如何在一个视图控制器中使用两个 UIPickerView？

我有两个UIPickerControllers 在一个视图控制器中。我可以让一个工作，但是当我添加第二个时，我的应用程序崩溃了。这是我用于一个选择器视图的代码：

import UIKit

class RegisterJobPosition: UIViewController, UIPickerViewDelegate {

    @IBOutlet weak var positionLabel: UILabel!

    var position = ["Lifeguard", "Instructor", "Supervisor"]

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    func numberOfComponentsInPickerView(PickerView: UIPickerView!) -> Int
    {
        return 1
    }

    func pickerView(pickerView: UIPickerView!, numberOfRowsInComponent component: Int) -> Int
    {
        return position.count
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String!
    {
        return position[row]
    }

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {        
        positionLabel.text = position[row]
    }
}

现在，我怎样才能让第二个选择器工作呢？假设我的第二个选择器视图被称为location（另一个叫做position）。我尝试在选择器视图方法中复制代码location但它不起作用。

这是我的解决方案：

• 在故事板中添加两个UIPickerView您的视图的实例
• 将第一个选择器的标签设置为1并设置2对于“属性检查器”下的第二个选择器
• control + drag from each picker to the top yellow view controller icon and choose dataSource. Repeat the same choosing delegate

• add UIPickerViewDataSource and UIPickerViewDelegate到你的视图控制器：

  class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
  

• 在视图控制器类中，为选择器创建空数组：

  var picker1Options = []
  var picker2Options = []
  

• In viewDidLoad()，用您的内容填充数组：

  picker1Options = ["Option 1","Option 2","Option 3","Option 4","Option 5"]
  picker2Options = ["Item 1","Item 2","Item 3","Item 4","Item 5"]
  

• 实现委托和数据源方法：

  func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
      return 1
  }
  
  func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
      if pickerView.tag == 1 {
          return picker1Options.count
      } else {
          return picker2Options.count
      }
  }
  
  func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
      if pickerView.tag == 1 {
          return "\(picker1Options[row])"
      } else {
          return "\(picker2Options[row])"
      }
  }