我有完整的代码，唯一的问题是它不输出应该说“玩家X胜出”或“玩家O胜出”的窗口。
以下代码给了我例外：
Errors:Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException.：
package TicTac;
// ... imports ...
public class TicTac {
private JFrame frame;
private String startGame = "X";
private int xCount = 0;
private int oCount = 0;
private JLabel btn1;
private JLabel btn2;
private JLabel btn3;
private JLabel btn4;
private JLabel btn5;
private JLabel btn6;
private JLabel btn7;
private JLabel btn8;
private JLabel btn9;
private JTextField txtCountX;
private JTextField txtCountO;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TicTac window = new TicTac();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public TicTac() {
initialize();
}
private void gameScore()
{
txtCountX.setText(String.valueOf(xCount));
txtCountO.setText(String.valueOf(oCount));
}
private void choosePlayer()
{
if (startGame.equalsIgnoreCase("X"))
{
startGame="O";
}
else
{
startGame="X";
}
}
private void WinningGame()
{
String b1 = btn1.getText();
String b2 = btn2.getText();
String b3 = btn3.getText();
String b4 = btn4.getText();
String b5 = btn5.getText();
String b6 = btn6.getText();
String b7 = btn7.getText();
String b8 = btn8.getText();
String b9 = btn9.getText();
if(b1==("X") && b2==("X") && b3==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b4==("X") && b5==("X") && b6==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b7==("X") && b8==("X") && b9==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b1==("X") && b4==("X") && b7==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b2==("X") && b5==("X") && b8==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b3==("X") && b6==("X") && b3==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b1==("X") && b5==("X") && b9==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b3==("X") && b5==("X") && b7==("X") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer X wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
///////PLayer 0 winning combinations///////
if(b1==("O") && b2==("O") && b3==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b4==("O") && b5==("O") && b6==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b7==("O") && b8==("O") && b9==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
xCount++;
gameScore();
}
if(b1==("O") && b4==("O") && b7==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b2==("O") && b5==("O") && b8==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b3==("O") && b6==("O") && b3==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b1==("O") && b5==("O") && b9==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic Tac Toe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
if(b3==("O") && b5==("O") && b7==("O") )
{
JOptionPane.showMessageDialog(frame, "PLaeyer O wins","Tic TacToe", JOptionPane.INFORMATION_MESSAGE);
oCount++;
gameScore();
}
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 1200, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout(0, 0));
JPanel panel = new JPanel();
panel.setBorder(new LineBorder(new Color(0, 0, 0), 2));
frame.getContentPane().add(panel, BorderLayout.CENTER);
panel.setLayout(new GridLayout(3, 5, 2, 2));
JPanel panel_1 = new JPanel();
panel_1.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_1);
panel_1.setLayout(new BorderLayout(0, 0));
JButton btn1 = new JButton("");
btn1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn1.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn1.setForeground(Color.RED);
}
else
{
btn1.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn1.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_1.add(btn1, BorderLayout.CENTER);
JPanel panel_2 = new JPanel();
panel_2.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_2);
panel_2.setLayout(new BorderLayout(0, 0));
JButton btn2 = new JButton("");
btn2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn2.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn2.setForeground(Color.RED);
}
else
{
btn2.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn2.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_2.add(btn2, BorderLayout.CENTER);
JPanel panel_3 = new JPanel();
panel_3.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_3);
panel_3.setLayout(new BorderLayout(0, 0));
JButton btn3 = new JButton("");
btn3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn3.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn3.setForeground(Color.RED);
}
else
{
btn3.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn3.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_3.add(btn3, BorderLayout.CENTER);
JPanel panel_4 = new JPanel();
panel_4.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_4);
panel_4.setLayout(new BorderLayout(0, 0));
JLabel lblPlayerX = new JLabel("PLayer X");
lblPlayerX.setFont(new Font("Tahoma", Font.BOLD, 48));
panel_4.add(lblPlayerX, BorderLayout.CENTER);
JPanel panel_5 = new JPanel();
panel_5.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_5);
panel_5.setLayout(new BorderLayout(0, 0));
txtCountX = new JTextField();
txtCountX.setHorizontalAlignment(SwingConstants.CENTER);
txtCountX.setFont(new Font("Tahoma", Font.BOLD, 48));
txtCountX.setText("0");
panel_5.add(txtCountX, BorderLayout.CENTER);
txtCountX.setColumns(10);
JPanel panel_6 = new JPanel();
panel_6.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_6);
panel_6.setLayout(new BorderLayout(0, 0));
JButton btn4 = new JButton("");
btn4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn4.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn4.setForeground(Color.RED);
}
else
{
btn4.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn4.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_6.add(btn4, BorderLayout.CENTER);
JPanel panel_7 = new JPanel();
panel_7.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_7);
panel_7.setLayout(new BorderLayout(0, 0));
JButton btn5 = new JButton("");
btn5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn5.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn5.setForeground(Color.RED);
}
else
{
btn5.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn5.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_7.add(btn5, BorderLayout.CENTER);
JPanel panel_8 = new JPanel();
panel_8.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_8);
panel_8.setLayout(new BorderLayout(0, 0));
JButton btn6 = new JButton("");
btn6.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn6.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn6.setForeground(Color.RED);
}
else
{
btn6.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn6.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_8.add(btn6, BorderLayout.CENTER);
JPanel panel_9 = new JPanel();
panel_9.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_9);
panel_9.setLayout(new BorderLayout(0, 0));
JLabel lblPlayerO = new JLabel("PLayer O");
lblPlayerO.setFont(new Font("Tahoma", Font.BOLD, 48));
panel_9.add(lblPlayerO, BorderLayout.CENTER);
JPanel panel_10 = new JPanel();
panel_10.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_10);
panel_10.setLayout(new BorderLayout(0, 0));
txtCountO = new JTextField();
txtCountO.setHorizontalAlignment(SwingConstants.CENTER);
txtCountO.setFont(new Font("Tahoma", Font.BOLD, 48));
txtCountO.setText("0");
panel_10.add(txtCountO, BorderLayout.CENTER);
txtCountO.setColumns(10);
JPanel panel_11 = new JPanel();
panel_11.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_11);
panel_11.setLayout(new BorderLayout(0, 0));
JButton btn7 = new JButton("");
btn7.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn7.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn7.setForeground(Color.RED);
}
else
{
btn7.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn7.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_11.add(btn7, BorderLayout.CENTER);
JPanel panel_12 = new JPanel();
panel_12.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_12);
panel_12.setLayout(new BorderLayout(0, 0));
JButton btn8 = new JButton("");
btn8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn8.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn8.setForeground(Color.RED);
}
else
{
btn8.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn8.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_12.add(btn8, BorderLayout.CENTER);
JPanel panel_13 = new JPanel();
panel_13.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_13);
panel_13.setLayout(new BorderLayout(0, 0));
JButton btn9 = new JButton("");
btn9.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btn9.setText(startGame);
if(startGame.equalsIgnoreCase("X"))
{
btn9.setForeground(Color.RED);
}
else
{
btn9.setForeground(Color.BLUE);
}
choosePlayer();
WinningGame();
}
});
btn9.setFont(new Font("Tahoma", Font.BOLD, 96));
panel_13.add(btn9, BorderLayout.CENTER);
JPanel panel_14 = new JPanel();
panel_14.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_14);
panel_14.setLayout(new BorderLayout(0, 0));
JButton btnReset = new JButton("Reset");
btnReset.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
btn1.setText(null);
btn2.setText(null);
btn3.setText(null);
btn4.setText(null);
btn5.setText(null);
btn6.setText(null);
btn7.setText(null);
btn8.setText(null);
btn9.setText(null);
btn1.setBackground(Color.LIGHT_GRAY);
}
});
btnReset.setFont(new Font("Tahoma", Font.BOLD, 48));
panel_14.add(btnReset, BorderLayout.CENTER);
JPanel panel_15 = new JPanel();
panel_15.setBorder(new LineBorder(new Color(0, 0, 0), 2));
panel.add(panel_15);
panel_15.setLayout(new BorderLayout(0, 0));
JButton btnExit = new JButton("Exit");
btnExit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
frame = new JFrame("Exit");
if (JOptionPane.showConfirmDialog(frame, "Konfirmo nese do te
dalesh nga loja", "Tic Tac Toe",
JOptionPane.YES_NO_OPTION)==JOptionPane.YES_NO_OPTION){
System.exit(0);
}
}
});
btnExit.setFont(new Font("Tahoma", Font.BOLD, 48));
panel_15.add(btnExit, BorderLayout.CENTER);
}
}
答案 0 :(得分：0)
NullPointerException用WinningGame()方法加注。
因为字段btn1 - btn9是null。
实际问题在您的initialize()方法中。
您正在创建JButton btn1 = new JButton("")，但不要将其分配给字段，如下所示：
JButton btn1 = new JButton("");
this.btn1 = btn1; // this is the line you need to add for every button (btn1-btn9)
请不要忘记将类顶部的btn1 - btn9字段从JLabel替换为JButton。