BottomSheetWithDetentsSwiftUI.swift

import UIKit
import SwiftUI

// Hacky workaround, use at your own risk and all that
struct BottomSheetPresenter<Content>: UIViewRepresentable where Content: View{
    let label: String
    let content: Content
    let detents: [UISheetPresentationController.Detent]
    
    init(_ label: String, detents: [UISheetPresentationController.Detent], @ViewBuilder content: () -> Content) {
        self.label = label
        self.content = content()
        self.detents = detents
    }
    
    func makeUIView(context: UIViewRepresentableContext<BottomSheetPresenter>) -> UIButton {
        let button = UIButton(type: .system)
        button.setTitle(label, for: .normal)
        button.addAction(UIAction { _ in
            let hostingController = UIHostingController(rootView: content)
            let viewController = UIBottomSheetWrapper(detents: detents)

            viewController.addChild(hostingController)
            viewController.view.addSubview(hostingController.view)
            hostingController.view.pinToEdgesOf(viewController.view)
            hostingController.didMove(toParent: viewController)
            
            button.window?.rootViewController?.present(viewController, animated: true)
        }, for: .touchUpInside)
        
        print("make...")
        
        return button
    }
    
    func updateUIView(_ uiView: UIButton, context: Context) {
        // no updates
    }
    
    func makeCoordinator() -> Void {
        return ()
    }
}

extension BottomSheetPresenter {
    class UIBottomSheetWrapper: UIViewController {
        let detents: [UISheetPresentationController.Detent]
        
        init(detents: [UISheetPresentationController.Detent]) {
            self.detents = detents
            super.init(nibName: nil, bundle: nil)
        }
        
        required init?(coder: NSCoder) {
            fatalError("No Storyboards")
        }
        
        override func viewDidLoad() {
            super.viewDidLoad()
            
            view.backgroundColor = .gray
            
            if let sheetController = self.presentationController as? UISheetPresentationController {
                sheetController.detents = detents
            }
        }
    }
}

extension UIView {
    func pinToEdgesOf(_ other: UIView) {
        translatesAutoresizingMaskIntoConstraints = false
        
        leftAnchor.constraint(equalTo: other.leftAnchor).isActive = true
        topAnchor.constraint(equalTo: other.topAnchor).isActive = true
        rightAnchor.constraint(equalTo: other.rightAnchor).isActive = true
        bottomAnchor.constraint(equalTo: other.bottomAnchor).isActive = true
    }
}

// Usage
struct ContentView: View {
    var body: some View {
        VStack {
            BottomSheetPresenter("Tap me for a bottom sheet!!", detents: [.medium(), .large()]) {
                VStack {
                    Text("This is a test")

                    Rectangle()
                        .frame(width: 300, height: 300, alignment: .leading)
                        .foregroundColor(.blue)
                }
            }
        }
    }
}

UIApplication.shared.windows.first?.rootViewController?.present wouldn't work as intended for apps with multiple scenes, button.window?.rootViewController?.present should work better (the button's window will be set at the time the button is tapped)
That's the only "hacky" thing I see here, the rest looks good to me!

Thanks! 😁 I'll modify the gist to use your suggestion