opens an Empty BottomSheet on button press

gistfile1.txt

 MaterialButton(
                child: Text(
                  "Cupertino date Picker",
                  style: TextStyle(color: Colors.white),
                ),
                color: Colors.redAccent,
                onPressed: () {
                  showModalBottomSheet(
                      context: context,
                      builder: (BuildContext builder) {
                        return Container(
                            height: MediaQuery.of(context).copyWith().size.height / 3,
                           );
                      });
                },
              ),