Question

I’m getting an error that I don’t realy understand why. It is a tictactoe game(n x n)
here is the table class

public class Table {

private int columns;
private int rows;
private int wincells;
private PieceType[][] table;

public Table() {
}

public Table(int rows, int columns, int wins) {
    this.columns = columns;
    this.rows = rows;
    this.wincells = wins;
    table = new PieceType[rows][columns];
    fillEmpty();
}
public void fillEmpty() {
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < columns; ++j) {
            table[i][j] = PieceType.None;
        }
    }
}

public PieceType getElement(int i, int j) {
    return table[i][j];
}

its the getElement() method giving the error after i call the function with
game.move(e.x, e.y);

public void widgetSelected(SelectionEvent e) {
        Button button = (Button) e.getSource();
        MoveResult moveResult = game.move(e.x, e.y);
        if (game.getCurrentPlayer().getPieceType() == PieceType.Cross)
            button.setText("x");
        else
            button.setText("0");
        switch (moveResult) {
        case ValidMove: {
            buttonTable[gridData.horizontalIndent][gridData.verticalIndent]
                    .setText("X");
            game.changePlayer();
        }
        case WinMatch:
            disableButtons();

        case Draw:
            disableButtons();
        }

this is where the x and Y get the value

   for (int i = 0; i < rows; ++i)
        for (int j = 0; j < cols; ++j) {

            gridData.heightHint = 45;
            gridData.widthHint = 45;

            Button button = new Button(buttonpanel, SWT.PUSH);
            button.setLayoutData(gridData);
            button.setData(new Cell(i,j));
            buttonTable[i][j] = button;
            buttonTable[i][j]
                    .addSelectionListener(new buttSelectionListener());

any ideas on what the problem can be? is it from the game.move(e.x, e.y)? Am I not calling it properly?

StackTrace?:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at backview.Table.getElement(Table.java:42)
at backview.Game.move(Game.java:56)
at frontview.MainGui$buttSelectionListener.widgetSelected(MainGui.java:159)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at frontview.MainGui.<init>(MainGui.java:55)
at main.Main.main(Main.java:18)

here is the method calling

if(table.getElement(x, y) != PieceType.None) return MoveResult.InvalidMove;

Answer 1

You probably want to get the Cell from the Button data and use the i,j coordinates to call getElement().

Note: A couple of comments on your Table class. The default constructor doesn’t make sense if you already know the initial size of the table. If that is the case, make columns, rows and wincells final so they cannot be modified during the game. Also, check that the coordinates provided in getElement() are within the array bounds:

public PieceType getElement(int i, int j) {
    if ((i < 0) || (i >= rows) ||
        (j < 0) || (j >= columns)) {
        return null;
    }

    return table[i][j];
}