fix: Fix possible scroll to out of bounds of the SV on iOS

unoplatform · Jun 2, 2021 · d1f0296 · d1f0296
1 parent ba767c5
commit d1f0296
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Showing 2 changed files with 10 additions and 7 deletions.
diff --git a/src/Uno.UI/UI/Xaml/Controls/ScrollViewer/ScrollViewer.iOS.cs b/src/Uno.UI/UI/Xaml/Controls/ScrollViewer/ScrollViewer.iOS.cs
@@ -85,10 +85,17 @@ private bool ChangeViewNative(double? horizontalOffset, double? verticalOffset,
 				var success = desiredOffsets == clampedOffsets;
 				if (!success && IsArrangeDirty)
 				{
+					// If the the requested offsets are out-of - bounds, but we actually does have our final bounds yet,
+					// we allow to set the desired offsets. If needed, they will then be clamped by the OnAfterArrange().
+					// This is needed to allow a ScrollTo before the SV has been layouted.
+
 					_pendingChangeView = (horizontalOffset, verticalOffset, disableAnimation);
+					_scrollableContainer.SetContentOffset(desiredOffsets, !disableAnimation);
+				}
+				else
+				{
+					_scrollableContainer.SetContentOffset(clampedOffsets, !disableAnimation);
 				}
-
-				_scrollableContainer.SetContentOffset(desiredOffsets, !disableAnimation);
 
 				if(zoomFactor is { } zoom)
 				{

diff --git a/src/Uno.UI/UI/Xaml/UIElement.debugging.cs b/src/Uno.UI/UI/Xaml/UIElement.debugging.cs
@@ -24,17 +24,13 @@
 using Windows.UI.Core;
 using System.Text;
 
-#if __IOS__
-using UIKit;
-#endif
-
 #if XAMARIN_ANDROID
 using View = Android.Views.View;
 using ViewGroup = Android.Views.ViewGroup;
 using Font = Android.Graphics.Typeface;
 using Android.Graphics;
 using DependencyObject = System.Object;
-#elif XAMARIN_IOS
+#elif __IOS__
 using View = UIKit.UIView;
 using ViewGroup = UIKit.UIView;
 using UIKit;