Hello. Recently, while studying alignmentGuide, I had questions about it behaving differently from the documentation when setting multiple alignment guides.
For example, the document states that only the alignmentGuide modifier with a first parameter matching the container's alignment will function.
Therefore, I thought that writing the Swift code below would result in the yellow color's center alignment being aligned with the HStack's bottom alignment.
struct TestView: View {
var body: some View {
HStack(alignment: .bottom) {
Color.yellow
.frame(height: 50)
.alignmentGuide(VerticalAlignment.center) { dim in
dim[.top]
}
.alignmentGuide(VerticalAlignment.top) { dim in
dim[.bottom]
}
.alignmentGuide(VerticalAlignment.bottom) { dim in
dim[VerticalAlignment.center]
}
Text("Hello, world")
}
.border(.green)
}
}
Expect
However, in reality, I observed that the top of the yellow color aligns with the HStack's bottom alignment. From this, I inferred that the 3rd alignmentGuide is applied first, and this also causes the first alignmentGuide to work, which makes me curious about how this is possible. If I leave only the 3rd alignmentGuide, it behaves as I expected.
Real Behavior
Could anybody help me to figure it out this behavior? Thank you
HoJongE
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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.