JFrame 窗口不会显示

Question

（顺便说一句，我不是在寻找对代码本身的批评;我知道这是低效的，我只是在测试不同的东西，并想自己学习。我正在运行此代码，并且无法弄清楚为什么运行程序时我创建的JFrame没有出现。我在左上角看到程序名称（顺便说一下，我在mac上，所以这意味着程序正在运行）大约 3-5 秒，然后退出。它没有显示任何错误，它也没有显示JFrame。

import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TicTacToe extends JFrame
{ 
    JPanel board= new JPanel();
    static boolean isXTurn = true;
    static boolean isXTopLeft = false;
    static boolean isOTopLeft = false;
    static boolean isXTopCenter = false;
    static boolean isOTopCenter = false;
    static boolean isXTopRight = false;
    static boolean isOTopRight = false;
    static boolean isXCenterLeft = false;
    static boolean isOCenterLeft = false;
    static boolean isXCenterCenter = false;
    static boolean isOCenterCenter = false;
    static boolean isXCenterRight = false;
    static boolean isOCenterRight = false;
    static boolean isXBottomLeft = false;
    static boolean isOBottomLeft = false;
    static boolean isXBottomCenter = false;
    static boolean isOBottomCenter = false;
    static boolean isXBottomRight = false;
    static boolean isOBottomRight = false;
    String letterTopLeft;
    String letterTopCenter;
    String letterTopRight;
    String letterCenterLeft;
    String letterCenterCenter;
    String letterCenterRight;
    String letterBottomLeft;
    String letterBottomCenter;
    String letterBottomRight;
public TicTacToe()
{   
    JButton btnTopLeft = new JButton(letterTopLeft);
    JButton btnTopCenter = new JButton(letterTopCenter);
    JButton btnTopRight = new JButton(letterTopRight);
    JButton btnCenterLeft = new JButton(letterCenterLeft);
    JButton btnCenterCenter = new JButton(letterCenterCenter);
    JButton btnCenterRight = new JButton(letterCenterRight);
    JButton btnBottomLeft = new JButton(letterBottomLeft);
    JButton btnBottomCenter = new JButton(letterBottomCenter);
    JButton btnBottomRight = new JButton(letterBottomRight);
    this.setLayout(null);
    btnTopLeft.setLayout(null);
    btnTopCenter.setLayout(null);
    btnTopRight.setLayout(null);
    btnCenterLeft.setLayout(null);
    btnCenterCenter.setLayout(null);
    btnCenterRight.setLayout(null);
    btnBottomLeft.setLayout(null);
    btnBottomCenter.setLayout(null);
    btnBottomRight.setLayout(null);
    btnTopLeft.setBounds(0, 0, 100, 100);
    btnTopCenter.setBounds(100, 0, 100, 100);
    btnTopRight.setBounds(200, 0, 100, 100);
    btnCenterLeft.setBounds(0, 100, 100, 100);
    btnCenterCenter.setBounds(100, 100, 100, 100);
    btnCenterRight.setBounds(200, 100, 100, 100);
    btnBottomLeft.setBounds(0, 200, 100, 100);
    btnBottomCenter.setBounds(100, 200, 100, 100);
    btnBottomRight.setBounds(200, 200, 100, 100);
    board.setBounds(0, 0, 300, 300);
    btnTopLeft.setPreferredSize(new Dimension(100,100));
    board.add(btnTopLeft);
    board.add(btnTopCenter);
    board.add(btnTopRight);
    board.add(btnCenterLeft);
    board.add(btnCenterCenter);
    board.add(btnCenterRight);
    board.add(btnBottomLeft);
    board.add(btnBottomCenter);
    board.add(btnBottomRight);

    setSize(300, 300);
    setBackground(Color.gray);
    setTitle("Tic-Tac-Toe");
    setLocationRelativeTo(null);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}
public static void main(String[] theory)
{
}
 }

Answer 1

您有两个问题：

• 如您收到的评论中所述，您的 main 方法是空的。 遵循您在那里提出的建议。

• 董事会 JPanel 与 JFrame 无关。在构造函数方法的末尾添加以下行：

  this.add (board);
  

Answer 2

您的主方法应如下所示：

public static void main(String[] args) {
    new TicTacToe();
}

这将调用 TicTacToe 类的新实例，该实例将自动运行构造函数。

Answer 3

jframename  jf =  new jframename();
jf.setVisible(true);