如何在Swift中模拟safari的搜索栏UI/动画？

import UIKit

class SearchBarView: UIView, UITextFieldDelegate {
    private let searchBar: UITextField
    
    override init(frame: CGRect) {
        searchBar = UITextField(frame: CGRect(x: 10, y: 10, width: frame.width - 20, height: frame.height - 20))
        searchBar.borderStyle = .roundedRect
        searchBar.backgroundColor = .white
        searchBar.font = UIFont.systemFont(ofSize: 14)
        searchBar.delegate = self
        
        super.init(frame: frame)
        
        addSubview(searchBar)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func animateSearchBar(expanded: Bool) {
        let targetFrame = expanded ? CGRect(x: 10, y: 10, width: frame.width - 20, height: frame.height - 20) : CGRect(x: 10, y: 10, width: 100, height: frame.height - 20)
        
        UIView.animate(withDuration: 0.3) {
            self.searchBar.frame = targetFrame
        }
    }
    
    // MARK: - UITextFieldDelegate
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        
        // 执行搜索操作
        
        return true
    }
}

// 使用示例
let searchBarView = SearchBarView(frame: CGRect(x: 0, y: 0, width: 300, height: 40))
searchBarView.animateSearchBar(expanded: true)