(abort);
+			}
+			else
+			{
+				abort();
+			}
+
+			return true;
 		}
 
 		public static void Animate(this IAnimatable self, string name, Animation animation, uint rate = 16, uint length = 250, Easing easing = null, Action<double, bool> finished = null,
@@ -67,8 +85,9 @@ public static bool AbortAnimation(this IAnimatable self, string handle)
 			self.Animate(name, x => x, callback, rate, length, easing, finished, repeat);
 		}
 
-		public static void Animate<T>(this IAnimatable self, string name, Func<double, T> transform, Action<T> callback, uint rate = 16, uint length = 250, Easing easing = null,
-									  Action<T, bool> finished = null, Func<bool> repeat = null)
+		public static void Animate<T>(this IAnimatable self, string name, Func<double, T> transform, Action<T> callback,
+			uint rate = 16, uint length = 250, Easing easing = null,
+			Action<T, bool> finished = null, Func<bool> repeat = null)
 		{
 			if (transform == null)
 				throw new ArgumentNullException(nameof(transform));
@@ -77,8 +96,75 @@ public static bool AbortAnimation(this IAnimatable self, string handle)
 			if (self == null)
 				throw new ArgumentNullException(nameof(self));
 
-			CheckAccess();
+			Action animate = () => AnimateInternal(self, name, transform, callback, rate, length, easing, finished, repeat);
+
+			if (Device.IsInvokeRequired)
+			{
+				Device.BeginInvokeOnMainThread(animate);
+			}
+			else
+			{
+				animate();
+			}
+		}
+
+
+		public static void AnimateKinetic(this IAnimatable self, string name, Func<double, double, bool> callback, double velocity, double drag, Action finished = null)
+		{
+			Action animate = () => AnimateKineticInternal(self, name, callback, velocity, drag, finished);
+
+			if (Device.IsInvokeRequired)
+			{
+				Device.BeginInvokeOnMainThread(animate);
+			}
+			else
+			{
+				animate();
+			}
+		}
+
+		public static bool AnimationIsRunning(this IAnimatable self, string handle)
+		{
+			var key = new AnimatableKey(self, handle);
+			return s_animations.ContainsKey(key);
+		}
+
+		public static Func<double, double> Interpolate(double start, double end = 1.0f, double reverseVal = 0.0f, bool reverse = false)
+		{
+			double target = reverse ? reverseVal : end;
+			return x => start + (target - start) * x;
+		}
+
+		static void AbortAnimation(AnimatableKey key)
+		{
+			if (!s_animations.ContainsKey(key))
+			{
+				return;
+			}
+
+			Info info = s_animations[key];
+			info.Tweener.ValueUpdated -= HandleTweenerUpdated;
+			info.Tweener.Finished -= HandleTweenerFinished;
+			info.Tweener.Stop();
+			info.Finished?.Invoke(1.0f, true);
+
+			s_animations.Remove(key);
+		}
 
+		static void AbortKinetic(AnimatableKey key)
+		{
+			if (!s_kinetics.ContainsKey(key))
+			{
+				return;
+			}
+
+			Ticker.Default.Remove(s_kinetics[key]);
+			s_kinetics.Remove(key);
+		}
+
+		static void AnimateInternal<T>(IAnimatable self, string name, Func<double, T> transform, Action<T> callback,
+			uint rate, uint length, Easing easing, Action<T, bool> finished, Func<bool> repeat)
+		{
 			var key = new AnimatableKey(self, name);
 
 			AbortAnimation(key);
@@ -107,19 +193,16 @@ public static bool AbortAnimation(this IAnimatable self, string handle)
 			tweener.Start();
 		}
 
-		public static void AnimateKinetic(this IAnimatable self, string name, Func<double, double, bool> callback, double velocity, double drag, Action finished = null)
+		static void AnimateKineticInternal(IAnimatable self, string name, Func<double, double, bool> callback, double velocity, double drag, Action finished = null)
 		{
-			CheckAccess();
-
 			var key = new AnimatableKey(self, name);
 
 			AbortKinetic(key);
 
 			double sign = velocity / Math.Abs(velocity);
 			velocity = Math.Abs(velocity);
 
-			int tick = Ticker.Default.Insert(step =>
-			{
+			int tick = Ticker.Default.Insert(step => {
 				long ms = step;
 
 				velocity -= drag * ms;
@@ -142,56 +225,6 @@ public static void AnimateKinetic(this IAnimatable self, string name, Func<doubl
 			s_kinetics[key] = tick;
 		}
 
-		public static bool AnimationIsRunning(this IAnimatable self, string handle)
-		{
-			CheckAccess();
-
-			var key = new AnimatableKey(self, handle);
-
-			return s_animations.ContainsKey(key);
-		}
-
-		public static Func<double, double> Interpolate(double start, double end = 1.0f, double reverseVal = 0.0f, bool reverse = false)
-		{
-			double target = reverse ? reverseVal : end;
-			return x => start + (target - start) * x;
-		}
-
-		static bool AbortAnimation(AnimatableKey key)
-		{
-			if (!s_animations.ContainsKey(key))
-			{
-				return false;
-			}
-
-			Info info = s_animations[key];
-			info.Tweener.ValueUpdated -= HandleTweenerUpdated;
-			info.Tweener.Finished -= HandleTweenerFinished;
-			info.Tweener.Stop();
-			info.Finished?.Invoke(1.0f, true);
-
-			return s_animations.Remove(key);
-		}
-
-		static bool AbortKinetic(AnimatableKey key)
-		{
-			if (!s_kinetics.ContainsKey(key))
-			{
-				return false;
-			}
-
-			Ticker.Default.Remove(s_kinetics[key]);
-			return s_kinetics.Remove(key);
-		}
-
-		static void CheckAccess()
-		{
-			if (Device.IsInvokeRequired)
-			{
-				throw new InvalidOperationException("Animation operations must be invoked on the UI thread");
-			}
-		}
-
 		static void HandleTweenerFinished(object o, EventArgs args)
 		{
 			var tweener = o as Tweener;