Swift 动态 UIPickerView答案

【问题标题】：Swift Dynamic UIPickerViewSwift 动态 UIPickerView
【发布时间】：2019-02-15 06:10:12
【问题描述】：

我觉得我很接近了，因为下面的代码适用于静态 UIPickerViews，但我正在尝试根据第一个选择动态设置我的pickerview，尽管查看了教程和搜索，但我无法完全解决这个问题。例如，如果您在 myPickerData 中选择“Brown”，则 myPickerData2 中应仅显示“Undergraduate”，或者如果您选择“Dartmouth”，则应仅获得“Undergraduate”和“MBA”，如果选择“Columbia”或“Harvard”则最后，你得到“本科”、“JD”、“MBA”。

var myPickerData = ["Select Your Dream College", “Brown", "Columbia", “Dartmouth”,  "Harvard" ]

var myPickerData2 = ["Undergraduate", "JD", "MBA"]

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 2
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {

    if component == 0 {
        return myPickerData.count
    }

    return myPickerData2.count
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

    if component == 0 {
        return myPickerData[row] as String
    }
    return myPickerData2[row] as String
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    uniSelected = myPickerData[pickerView.selectedRow(inComponent: 0)]

    collegeSelected = myPickerData2[pickerView.selectedRow(inComponent: 1)]
}

【问题讨论】：

标签： swift dynamic components uipickerview

【解决方案1】：

你可以试试

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

     if component == 0 {

         let str = myPickerData[row]

         if str == "Brown" {

            myPickerData2 = ["Undergraduate"]
         }
         else if str == "Dartmouth" {

            myPickerData2 = ["Undergraduate", "MBA"]
         }
         else {

            myPickerData2 = ["Undergraduate", "JD", "MBA"]

         }

         pickerView.reloadComponent(1)

      }
      else {

         uniSelected = myPickerData[pickerView.selectedRow(inComponent: 0)]

         collegeSelected = myPickerData2[pickerView.selectedRow(inComponent: 1)]
      }

}

这可能包含重复，但您可以尝试一下

let mainDic:[String:[String]] = ["Select Your Dream College":[],
                 "Brown":["Undergraduate"],
                 "Dartmouth":["Undergraduate", "MBA"],
                 "Columbia":  ["Undergraduate", "JD", "MBA"],
                 "Harvard",["Undergraduate", "JD", "MBA"]]

然后

myPickerData2 = mainDic[myPickerData[row]]!

pickerView.reloadComponent(1)

并在组件 0 中使用它

myPickerData = Array(mainDic.keys)

使您的数据源为mainDic，并将键处理为myPickerData，当前选择的键的值为myPickerData2

编辑：在viewDidLoad

myPickerData = Array(mainDic.keys)
myPickerData2 = mainDic["Select Your Dream College"]! // it's default or simply []

【讨论】：

这非常有帮助，并且认为这是解决问题的方法。但是，是否有更清洁/可扩展的方法来做到这一点？我只为每个数据源数组列出了 3 个，并想象一个更大的数组将成为一个巨大的 if 语句。 IE，如果我在 myPickerData1 中加载 15 个潜在选择，那么 if else 语句会变得非常混乱。
好的，dict 数组是有道理的，但是我原来的 func 方法有什么变化？试图想象我的原始代码将如何变化。再次感谢！
init myPickerData 和 myPickerData2 从 mainDic ,,, 见编辑
试图用字典实现你的建议，但遇到了很多问题，所以只使用你原来的 if 语句 haaa