Doing Tic Tac Toe game with GUI interface on java, facing runtime error after including new method
So I am making a tic tac toe game with user friendly GUI interface. I have almost completed the game but there seems to be a problem with my checkWin function. Up to this point, everything was working just fine until I added the checkWin function and the parameters associated it with it. Before I implemented the checkWin function, you would press a button, it would be marked X and then there would be an automated computer move that would place an O randomly on the board where there isn't an X. Code is posted below. When I run the code, and you press a button, the applet just freezes and you can't even exit out of it without end task, ctrl-alt-del... Again, everything worked fine up until the checkWin function and now I'm facing a run-time error.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class TicGUI extends JFrame
{
JFrame frame = new JFrame("TicTacToe"); //Global frame and grid button variables
JButton[][] buttons = new JButton[3][3];
JButton start = new JButton("Start"); //Create start/reset buttons for game
JButton reset = new JButton("Reset");
JOptionPane turn;
int moveCounter = 9;
boolean gameWon = false;
public TicGUI() //Tic tac default constructor which adds and dimensions Jframe
{
super();
frame.setSize(350, 450);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE); //Setting dimension of Jframe and setting parameters
frame.setVisible(true);
frame.setResizable(false);
}
private void checkWin(int row, int col)
{
if(buttons[row][0].getText()==buttons[row][1].getText()&& buttons[row][1].getText()==buttons[row][2].getText())
{
gameWon = true;
System.out.println(buttons[row][0].getText()+ " wins!!!");
}
else if(buttons[0][col].getText()==buttons[1][col].getText()&& buttons[1][col].getText()==buttons[2][col].getText())
{
gameWon = true;
System.out.println(buttons[row][0].getText()+ " wins!!!");
}
}
private void compTurn(int count)
{
int randomMove=count;
Random num = new Random();
randomMove = num.nextInt(randomMove)+1;
while(gameWon ==false)
{
for(int i = 0; i < 3; i++) //Create grid of buttons for tic tac toe game
{
for(int j = 0; j < 3; j++)
{
if(buttons[i][j].isEnabled()==true)
{
randomMove--;
if(randomMove==0 )
{
buttons[i][j].setText("O");
buttons[i][j].setEnabled(false);
moveCounter--;
checkWin(i, j);
}
}
}
}
}
}
private void initialize() //Initialize tic tac toe game board
{
JPanel mainPanel = new JPanel(new BorderLayout()); //create main panel container to put layer others on top
JPanel menu = new JPanel(new BorderLayout());
JPanel game = new JPanel(new GridLayout(3,3)); //Create two more panels with layouts for buttons
frame.add(mainPanel); //add main container panel to frame
mainPanel.setPreferredSize(new Dimension(325,425));
menu.setPreferredSize(new Dimension(300,50)); //Setting dimensions of panels
game.setPreferredSize(new Dimension(300,300));
mainPanel.add(menu, BorderLayout.NORTH); //Add two panels to the main container panel
mainPanel.add(game, BorderLayout.SOUTH);
menu.add(start, BorderLayout.WEST); //Add both start/reset buttons to menu container panel
menu.add(reset, BorderLayout.EAST);
start.addActionListener(new myActionListener());
reset.addActionListener(new myActionListener());
for(int i = 0; i < 3; i++) //Create grid of buttons for tic tac toe game
{
for(int j = 0; j < 3; j++)
{
buttons[i][j] = new JButton(); //Instantiating buttons
buttons[i][j].setText("");
buttons[i][j].setVisible(true);
game.add(buttons[i][j]);
buttons[i][j].addActionListener(new myActionListener()); //Adding response event to buttons
}
}
}
private class myActionListener implements ActionListener
{ //Implementing action listener for buttons
public void actionPerformed(ActionEvent a)
{
//Display X's or O's on the buttons
if(a.getSource() == buttons[0][0]) //Checking which button is pressed
{
buttons[0][0].setText("X");
buttons[0][0].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(0,0);
}
else if(a.getSource() == buttons[0][1])
{
buttons[0][1].setText("X");
buttons[0][1].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(0,1);
}
else if(a.getSource() == buttons[1][0])
{
buttons[1][0].setText("X");
buttons[1][0].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(1,0);
}
else if(a.getSource() == buttons[1][1])
{
buttons[1][1].setText("X");
buttons[1][1].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(1,1);
}
else if(a.getSource() == buttons[1][2])
{
buttons[1][2].setText("X");
buttons[1][2].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(1,2);
}
else if(a.getSource() == buttons[2][2])
{
buttons[2][2].setText("X");
buttons[2][2].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(2,2);
}
else if(a.getSource() == buttons[0][2])
{
buttons[0][2].setText("X");
buttons[0][2].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(0,2);
}
else if(a.getSource() == buttons[2][1])
{
buttons[2][1].setText("X");
buttons[2][1].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(2,1);
}
else if(a.getSource() == buttons[2][0])
{
buttons[2][0].setText("X");
buttons[2][0].setEnabled(false);
moveCounter--;
compTurn(moveCounter);
checkWin(2,0);
}
else if(a.getSource() == start)
{
turn = new JOptionPane("Do you want to go first?\n",JOptionPane.QUESTION_MESSAGE, JOptionPane.YES_NO_OPTION);
start.setEnabled(false);
}
else if(a.getSource() == reset)
{
for(int i = 0; i < 3; i++)
{
for(int j = 0; j < 3; j++)
{
buttons[i][j].setText("");
buttons[i][j].setEnabled(true);
gameWon = false;
}
}
}
}
}
public static void main(String[] args)
{
TicGUI game = new TicGUI(); //main method and instantiating tic tac object and calling initialize function
game.initialize();
}
}
Answer
You need to use the following:
buttons[row][0].getText().equals(buttons[row][1].getText())
instead of:
buttons[row][0].getText()==buttons[row][1].getText()
That also applies to all the other string comparisons in your checkWin method.