Update UIViewRepresentable size from UIKit in SwiftUI

Question

I\'m embedding a view controller with variable-height UITextView inside a parent SwiftUI VStack and the view controller sizes it\'s frame to the whole screen be

Answer 1

Without being able to see more of your code, it's slightly difficult to say what the best solution would be, but based purely on this part of your question...

I can get the correct size of the UITextView in didLayoutSubviews and pass it upwards to SwiftUI where it can be set properly - but where do I do that?

I would suggest that you pass a binding property to your view controller that can be set to the calculated text view height, meaning that the view that contains your VStack would have a @State property like this:

@State private var textViewHeight: CGFloat = 0

You would then declare a @Binding property on your HighlighterVC and add an initializer like this:

@Binding var textViewHeight: CGFloat

init(textViewHeight: Binding) {
    self._textViewHeight = textViewHeight
}

And then you would set textViewHeight to the calculated height in your didLayoutSubviews and add a .frame modifier to your HighlighterVC like this:

VStack {
    HighlighterVC(textViewHeight: self.$textViewHeight)
        .frame(height: self.textViewHeight)
    Text("Tap and drag to highlight")
        .foregroundColor(.gray)
        .font(.caption)
}

Like I said at the beginning of my answer, this solution (that I believe would work, but since I can't test it, I'm not 100% certain) is based on your thoughts about what it is that you need. Without seeing more code, it's impossible for me to say if this is the best solution.