[Windows] Fix PlatformTicker.Windows.cs — IsRunning always returns false

src/Core/src/Animations/PlatformTicker.Windows.cs

@@ -5,15 +5,32 @@ namespace Microsoft.Maui.Animations
 	/// <inheritdoc/>
 	public class PlatformTicker : Ticker
 	{
+		bool _isRunning;
+
+		/// <inheritdoc/>
+		public override bool IsRunning => _isRunning;
+
 		/// <inheritdoc/>
 		public override void Start()
 		{
+			if (_isRunning)
+			{
+				return;
+			}
+
+			_isRunning = true;
 			CompositionTarget.Rendering += RenderingFrameEventHandler;
 		}
 
 		/// <inheritdoc/>
 		public override void Stop()
 		{
+			if (!_isRunning)
+			{
+				return;
+			}
+
+			_isRunning = false;
 			CompositionTarget.Rendering -= RenderingFrameEventHandler;
 		}
 

src/Core/src/PublicAPI/net-windows/PublicAPI.Unshipped.txt

@@ -1,4 +1,5 @@
 #nullable enable
+override Microsoft.Maui.Animations.PlatformTicker.IsRunning.get -> bool
 override Microsoft.Maui.Platform.LayoutPanel.OnCreateAutomationPeer() -> Microsoft.UI.Xaml.Automation.Peers.AutomationPeer!
 override Microsoft.Maui.Platform.MauiPasswordTextBox.OnCreateAutomationPeer() -> Microsoft.UI.Xaml.Automation.Peers.AutomationPeer!
 override Microsoft.Maui.Platform.ContentPanel.MeasureOverride(Windows.Foundation.Size availableSize) -> Windows.Foundation.Size

src/Core/tests/DeviceTests/Animations/PlatformTickerTests.Windows.cs

@@ -0,0 +1,73 @@
+using System.Threading.Tasks;
+using Microsoft.Maui.Animations;
+using Xunit;
+
+namespace Microsoft.Maui.DeviceTests
+{
+	[Category(TestCategory.Animation)]
+	public class PlatformTickerTests : TestBase
+	{
+		[Fact]
+		public async Task IsRunning_ReflectsStartAndStop()
+		{
+			await InvokeOnMainThreadAsync(() =>
+			{
+				var ticker = new PlatformTicker();
+
+				Assert.False(ticker.IsRunning, "Should be false before Start");
+
+				ticker.Start();
+				Assert.True(ticker.IsRunning, "Should be true after Start");
+
+				ticker.Stop();
+				Assert.False(ticker.IsRunning, "Should be false after Stop");
+			});
+		}
+
+		[Fact]
+		public async Task Start_IsIdempotent_NoDuplicateSubscriptions()
+		{
+			await InvokeOnMainThreadAsync(async () =>
+			{
+				var ticker = new PlatformTicker();
+				int fireCount = 0;
+				ticker.Fire = () => fireCount++;
+
+				ticker.Start();
+				ticker.Start(); // second call should be a no-op
+				ticker.Start(); // third call should be a no-op
+
+				// Yield a few composition frames
+				await Task.Delay(100);
+
+				ticker.Stop();
+				var firesAfterStop = fireCount;
+
+				await Task.Delay(50);
+
+				// No additional fires after Stop
+				Assert.Equal(firesAfterStop, fireCount);
+				// ~6 expected at 60Hz over 100ms; 3x subscriptions would yield ~18+
+				Assert.InRange(firesAfterStop, 1, 20);
+			});
+		}
+
+		[Fact]
+		public async Task AnimationManager_StartsTickerOnce_AcrossMultipleAdds()
+		{
+			await InvokeOnMainThreadAsync(() =>
+			{
+				var ticker = new PlatformTicker();
+				var manager = new AnimationManager(ticker);
+
+				for (int i = 0; i < 5; i++)
+					manager.Add(new Animation { Duration = 1.0 });
+
+				Assert.True(ticker.IsRunning);
+
+				ticker.Stop();
+				Assert.False(ticker.IsRunning);
+			});
+		}
+	}
+}

src/Core/tests/DeviceTests/TestCategory.cs

@@ -51,5 +51,6 @@ public static class TestCategory
 		public const string View = "View";
 		public const string WebView = "WebView";
 		public const string Window = "Window";
+		public const string Animation = "Animation";
 	}
 }