How to change color to opposite theme in cupertino widget?

Question

I have two buttons on the same page that bring up a date picker CupertinoDatePicker. One button just opens the picker, no additional customizations. The second one opens a picker that has a predefined theme locally opposite to the one currently enabled for the app. How can I change the color of the elements of one of them using the theme setting? My code:

CupertinoButton(
                onPressed: _showDialog,
                child: const Text(
                  'Select date',
                  style: TextStyle(
                    fontSize: 22.0,
                  ),
                ),
              ),

void _showDialog() {
    showCupertinoModalPopup<void>(
      context: context,
      builder: (BuildContext context) => Container(
        height: 216,
        padding: const EdgeInsets.only(top: 6.0),
        margin: EdgeInsets.only(
          bottom: MediaQuery.of(context).viewInsets.bottom,
        ),
        color: CupertinoColors.systemBackground.resolveFrom(context),
        child: SafeArea(
          top: false,
          child: CupertinoDatePicker(
            initialDateTime: _date,
            mode: CupertinoDatePickerMode.date,
            use24hFormat: true,
            onDateTimeChanged: (DateTime newDate) {
              setState(() => _date = newDate);
            },
          ),
        ),
      ),
    );
  }

Answer 1

For setState in dialog modal , must wrap first widget in modal into statefullBuilder. You cant setState normally in modal dialog.

See example code:

showModalBottomSheet(
context: context,
builder: (context) {
  return StatefulBuilder(
      builder: (BuildContext context, StateSetter setState) {
    return Container(
      height: heightOfModalBottomSheet,
      child: RaisedButton(onPressed: () {
        setState(() {
          heightOfModalBottomSheet += 10;
        });
      }),
    );
  });});