如何在 UIPickerView 中获取用户选择并在其他地方使用它？

Question

我要做的就是根据用户在选择器菜单中选择的内容更改 min avg 和 max 的值，以便我可以在 MinC AvgC 和 MaxC 标签计算中使用它们。例如，如果用户选择 a1，则 min = 10，avg = 15，max = 20，但如果用户选择 a2，我希望 min = 20，avg = 25，max = 30。请帮助，谢谢。感谢您的时间、精力和支持。下面是我的代码，目前正在运行，没有任何错误：

class ViewController: UIViewController, UIPickerViewDelegate, UITextFieldDelegate{

    @IBOutlet var PLabel: UILabel!

    @IBOutlet weak var C: UITextField!

    @IBOutlet var MinC: UILabel!
    @IBOutlet var AvgC: UILabel!
    @IBOutlet var MaxC: UILabel!

    var min = 0
    var avg = 0
    var max = 0

    var P = ["a1","a2","a3","a4"]

    var CFiller = ["0"]

    override func viewDidLoad()
    {super.viewDidLoad()
     PLabel.text = P[0]
     MinC.text = CFiller[0]
     AvgC.text = CFiller[0]
     MaxC.text = CFiller[0]
     C.keyboardType = UIKeyboardType.NumberPad}


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

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

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

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

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
    { var PSelected = P[row]
          PLabel.text = PSelected}





    @IBAction func CalcButton(sender: AnyObject)
        {if let ic = Int (C.text!)
        {MinC.text = "\(min * ic)"
         AvgC.text = "\(avg * ic)"
         MaxC.text = "\(max * ic)"}}

}

Answer 1

在我看来，您只需要使用 switch 语句即可实现目标。

这可能看起来像这样：

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
{ var PSelected = P[row]
PLabel.text = PSelected

switch PSelected {
case "a1":
    min = 10
    avg = 15
    max = 20
case "a2":
    min = 20
    avg = 25
    max = 30
    ...
default:
    break
}
}

如果您愿意，也可以更有效地进行设置，如下所示：

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
{ var PSelected = P[row]
PLabel.text = PSelected

var increment = 10
min = 10
avg = 15
max = 20

min += increment*row //if a1, then row == 0, so nothing is added
avg += increment*row
max += increment*row

}