将数据传回UIPickerView

Posted 2021-05-04

我正在创建计时器应用，我希望用户能够编辑现有计时器。例如，当用户单击特定的计时器时，他可以编辑小时，分钟和秒，我最初是从UIPickerView中获得的。

我正在使用此代码来获取新计时器的小时，分​​钟和秒：

    var hour: Int = 0
    var minutes: Int = 0
    var seconds: Int = 0
    var name: String = ""

    var totalSeconds: Int {
        return hour * 3600 + minutes  * 60 + seconds
    }

}
     extension TimerSelectViewController: UIPickerViewDelegate, UIPickerViewDataSource {

         func numberOfComponents(in pickerView: UIPickerView) -> Int {
             return 3
         }

         func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
             switch component {
             case 0:
                 return 25
             case 1, 2:
                 return 60
             default:
                 return 0
             }
         }

         func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
            return pickerView.frame.size.width/4
         }

         func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
             switch component {
             case 0:
                 return "(row) hr"
             case 1:
                 return "(row) min"
             case 2:
                 return "(row) sec"
             default:
                 return ""
             }
         }
         func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
             switch component {
             case 0:
                 hour = row
             case 1:
                 minutes = row
             case 2:
                 seconds = row
             default:
                 break;
             }
         }

但是当用户想要编辑计时器而不创建新计时器时，如何将数据传递回UIPickerView？

答案

UIPickerView有一种用于预选择行的方法：https://developer.apple.com/documentation/uikit/uipickerview/1614382-selectrow

例如：

let picker = UIPickerView()
// 14:00:00 or 2:00:00 PM, add more select commands as needed
picker.selectRow(14, inComponent: 0, animated: false)