Is there any plans to isolate alignmentGuide's computeValue closure?

Question

Created Dec ’24

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Hello. I am developing an application using Swift 6 and SwiftUI.

I have custom implemented a BottomSheet that animates from bottom to top, and I attempted to achieve this animation by changing the alignmentGuide like this.

ZStack(alignment: .bottom) {
    dimView
        .opacity(isVisible ? 1 : 0)
        .transaction { transaction in
            transaction.animation = .easeInOut(duration: 0.35)
        }
    bottomSheetView
        .alignmentGuide(VerticalAlignment.bottom) { dimension in
            // compile error occur because isVisible property is state of MainActor isolated View!
            isVisible ? dimension[.bottom] : dimension[.top]
        }
}

There were no issues in Swift 5, but now I am encountering compile errors because the computeValue closure of the alignmentGuide is not isolated to the MainActor, preventing me from calling view state values or functions.

So I am curious if there are any plans to isolate this closure to the MainActor. From my observation, this closure is always called on the main thread.

Thank you.

Boost

Answer 1

Fat Xu OP

Dec ’24

Accepted Answer

ZStack(alignment: .bottom) {
.....   
let isVisible = isVisible // Remove isolation

    bottomSheetView
        .alignmentGuide(VerticalAlignment.bottom) { dimension in
            isVisible ? dimension[.bottom] : dimension[.top]
        }
}

or

 .alignmentGuide(VerticalAlignment.bottom) { dimension in
          
            _isVisible.wrappedValue ? dimension[.bottom] : dimension[.top]
        }

2