How to set the size of a Flutter Container (fit a percentage of the device screen)

As a brief note, on this page I found this example of how to set the size of a Flutter Container:

    height: MediaQuery.of(context).copyWith().size.height / 3,

After looking at what the copyWith method does:

copyWith: Creates a copy of this media query data but with the given fields replaced with the new values.

I don’t think it’s needed in this example, so you should get the exact same effect with this code:

    height: MediaQuery.of(context).size.height / 3,

For instance, I use this code in a production app to set the size of this Flutter Container to be one-fourth of the screen height:

    height: MediaQuery.of(context).size.height / 4,
    child: CupertinoDatePicker(
        mode: CupertinoDatePickerMode.time,
        initialDateTime: DateTime(1969, 1, 1, _timeOfDay.hour, _timeOfDay.minute),
        onDateTimeChanged: (DateTime newDateTime) {
            var newTod = TimeOfDay.fromDateTime(newDateTime);
        use24hFormat: false,
        minuteInterval: 1,

In summary, if you wanted to see how to set the size of a Flutter Container — in this case, the Container height — I hope these examples are helpful.