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我正在製作一個tic tac腳趾遊戲，並且製作了gui並想運行它來測試它，但是出現了一些錯誤。我不知道爲什麼，並希望有人能夠解釋爲什麼這些錯誤即將出現，以及我應該如何解決這些錯誤。是我得到的錯誤如下所示：異常線程 「main」 顯示java.lang.NullPointerException 在TicTacToeSwing（TicTacToeSwing.java:84） 在TicTacToeSwing.main（TicTacToeSwing.java:180）Java - 井字遊戲Swing遊戲 - 錯誤
。這裏是我的代碼：（請注意：我還沒有完成計算，因爲我想讓gui先走）如果您知道我應該考慮採取更好的做法，請務必讓我知道。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
//井字
public class TicTacToeSwing extends JFrame
implements ActionListener {
//JButtons
//private JButton button1 = new JButton("");
private JButton jbtnTicTacToe1;
private JButton jbtnTicTacToe2;
private JButton jbtnTicTacToe3;
private JButton jbtnTicTacToe4;
private JButton jbtnTicTacToe5;
private JButton jbtnTicTacToe6;
private JButton jbtnTicTacToe7;
private JButton jbtnTicTacToe8;
private JButton jbtnTicTacToe9;
private JButton jbtnExit;
private JButton jbtnReset;
//JFrame window = new JFrame("Tic-Tac-Toe Swing ");
private JFrame window = new JFrame("Tic-Tac-Toe");
//labels
private JLabel jlblPlayerX = new JLabel ("X");
private JLabel jlblPlayerO = new JLabel ("O");
//text fields
JTextField jtfName = new JTextField(20);
private JTextField jtfPlayerX = new JTextField("X");
private JTextField jtfPlayerO = new JTextField("O");
//Panels
JPanel jpnlMain = new JPanel();
JPanel jpnlFamily = new JPanel();
JPanel jpnlNorth = new JPanel();
JPanel jpnlSouth = new JPanel();
JPanel jpnlCenter = new JPanel();
JPanel jpnlTop = new JPanel();
JPanel jpnlBottom = new JPanel();
//Class Constructor
public TicTacToeSwing() {
//Prepare JFrame/Window
super ("Tic Tac Toe");
setSize(400,400);
setTitle("Tic Tac Toe Swing");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Set the layouts for 3 rows and 3 columns
jpnlMain.setLayout(new BorderLayout(3,3));
jpnlCenter.setLayout(new GridLayout());
jpnlSouth.setLayout(new GridLayout());
jpnlTop.setLayout(new BorderLayout());
jpnlBottom.setLayout(new BorderLayout());
//Center Panel
jpnlCenter.add(jlblPlayerX);
jpnlCenter.add(jlblPlayerO);
//identify each JButton
jbtnReset.setActionCommand("Reset");
jbtnExit.setActionCommand("Exit");
//register JButton for event handling by using the THIS keyword - THIS class will handle the events
jbtnReset.addActionListener(this);
jbtnExit.addActionListener(this);
/*Add Buttons To The Window*/
window.add(jbtnTicTacToe1);
window.add(jbtnTicTacToe2);
window.add(jbtnTicTacToe3);
window.add(jbtnTicTacToe4);
window.add(jbtnTicTacToe5);
window.add(jbtnTicTacToe6);
window.add(jbtnTicTacToe7);
window.add(jbtnTicTacToe8);
window.add(jbtnTicTacToe9);
/*Add The Action Listener To The Buttons
button1.addActionListener(this);
button2.addActionListener(this);
button3.addActionListener(this);
button4.addActionListener(this);
button5.addActionListener(this);
button6.addActionListener(this);
button7.addActionListener(this);
button8.addActionListener(this);
button9.addActionListener(this);
*/
jbtnTicTacToe1.addActionListener(this);
jbtnTicTacToe2.addActionListener(this);
jbtnTicTacToe3.addActionListener(this);
jbtnTicTacToe4.addActionListener(this);
jbtnTicTacToe5.addActionListener(this);
jbtnTicTacToe6.addActionListener(this);
jbtnTicTacToe7.addActionListener(this);
jbtnTicTacToe8.addActionListener(this);
jbtnTicTacToe9.addActionListener(this);
//South Button Panel
jpnlSouth.add(jbtnReset);
jpnlSouth.add(jbtnExit);
/* Instantiate JButtons, put into a method for efficiency
jbtn1 = instantiateJButton("1", Color.PINK);
jbtn2 = instantiateJButton("2", Color.PINK);
jbtn3 = instantiateJButton("3", Color.PINK);
jbtn4 = instantiateJButton("4", Color.PINK);
jbtn5 = instantiateJButton("5", Color.PINK);
jbtn6 = instantiateJButton("6", Color.PINK);
jbtn7 = instantiateJButton("7", Color.PINK);
jbtn8 = instantiateJButton("8", Color.PINK);
jbtn9 = instantiateJButton("9", Color.PINK);
*/
//Finalize screen layout and publish to the display
jpnlMain.add(jpnlCenter, BorderLayout.NORTH);
jpnlMain.add(jpnlSouth, BorderLayout.CENTER);
//Prepare the container
Container ca = getContentPane();
ca.setBackground (Color.LIGHT_GRAY);
ca.add(jpnlMain);
setContentPane (ca);
setVisible(true);
//end constructor
}
//CLASS EVENT HANDLER
public void actionPerformed(java.awt.event.ActionEvent e)
{
//find out which JButton was pressed by using the Action Command
String sActionCommand = e.getActionCommand();
//EXIT JButton
if (sActionCommand == "Exit")
{
System.exit(0);
}
//RESET JButton
else if (sActionCommand == "Reset")
{
jtfPlayerX.setText("");
jtfPlayerO.setText("");
}
} //end ACTIONPERFORMED (java.awt.event.ActionEvent e)
/**
* @param args
*/
public static void main(String[] args) {
//EXECUTION STARTING POINT
TicTacToeSwing TicTacToeSwing = new TicTacToeSwing();
//TicTacToeSwing TicTacToeObject = new TicTacToeSwing();
}//end main(String[] args)
}//end TicTacToeSwing class
什麼行是被拋出的異常？ – 2013-04-22 15:55:36