Dart: Combine a Date and a Time-CodePudding

I have a simple app in which I can pick a date and also a time:

Both fields return DateTime Objects. What I'm looking for is a good practices to combine the date and the time to a new DateTime object.

What I've done is I create a function:

void combineDateAndTime({int? year, int? month, int? day, int? hour, int? min, int? sec}) {

  if (year != null) {
    dt = DateTime(
        year, dt.month, dt.day, dt.hour, dt.minute, dt.second, dt.millisecond, dt.microsecond);
  }

  if (month != null) {
    dt = DateTime(
        dt.year, month, dt.day, dt.hour, dt.minute, dt.second, dt.millisecond, dt.microsecond);
  }

  if (day != null) {
    dt = DateTime(
        dt.year, dt.month, day, dt.hour, dt.minute, dt.second, dt.millisecond, dt.microsecond);
  }

  if (hour != null) {
    dt = DateTime(
        dt.year, dt.month, dt.day, hour, dt.minute, dt.second, dt.millisecond, dt.microsecond);
  }

  if (min != null) {
    dt = DateTime(
        dt.year, dt.month, dt.day, dt.hour, min, dt.second, dt.millisecond, dt.microsecond);
  }

  if (sec != null) {
    dt = DateTime(
        dt.year, dt.month, dt.day, dt.hour, sec, dt.second, dt.millisecond, dt.microsecond);
  }

}

And by selection a date I call the function with:

combineDateAndTime(day: date.day, month: date.month, year: date.year);

And for selecting a time:

combineDateAndTime(hour: date.hour, min: date.minute);

But I thing there should be a better solution to do this...

CodePudding user response：

Instead of all if condition you can change your combineDateAndTime to this:

void combineDateAndTime(
      {int? year, int? month, int? day, int? hour, int? min, int? sec}) {
    dt = DateTime(
        year ?? dt.year,
        month ?? dt.month,
        day ?? dt.day,
        hour ?? dt.hour,
        min ?? dt.minute,
        sec ?? dt.second,
        dt.millisecond,
        dt.microsecond);
  }

CodePudding user response：

When you get the Date, add it to your DateTime variable like this:

final pickedDay = await pickDay();
if (pickedDay == null) { return; } 
else { 
   final newEventDay = DateTime(
                pickedDay.year,
                pickedDay.month,
                pickedDay.day,
                dt.hour,
                dt.minute,
                dt.second);
   setState(() { dt = newEventDay; });
     }

Then when you get time, add it to the variable like this:

final pickedTime = await pickTime();
if (pickedTime == null) { return; } 
else { 
   final newEventTime = DateTime(
                dt.year,
                dt.month,
                dt.day,
                pickedTime.hour,
                pickedTime.minute,
                pickedTime.second);
   setState(() { dt = newEventTime; });
     }