ios - 使 UIPickerView 依赖于选定的行(Swift)

Question

这是我想要实现的目标

使第二个 UIPickerView 依赖于当前选中的行

Answer 1

1.set dataSource or delegate from storyboard

2.从 Storyboard中设置PickerOne的标签101。

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

@IBOutlet weak var pickerTwo: UIPickerView!

let pickerOneOptions = ["TV", "RADIO"]
let pickerTwoTVOptions = ["ABC", "SBS"]
let pickerTwoRadioOptions = ["TripleJ", "107.0", "CBS"]
var pickerOneSelectedRow:Int = 0

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

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

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
 if pickerView.tag == 101 { //pickerOne
  return pickerOneOptions.count
 }  else { //pickerTwo
  if self.pickerOneSelectedRow == 0 {
    return pickerTwoTVOptions.count
  } else {
    return pickerTwoRadioOptions.count
  }
 }
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
 if pickerView.tag == 101 { //pickerOne
  return pickerOneOptions[row]
 }  else { //pickerTwo
  if self.pickerOneSelectedRow == 0 {
    return pickerTwoTVOptions[row]
  } else {
    return pickerTwoRadioOptions[row]
  }
 }
return nil
}

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
 if pickerView.tag == 101 {
  self.pickerOneSelectedRow = row
  pickerTwo.reloadAllComponents()
  }
 }
}