UIPickerView 报告不正确的行

Question

当我自上而下遍历此 UIPickerView 时，每个元素的行都被正确报告。然而，从下到上遍历 UIPickerView，当 "Choice 3" 被点击时，该行将自身重置为零，而实际上它应该是 2。我添加了视觉证明的标签——它闪烁“2”，然后自行重置如所述遍历 UIPickerView 时为零。显然，不能依赖于显示元素和实际行之间的关系是否准确会破坏事情。不知道为什么这不起作用...

class ViewController3: UIViewController, UITextFieldDelegate, UIPickerViewDelegate, UIPickerViewDataSource {

   @IBOutlet weak var picker: UIPickerView!
    @IBOutlet weak var textLabel: UILabel!


    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return 4
    }

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



 func pickerView(_ pickerView: UIPickerView,titleForRow row: Int,forComponent component: Int) -> String?  {
          textLabel.text = String(row)
       return pickerValues[row]   
    }


    let pickerValues = ["Choice 1", "Choice 2", "Choice 3","Choice 4"]

Answer 1

如果目标是每次用户转动选择器视图 "wheel" 时更改标签，请实现委托方法 pickerView(_:didSelectRow:inComponent:)。

UIPickerView 报告不正确的行

UIPickerView reports an incorrect row

uipickerview

ios

swift