FB19760681: TextField with axis: .vertical has invalid intrinsicContentSize

[malhal]

Submission Date

2025-08-19

Status

Open

Area

SwiftUI

Operating System Version

iOS 26

Type

Incorrect/Unexpected Behavior

Description

Hi I noticed when I use axis .vertical the intrinsicContentSize is invalid, it's 0,0. I know this renders as a UITextView in this case instead of a UITextField when its single line so probably has something to do with that. e.g.

@State var text = "Test"

TextField("", text: $text, axis: .vertical) 

Incorrectly gives:

intrinsicContentSize (0.0, 0.0)
preferredContentSize (0.0, 0.0)

TextField(text: $text)

Correctly gives:

intrinsicContentSize (32.666666666666664, 22.0)
preferredContentSize (32.666666666666664, 22.0)

I've attached my test harness that uses a UIHostingController in a UIViewControllerRepresentable to read the sizes. Run it on iPhone 16 Simulator in Xcode 26 beta 6. Or current release Xcode with iOS 18.

I discovered it because I'm working on a UIViewController container view for SwiftUI content in a SwiftUI hierarchy.

import SwiftUI


struct ExpandingView: View {

    @State var text = "Test"
    var body: some View {

        TextField("", text: $text, axis: .vertical) // intrinsicContentSize is bad
        //TextField(text: $text)
    }
}



struct WrapperHostingControllerRepresentable<Content: View>: UIViewControllerRepresentable {
    @ViewBuilder var content: Content
    
    func makeUIViewController(context: Context) -> MyHostingController<Content> {
        let vc = MyHostingController(rootView: content)
        vc.safeAreaRegions = []
        vc.sizingOptions = [.preferredContentSize]
       return vc
    }
    
    func updateUIViewController(_ uiViewController: MyHostingController<Content>, context: Context) {
        uiViewController.rootView = content
    }
    
    func sizeThatFits(_ proposal: ProposedViewSize, uiViewController: MyHostingController<Content>, context: Context) -> CGSize? {
        print("representable sizeThatFits")
        let target = CGSize(
            width: proposal.width ?? 0,
            height: proposal.height ?? 0
        )

       var size = uiViewController.sizeThatFits(in: target)
        print("sizeThatFits \(size)")
        return size
    }
}


class MyHostingController<Content: View>: UIHostingController<Content> {
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        
        print("intrinsicContentSize \(view.intrinsicContentSize)")
        print("preferredContentSize \(preferredContentSize)")
        
    }
    
}

struct ContentView: View {
    var body: some View {
        WrapperHostingControllerRepresentable {
            ExpandingView()
        }
        .border(Color.red)
    }
}

Keywords

No response

Prerequisites

• [x] The title follows the format FB<number>: <title>
• [x] I will keep this issue updated with Apple's responses