Evaluate the winning states of Tic-Tac-Toe

Question

I want to try to evaluate the winning state in the tic-tac-toe below game.

So what I end up doing normally is trying to use the getText() method on the buttons in a for loop and evaluate for example if cells[0][i].getText() is equal to cells[0][1] and cells[0][2].
Then I see if cells[0][2] aren't blank (so not equal to " ") then that would finish the first row.
The problem is that this doesn't work and I would appreciate if someone provides me with a better alternative to this approach, if there is any.

package tictactoe;

import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;

import javax.swing.JFrame;

public class TicTacToe implements ActionListener
{
   JFrame window;
   static JButton[][]cells=new JButton[3][3];
   boolean playing;
   char turn='X';
        public TicTacToe()
        {
           //SETS UP THE WINDOW
            window=new JFrame("TicTacToe");
            window.setSize(new Dimension(400,400));
            window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            window.setResizable(false);
            //**********************//
            createCells();

            window.setVisible(true);
        }
public static void main(String[] args) 
{
  new TicTacToe();
}
private void createCells()
{
  window.setLayout(new GridLayout(3,3));
   for(int i=0;i<cells.length;i++)
   {
       for(int j=0;j<cells.length;j++)
       {
           cells[i][j]=new JButton();
           cells[i][j].addActionListener(this);
           window.add(cells[i][j]);
       }
   }
}

@Override
public void actionPerformed(ActionEvent e) 
{
    playing=true;
    JButton _buttonPressed=(JButton)e.getSource();
      while(playing)
      {
          if(turn=='X')
          {
             _buttonPressed.setText("X");
             _buttonPressed.setEnabled(false);
             turn='O';
          }
          else
          {
              _buttonPressed.setText("O");
              _buttonPressed.setEnabled(false);
          }
     }

}
}

Answer 1

Good approach to finding the winner of Tic-Tac-Toe:

You only ever need to check if the last move by a user caused the board to go into a winning state. You also know that the user placed either an X or an O at position board[x][y].

it will look something like this:

public bool gameOver(cells, x, y)
   if cells[0,y] == cells[1,y] == cells[2,y]
      //win on vertical line
   if cells[x,0] == cells[x,1] == cells[x,2]
      //win on horizontal line
   if x == y and cells[0,0] == cells[1,1] == cells[2,2]
      //win on diagonal
   if x == y and cells[0,2] == cells[1,1] == cells[2,0]
      //win on other diagonal
   return false

Answer 2

I'm not seeing where you are evaluating the winning state, but try removing the infinite loop from the click listener.

@Override
public void actionPerformed(ActionEvent e) {
    JButton _buttonPressed = (JButton) e.getSource();

    _buttonPressed.setText("" + turn);
    _buttonPressed.setEnabled(false);
    if (turn == 'X') {
        turn = 'O';
    } else {
        turn = 'X';
    }
}

---

And these are mostly suggestions, so feel free to ignore this, if you wish.

Make the TicTacToe class be a JFrame itself - no need to instantiate one.

public class TicTacToe extends JFrame implements ActionListener {
    private JButton[][] cells = new JButton[3][3];
    private char turn = 'X';
    private boolean playing;

    public TicTacToe() {
        setTitle("TicTacToe");
        setSize(new Dimension(400, 400));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        createCells();
        pack();
    }

Secondly, the recommended way to start a Swing app, is on its own thread like so

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            TicTacToe ttt = new TicTacToe();
            ttt.setVisible(true);
        }
    });
}