iOS中带有空选项的DatePicker

Question

我想使用带有空选项的日期选择器。就像用户不想选择日，月或年一样，会有一个选项“ - ”（空）。

这是一个更好理解的图像

Answer 1

您无法更改UIDatePicker的值。如果要在行上显示自定义值，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
}

Answer 2

对于这种方式，您需要使用DATE PICKER VIEW，这样您就可以使用Picker View，并手动设置日期。

例如：

var monthsArray = ["-", "May", "June", "...", "December"]
var yearsArray = ["-", "2018", "2017", "2016", "...."]
var daysArray = ["1", "2", "-", "3", "4"]