Add Index of 2-dimensional Array to to the end of List in Java

Question

I am working on a small game where the player clicks a button whichs value is from a 2-dimensional Array.This is how the game looks In case the player wants to revert his action I want to save the steps the player took in a List, and when he clicks the "revert"-button the last item of the list gets reverted. Problem is I don't know how to the save the index of a 2-dimensional Array to a list.

My code is far for the array is following

for (int i = 0; i < buttons.length; i++) {
        for (int j = 0; j < buttons[i].length; j++) {
            counter++;
            buttons[i][j] = new JButton("" + counter);

            buttons[i][j].setBackground(Color.white);
            buttons[i][j].addActionListener(new ButtonPress());
            fenster.add(buttons[i][j]);

And the code for the ActionListener is here:

public void actionPerformed(ActionEvent e) {

        amountMoves++;
        moves.setText("Moves: " + amountMoves);

        int x = 0;
        int y = 0;
        for (int i = 0; i < buttons.length; i++) {
            for (int j = 0; j < buttons[i].length; j++) {
                if (((JButton) e.getSource()).equals(buttons[i][j])) {
                    x = i; 
                    y = j;
                    break;
                }
            }
        }
    }

Lists aren't my strongpoint so so far I only have this:

    ArrayList<Integer> steps = new ArrayList<Integer>();

I know I can add a element with steps.add() and delete the last element with steps.remove(steps.size() - 1);, but that's all so far

Any help is greatly appreciated

EDIT: With the help of @Johnny Mopp and @SSP I figured out what to do. First I created a List of the type String ArrayList<String> steps = new ArrayList<String>(); (you can alternativly use a List of the type JButton) and add it in the Actionlister with steps.add(buttons[i][j].getText());

By reverted, do you mean that the last item in the List gets deleted, or that it becomes equal to the one before it? — StealthDroid
– StealthDroid, Commented Sep 24, 2019 at 19:20
There are lots of options. You might store the actual button (ArrayList<Button>)? Or use an array of Pair..... — 001
– 001, Commented Sep 24, 2019 at 19:28

SSP · Accepted Answer · 2019-09-24 19:21:24Z

1

create a Lists of list :-

ArrayList<ArrayList<Integer>> steps = new ArrayList<>();

if you get row 2 and column 2 data to be saved, Save value like below:-

steps.get(1).add(1{index of column},2{value to be stored});

If you are adding element for first time, You need to instantiate object like below:-

if(steps.get(1) == null){
    steps.get(1) = new ArrayList<>();
}

Accessing data

 steps.get(1).get(2);

answered Sep 24, 2019 at 19:21

SSP

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