当UITextfield data isEmpty或filled时，如何禁用/启用按钮？

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var button: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置UITextField的代理为当前视图控制器
        textField.delegate = self
        
        // 初始状态禁用按钮
        button.isEnabled = false
    }
    
    // UITextFieldDelegate方法，监听文本变化事件
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        // 获取文本框的当前文本内容
        let currentText = (textField.text as NSString?)?.replacingCharacters(in: range, with: string) ?? ""
        
        // 检查文本是否为空
        if currentText.isEmpty {
            // 禁用按钮
            button.isEnabled = false
        } else {
            // 启用按钮
            button.isEnabled = true
        }
        
        return true
    }
}