Flutter 颤振显示时间选择器验证

根据设备平台的不同，有两种类型的时间选择器。两个时间选择器都需要使用maxtime和mintime进行验证。有什么帮助吗 验证示例：mintime=当前时间 最大时间=最小时间+12小时

_selectTime(BuildContext context) async {
    final ThemeData theme = Theme.of(context);
    assert(theme.platform != null);
    switch (theme.platform) {
      case TargetPlatform.android:
        return buildMaterialTimePicker(context);
      case TargetPlatform.iOS:
        return buildIOSTimePicker(context);
    }
}

buildMaterialTimePicker(BuildContext context) async {
format(Duration d) => d.toString().split('.').first.padLeft(8, "0");
var picker = await showTimePicker(
    context: context,
    initialTime: TimeOfDay.now(),
    builder: (context, child) {
      return MediaQuery(
        data: MediaQuery.of(context).copyWith(alwaysUse24HourFormat: true),
        child: child,
      );
    });
final time = Duration(hours: picker.hour, minutes: picker.minute);
textInput.text = format(time);
setTimeValues(textInput.text);
}

buildIOSTimePicker(BuildContext context) {
DatePicker.showTimePicker(context,
    showTitleActions: true, 
     
    currentTime: DateTime.now(), onConfirm: (time) {
  textInput.text = new DateFormat('HH:mm:00').format(time);
  setTimeValues(textInput.text);
});

}

有什么帮助吗