ios - iOS 中带有空选项的 DatePicker

Question

我想使用带空选项的日期选择器。就像如果用户不想选择日、月或年，则会有一个“-”(空)选项。

为了更好的理解，这里有一张图片

Answer 1

您不能更改 UIDatePicker 的值。如果您希望自定义值显示在行上，您可以使用 UIPickerView。显示月份和“-”的示例代码是:

let months: [String] = ["-" ,"January", "February", "March",
                        "April", "May", "June",
                        "July", "August", "September",
                        "October", "November", "December"]

let pickerView: UIPickerView = UIPickerView()

pickerView.delegate = self
pickerView.dataSource = self

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

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

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

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
// do whatever you want when specific row is selected
}