从UIPickerview获取文本并在UIAlert内移动文本字段

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
    
    var selectedText: String = ""
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建和配置UIPickerView
        let pickerView = UIPickerView()
        pickerView.dataSource = self
        pickerView.delegate = self
        
        // 创建UIAlertController
        let alertController = UIAlertController(title: "选择文本", message: nil, preferredStyle: .alert)
        
        // 添加文本字段到UIAlertController
        alertController.addTextField { textField in
            textField.text = self.selectedText
        }
        
        // 将UIPickerView添加到UIAlertController
        alertController.view.addSubview(pickerView)
        
        // 设置UIPickerView的位置和大小
        pickerView.translatesAutoresizingMaskIntoConstraints = false
        pickerView.centerXAnchor.constraint(equalTo: alertController.view.centerXAnchor).isActive = true
        pickerView.topAnchor.constraint(equalTo: alertController.view.topAnchor, constant: 60).isActive = true
        
        // 创建UIAlertAction并添加到UIAlertController
        let okAction = UIAlertAction(title: "确定", style: .default) { _ in
            // 获取文本字段的值
            if let textField = alertController.textFields?.first {
                self.selectedText = textField.text ?? ""
            }
        }
        alertController.addAction(okAction)
        
        // 显示UIAlertController
        present(alertController, animated: true, completion: nil)
    }
    
    // MARK: - UIPickerViewDataSource
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1 // 单列选择器
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return 3 // 选择器中的行数
    }
    
    // MARK: - UIPickerViewDelegate
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return "选项 \(row + 1)" // 返回选择器中每行的文本
    }
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectedText = "选项 \(row + 1)" // 更新所选文本
    }
}