Disable some of the flutter checkboxes

I'm making a cinema app. I made the seat selection using checkbox. I would like to deactivate the checkbox of the reserved seat among 200 seats (column: 10 row: 20).

I know that if I input onChanged of the checkbox as null, it will be disabled. The problem is that I created 200 CheckBoxes in one CheckBox class. Is there a part to disable only a part of it?

Positioned(
            top: 45,
            left: 16,
            right: 16,
            child: GridView.count(
              shrinkWrap: true,
              crossAxisCount: 20,
              mainAxisSpacing: 2,
              crossAxisSpacing: 2,
              children: List.generate(200, (index) {
                int column = (index % 200).toInt();

                return Theme(
                  data: ThemeData(
                    primarySwatch: Colors.red,
                    unselectedWidgetColor: Colors.blueGrey,
                  ),
                  child: Checkbox(
                      checkColor: Colors.white,
                      value: widget.seat![widget.index!][column],
                      onChanged: (selected) {
                        setState(() {
                          // widget.selected[row][column] = selected!;
                          if (widget.seat![widget.index!][column] == false) {
                            widget.seat![widget.index!][column] = true;
                            seat_select++;
                          } else if (widget.seat![widget.index!][column] == true) {
                            widget.seat![widget.index!][column] = false;
                            seat_select--;
                          }
                        });
                      }),
                );
              }),
            ),
          ),