UIKit:如何在缩放图像的顶部添加UITextfield

试图在缩放图像的顶部添加UITextfield。我可以捏一下放大图像,但添加UITextField是我遇到的问题。我试图让UITextField在放大/缩小图像时停留在图像的特定部分。我以为我已经接近了,但Xcode似乎不喜欢我添加到UITextfield的约束。谢谢你的帮助。

当前代码:

import UIKit
import Foundation

class ZoomImage: UIViewController, UITextFieldDelegate {
    
    private var textField: UITextField {
        let ut = UITextField()
        ut.backgroundColor = .black
        return ut
    }
    
    // create scrollView
    private let scrollView: UIScrollView = {
        let sv = UIScrollView()
        sv.backgroundColor = .red
        return sv
    }()
    
    // create imageView
    private var imageView: UIImageView = {
        let v = UIImageView()
        v.backgroundColor = .blue
        return v
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setup()
    }
    
    func setup() {
        // Allows us to have this view be the delegate of the textfield
        self.textField.delegate = self
        // Allows us to have this view be the delegate of the scrollview
        scrollView.delegate = self
        // add Scrollview to view
        self.view.addSubview(scrollView)
        
        // Defining imageView
        let image = UIImage(named: "test.png")!
        imageView = UIImageView(image: image)
        imageView.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: image.preferredPresentationSizeForItemProvider)
        imageView.contentMode = .scaleAspectFit
        imageView.addSubview(textField)
        
        //Defining Textfield
        textField.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: image.preferredPresentationSizeForItemProvider)
        textField.placeholder = "TEsting"
        
        // add UIImageView to scroll view
        scrollView.addSubview(imageView)
        scrollView.addSubview(textField)
        
        imageView.translatesAutoresizingMaskIntoConstraints = false
        textField.translatesAutoresizingMaskIntoConstraints = false
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        
        // respect safe-area
        let safeG = view.safeAreaLayoutGuide
        
        // Zoom range
        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 10.0
        
        // constraints
        NSLayoutConstraint.activate([
            scrollView.leadingAnchor.constraint(equalTo: safeG.leadingAnchor, constant: 0),
            scrollView.trailingAnchor.constraint(equalTo: safeG.trailingAnchor, constant: 0),
            scrollView.bottomAnchor.constraint(equalTo: safeG.bottomAnchor, constant: 0),
            scrollView.topAnchor.constraint(equalTo: safeG.topAnchor, constant: 0),
            
            imageView.leadingAnchor.constraint(equalTo: self.scrollView.leadingAnchor, constant: 0),
            imageView.trailingAnchor.constraint(equalTo: self.scrollView.trailingAnchor, constant: 0),
            imageView.bottomAnchor.constraint(equalTo: self.scrollView.bottomAnchor, constant: 0),
            imageView.topAnchor.constraint(equalTo: self.scrollView.topAnchor, constant: 0),
            
            imageView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
            imageView.heightAnchor.constraint(equalTo: scrollView.heightAnchor),
            
            textField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 0),
            textField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: 0),
            textField.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: 0),
            textField.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0)
            
        ])
    }
}

extension ZoomImage:  UIScrollViewDelegate {
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }
}