所选的第一个组件确定第二个组件的内容不同步的UIPickerView

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    // 返回选择器的列数
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    // 返回指定列的行数
}

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
    
    let pickerView = UIPickerView()
    var firstComponentData = ["Option 1", "Option 2"]
    var secondComponentData = [["SubOption 1-1", "SubOption 1-2"], ["SubOption 2-1", "SubOption 2-2"]]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        pickerView.dataSource = self
        pickerView.delegate = self
        
        view.addSubview(pickerView)
        pickerView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            pickerView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            pickerView.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }
    
    // MARK: - UIPickerViewDataSource
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 2
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        if component == 0 {
            return firstComponentData.count
        } else {
            return secondComponentData[pickerView.selectedRow(inComponent: 0)].count
        }
    }
    
    // MARK: - UIPickerViewDelegate
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if component == 0 {
            return firstComponentData[row]
        } else {
            return secondComponentData[pickerView.selectedRow(inComponent: 0)][row]
        }
    }
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if component == 0 {
            pickerView.reloadComponent(1)
        }
    }
}