int row = 3;
int col = 4;

var twoDList = List.generate(row, (i) => List(col), growable: false);

//For fill;
twoDList[0][1] = "deneme";

print(twoDList);

// [[null, deneme, null, null], [null, null, null, null], [null, null, null, null]]

您的二维列表有 3 行 4 列.

Your 2D list having 3 rows and 4 columns.