xcode - 如何在一个 View Controller 中使用两个 UIPickerViews？

Question

我在一个 View Controller 中有两个 UIPickerController。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 View 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拣货员工作呢？假设我的第二个选择器 View 称为 location(另一个称为 position)。我尝试在 location 的选择器 View 方法中复制代码，但它不起作用。

Answer 1

这是我的解决方案:

• 在 Storyboard中，将两个 UIPickerView 实例添加到您的 View
• 在“属性检查器”下将第一个选择器的标签设置为1，将第二个选择器设置为2
• control + 从每个选择器拖动到顶部黄色 View Controller 图标并选择 dataSource。重复相同的选择 delegate

• 将 UIPickerViewDataSource 和 UIPickerViewDelegate 添加到您的 View Controller :

  class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
  

• 在您的 View Controller 类中，为选择器创建空数组:

  var picker1Options = []
  var picker2Options = []
  

• 在 viewDidLoad() 中，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(delegate)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])"
      }
  }