Maybe one for <#CTJB58X7X|>, but I encountered a u...

# ios

[darkmoon_uk]

Maybe one for #CTJB58X7X, but I encountered a use case that I don't think is yet well catered for by SKIE Flow/SwiftUI interop.

Say you're transitioning a native iOS App to Kotlin Multiplatform and during the migration you need to create a bi-directional binding between a SwiftUI Binding<> and a Kotlin MutableStateFlow,
for example, swift:

someView
    .sheet(isPresented: isShowLoginSheet) { // <-- Super common usage of bottom sheet in SwiftUI
        ...

...sheet takes a Binding<Bool> that opens a bottom sheet when it becomes true.
In the other direction; SwiftUI writes false into this binding, when the sheet is dismissed.

Now, if you want to fully bind that to a MutableStateFlow, you'd need some code to detect the Binding change and set it back to the flow's .value.

I set out to make a FlowBinding utility to achieve this.
Due to synchronisation issues, it wasn't as straightforward as anticipated, so I ended up with the code in thread.
This works but I think it can probably be improved - code in 🧵 in case this problem piques any interests!

[darkmoon_uk]

FlowBinding.cpp

FlowBinding.cpp

[darkmoon_uk]

Usage:

var body: some View {
        return FlowBinding(
            mutableStateFlow: globalState.isShowLoginSheet, // <-- Don't hurt me, this part is inherited
            transformOut: { kotlinBool in kotlinBool.boolValue },
            transformIn: { bool in bool.asKotlin() }
        ) { (isShowLoginSheetKotlinBinding: Binding<Bool>) in
            ...

[François]

Hi, I have thought about that issue after writer my macro who manage only unidirectional binding with kotlin type.
To add the bidirectional, I need to rewrite my macro declaration.
Thanks to remember me to think about it.

[François]

The swift macro way could reduce the boilerplate of creating a bidirectional binding.

[François]

I just add the features, yeah 😄
---
About you’re context, Yeah, it seems too much complex.
Currently, there is no (never?) guideline about how to really use KMP on iOS.
So, I think you should stick to what you can do and avoid overthinking this. 😄