feat: Naive implementation of UIElement.UpdateLayout

unoplatform · Nov 16, 2020 · af4370f · af4370f
1 parent 9b19af3
commit af4370f
Show file tree

Hide file tree

Showing 2 changed files with 47 additions and 1 deletion.
diff --git a/src/Uno.UI/Generated/3.0.0.0/Windows.UI.Xaml/UIElement.cs b/src/Uno.UI/Generated/3.0.0.0/Windows.UI.Xaml/UIElement.cs
@@ -1156,7 +1156,7 @@ public  void InvalidateArrange()
 			global::Windows.Foundation.Metadata.ApiInformation.TryRaiseNotImplemented("Windows.UI.Xaml.UIElement", "void UIElement.InvalidateArrange()");
 		}
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public  void UpdateLayout()
 		{

diff --git a/src/Uno.UI/UI/Xaml/UIElement.cs b/src/Uno.UI/UI/Xaml/UIElement.cs
@@ -329,6 +329,52 @@ private void OpenContextFlyout(object sender, RightTappedRoutedEventArgs args)
 
 		internal bool IsRenderingSuspended { get; set; }
 
+		[ThreadStatic]
+		private static bool _isInUpdateLayout;
+
+		private const int MaxLayoutIterations = 250;
+
+		public void UpdateLayout()
+		{
+			if (_isInUpdateLayout)
+			{
+				return;
+			}
+
+			var root = Window.Current.RootElement;
+			if (root is null)
+			{
+				return;
+			}
+
+			try
+			{
+				_isInUpdateLayout = true;
+
+				for (var i = 0; i < MaxLayoutIterations; i++)
+				{
+					if (root.IsMeasureDirty)
+					{
+						root.Measure(LayoutInformation.GetLayoutSlot(root).Size);
+					}
+					else if (root.IsArrangeDirty)
+					{
+						root.Arrange(LayoutInformation.GetLayoutSlot(root));
+					}
+					else
+					{
+						return;
+					}
+				}
+
+				throw new InvalidOperationException("Layout cycle detected.");
+			}
+			finally
+			{
+				_isInUpdateLayout = false;
+			}
+		}
+
 		internal void ApplyClip()
 		{
 			Rect rect;