Creating a dynamic 2D matrix in Java

Question

I want a dynamic matrix, number rows and columns unkonw, filling it by clicking on a button. Bu there is more: I don't want to add entire rows, but just one cell at the time, one click = one cell added. Of course not randomly : 1st cell of 1st row, 2nd cell of 1st row... and then the same of the 2nd row and so one...

I know about UJMP, ArrayList, but it's not quite what I'm looking for. Please be accurate on your answer, thank you in advance.

Answer 1

Use this:

List<List<Integer>> dynamicMatrix = new ArrayList<List<Integer>>();

dynamicMatrix.add(new ArrayList<Integer>());
dynamicMatrix.add(new ArrayList<Integer>());
dynamicMatrix.add(new ArrayList<Integer>());

dynamicMatrix.get(0).add(6);
dynamicMatrix.get(0).add(7);
dynamicMatrix.get(0).add(8);

System.out.println(dynamicMatrix.get(0).get(0)); // 6
System.out.println(dynamicMatrix.get(0).get(1)); // 7
System.out.println(dynamicMatrix.get(0).get(2)); // 8