如何通过单击UItextfield进行输入，以编程方式打开视图进行选择

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    
    let options = ["Option 1", "Option 2", "Option 3"] // 预定义选项数组
    var selectedOption: String? // 保存用户选择的选项
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let textField = UITextField(frame: CGRect(x: 100, y: 100, width: 200, height: 30))
        textField.borderStyle = .roundedRect
        textField.placeholder = "Select an option"
        textField.addTarget(self, action: #selector(showPickerView), for: .touchDown)
        view.addSubview(textField)
    }
    
    @objc func showPickerView() {
        let pickerView = UIPickerView()
        pickerView.delegate = self
        pickerView.dataSource = self
        
        let alertController = UIAlertController(title: "Select an option", message: nil, preferredStyle: .actionSheet)
        alertController.view.addSubview(pickerView)
        
        let doneAction = UIAlertAction(title: "Done", style: .default) { _ in
            if let option = self.selectedOption {
                // 处理用户选择的选项
                print("Selected option: \(option)")
            }
        }
        alertController.addAction(doneAction)
        
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
        alertController.addAction(cancelAction)
        
        present(alertController, animated: true, completion: nil)
    }
    
    // MARK: - UIPickerViewDelegate
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return options[row]
    }
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectedOption = options[row]
    }
    
    // MARK: - UIPickerViewDataSource
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return options.count
    }
}