使用swift 4搜索多个按键

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    let keysToSearch = ["A", "B", "C", "D", "E"] // 要搜索的按键数组
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let searchTextField = UITextField(frame: CGRect(x: 50, y: 100, width: 200, height: 30))
        searchTextField.borderStyle = .roundedRect
        searchTextField.placeholder = "输入关键字"
        searchTextField.delegate = self
        view.addSubview(searchTextField)
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let searchText = (textField.text! as NSString).replacingCharacters(in: range, with: string)
        
        for key in keysToSearch {
            if key.contains(searchText) {
                print("匹配的按键：\(key)")
                // 在这里执行相应的操作，例如显示匹配的按键在界面上
            }
        }
        
        return true
    }
}