How to change object value in a loop in Dart - dart

Question

I'm a total newbie in Dart and I've a lot of issues trying to change a member value of an Object inside a loop.
I've my object so defined:
class Cell {
int magicnum, x, y;
Cell(this.magicnum);
toString() {
return ("$magicnum - [$x][$y]");
}
}
I create a List of List of Cell (2d array) and then I need to fill x and y value according to position of each object in array.
for (int x = 0; x < DIM; x++) {
for (int y = 0; y < DIM; y++) {
grids[x][y].x = x;
grids[x][y].y = y;
}
}
This obviosly doesn't work because in Dart everything (also integer) is an Object and so, all Cell objects in my array have the same x and y value (they all got a reference to the same object).
How can I do?
Thanks
#julemand101
Array is made this way:
List<Cell> cells = List<Cell>.generate(DIM, (i) => Cell(i + 1));
List<List<Cell>> grids = List<List<Cell>>();
for (int i = 0; i < DIM; i++) {
grids.add(shuffleCell(cells));
}

Answer 1

You problem is you are not actually cloning each Cell object when you are doing the following (taken from the code example from comments):
List<Cell> newlist = List<Cell>.from(items);
Instead, you are creating a new List containing the same references to Cell objects as the previous list of items.
To create a copy of Cell objects you need to implement a clone method like:
class Cell {
int magicnum, x, y;
Cell(this.magicnum);
Cell.from(Cell cell)
: magicnum = cell.magicnum,
x = cell.x,
y = cell.y;
}
And do the following to iterate each element of the old list, create a new Cell object for each element and convert the result to a new List:
List<Cell> newlist = items.map((item) => Cell.from(item)).toList();