SwiftUI ignores UIView.isUserInteractionEnabled and other UIKit hit-testing methods

Originator:matt.curtis.biz
Number:rdar://FB9818366 Date Originated:12/22/2021
Status:Open Resolved:
Product:SwiftUI Product Version:15.4
Classification: Reproducible:
 
Problem:

SwiftUI doesn't respect the hit-testing preferences of the UIViews inside UIViewRepresentables.

Twitter thread of me complaining about this problem: https://twitter.com/mattxcurtis/status/1473543903232118787

UIViews have several ways they can react to hit-testing, primarily:

- UIView.isUserInteractionEnabled
- UIView.point(inside:event:)
- UIView.hitTest(_:event:)

While UIViewRepresentable will let you embed a UIView in SwiftUI content, SwiftUI completely ignores the inner UIView's hit-testing preferences, and instead treats the entire region of space the UIViewRepresentable takes up as a fully hit-testable area, which means the UIViewRepresentable blocks all touches to any SwiftUI content below it.

Steps to reproduce:

The attached project demonstrates this issue with a UIViewRepresentable that creates a UIView that has isUserInteractionEnabled set to false. The UIViewRepresentable still blocks touches to the SwiftUI content below it.

Link to the project attached to the original radar on Github: https://github.com/matt-curtis/UIViewRepresentable-hitTest-bug-demonstration

Expected behavior:

SwiftUI should be take into account and respect the hit-testing preferences of the UIView content it lets you embed. Not taking this hit-testing into account makes it much harder to integrate UIKit content with SwiftUI content.

Workarounds:

Using SwiftUI's contentShape, or allowsHitTesting, can give you some ability to mitigate this problem, but they are no substitute for the flexibility of UIKit's built-in methods.

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