Attach a view to the keyboard with interactive dismissal support

KeyboardAttachedView.swift

//
//  ContentView.Swift
//  KeyboardAttachedView
//
//  Created by Gavin Nelson on 8/19/24.
//

import SwiftUI
import UIKit

struct ContentView: View {
	var body: some View {
		ZStack(alignment: .bottom) {
			VStack {
				ScrollView {
					ForEach(0..<20) { index in
						HStack {
							Text("Item \(index + 1)")
								.padding()
							Spacer()
						}
					}
				}
				.scrollDismissesKeyboard(.interactively)
				.scrollClipDisabled()
				KeyboardAttachedView()
					.frame(height: 44)
			}
		}
		.ignoresSafeArea(.keyboard)
	}
}

struct TextInputView: View {
	@State private var textFieldText = ""
	var body: some View {
		TextField("Type here", text: $textFieldText)
			.textFieldStyle(RoundedBorderTextFieldStyle())
			.padding()
	}
}

struct KeyboardAttachedView: UIViewControllerRepresentable {
	func makeUIViewController(context: Context) -> KeyboardObservingViewController {
		return KeyboardObservingViewController()
	}
	func updateUIViewController(_ uiViewController: KeyboardObservingViewController, context: Context) {}
}

class KeyboardObservingViewController: UIViewController {
	private var bottomConstraint: NSLayoutConstraint?
	
	override func viewDidAppear(_ animated: Bool) {
		super.viewDidAppear(animated)
		
		let textView = TextInputView()
		let hostView = UIHostingController(rootView: textView)
		
		hostView.view.translatesAutoresizingMaskIntoConstraints = false
		hostView.view.backgroundColor = .clear
		view.addSubview(hostView.view)
		
		NSLayoutConstraint.activate([
			hostView.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
			hostView.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
			hostView.view.heightAnchor.constraint(equalToConstant: 44)
		])
		
		bottomConstraint = hostView.view.bottomAnchor.constraint(equalTo: view.keyboardLayoutGuide.topAnchor)
		bottomConstraint?.isActive = true
		
		view.keyboardLayoutGuide.topAnchor.constraint(equalTo: hostView.view.bottomAnchor).isActive = true
	}
	
	override func viewDidDisappear(_ animated: Bool) {
		super.viewDidDisappear(animated)
	}
}