UIPickerView报告错误的行

Question

当我从上到下遍历此UIPickerView时，会正确报告每个元素的行。但是，当＆＃34;选择3＆＃34;时，从底部到顶部遍历UIPickerView。被轻拍，行重置为零，它应该实际为2.我添加了视觉证明的标签 - 它闪烁＆＃34; 2＆＃34;，然后如所描述的那样在遍历UIPickerView时将自身重置为零。显然，不能依赖显示元素和实际行之间的关系是准确的打破事情。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＆＃34;转动标签时更改标签。在选择器视图中，实现委托方法pickerView(_:didSelectRow:inComponent:)。