diff options
Diffstat (limited to 'Xamarin.Forms.Platform.iOS')
| -rw-r--r-- | Xamarin.Forms.Platform.iOS/Platform.cs | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.iOS/Platform.cs b/Xamarin.Forms.Platform.iOS/Platform.cs index b3542d69..5a442bab 100644 --- a/Xamarin.Forms.Platform.iOS/Platform.cs +++ b/Xamarin.Forms.Platform.iOS/Platform.cs @@ -2,6 +2,7 @@ using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; +using CoreGraphics; using Foundation; using UIKit; using RectangleF = CoreGraphics.CGRect; @@ -478,6 +479,30 @@ namespace Xamarin.Forms.Platform.iOS internal class DefaultRenderer : VisualElementRenderer<VisualElement> { + public override UIView HitTest(CGPoint point, UIEvent uievent) + { + // UIview hit testing ignores objects which have an alpha of less than 0.01 + // (see https://developer.apple.com/reference/uikit/uiview/1622469-hittest) + // To prevent layouts with low opacity from being implicitly input transparent, + // we need to temporarily bump their alpha value during the actual hit testing, + // then restore it. If the opacity is high enough or user interaction is disabled, + // we don't have to worry about it. + + nfloat old = Alpha; + if (UserInteractionEnabled && old <= 0.01) + { + Alpha = (nfloat)0.011; + } + + var result = base.HitTest(point, uievent); + + if (UserInteractionEnabled && old <= 0.01) + { + Alpha = old; + } + + return result; + } } } }
\ No newline at end of file |