JButtons没有出现在JFrame上的JPanel上

Question

我试图在3x3网格中显示9个3x3网格。但是没有按钮出现。我不得不创建所有单独的按钮，我不知道如果我的代码中有明显错误，他们是否占用了很多空间。感谢您的任何意见！

 public class BoardGui extends JFrame{
    private JPanel center;
    private JPanel grid00;
    private JPanel grid01;
    private JPanel grid02;
    private JPanel grid10;
    private JPanel grid11;
    private JPanel grid12;
    private JPanel grid20;
    private JPanel grid21;
    private JPanel grid22;



    private JButton sq0000,sq0100,sq0200,sq1000,sq1100,
        sq1200,sq2000,sq2100,sq2200;
        private JButton sq0001,sq0101,sq0201,sq1001,sq1101,sq1201,sq2001
        ,sq2101,sq2201;
        private JButton sq0002,sq0102,sq0202,sq1002,sq1102,sq1202
        ,sq2002,sq2102,sq2202;
        private JButton sq0010,sq0110,sq0210,sq1010,sq1110,sq1210,
        sq2010,sq2110,sq2210;
        private JButton sq0011,sq0111,sq0211,sq1011,sq1111,
        sq1211,sq2011,sq2111,sq2211;
        private JButton sq0012,sq0112,sq0212,sq1012,sq1112,sq1212,
        sq2012,sq2112,sq2212;
        private JButton sq0020,sq0120,sq0220,sq1020,sq1120,sq1220,
        sq2020,sq2120,sq2220;
        private JButton sq0021,sq0121,sq0221,sq1021,sq1121,
        sq1221,sq2021,sq2121,sq2221;
        private JButton sq0022,sq0122,sq0222,sq1022,sq1122,sq1222,
        sq2022,sq2122,sq2222;

        public void Board(){

            setLayout(new BorderLayout());

            center.setLayout(new GridLayout(3,3));

            grid00 = new JPanel();
            grid01 = new JPanel();
            grid02 = new JPanel();
            grid10 = new JPanel();
            grid11 = new JPanel();
            grid12 = new JPanel();
            grid20 = new JPanel();
            grid21 = new JPanel();
            grid22 = new JPanel();

            grid00.setLayout(new GridLayout(3,3));
            grid01.setLayout(new GridLayout(3,3));
            grid02.setLayout(new GridLayout(3,3));
            grid10.setLayout(new GridLayout(3,3));
            grid11.setLayout(new GridLayout(3,3));
            grid12.setLayout(new GridLayout(3,3));
            grid20.setLayout(new GridLayout(3,3));
            grid21.setLayout(new GridLayout(3,3));
            grid22.setLayout(new GridLayout(3,3));

            sq0000 = new JButton();
            sq0001 = new JButton();
            sq0002 = new JButton();
            sq0010 = new JButton();
            sq0011 = new JButton();
            sq0012 = new JButton();
            sq0020 = new JButton();
            sq0021 = new JButton();
            sq0022 = new JButton();

            sq0100 = new JButton();
            sq0101 = new JButton();
            sq0102 = new JButton();
            sq0110 = new JButton();
            sq0111 = new JButton();
            sq0112 = new JButton();
            sq0120 = new JButton();
            sq0121 = new JButton();
            sq0122 = new JButton();

            sq0200 = new JButton();
            sq0201 = new JButton();
            sq0202 = new JButton();
            sq0210 = new JButton();
            sq0211 = new JButton();
            sq0212 = new JButton();
            sq0220 = new JButton();
            sq0221 = new JButton();
            sq0222 = new JButton();

            sq1000 = new JButton();
            sq1001 = new JButton();
            sq1002 = new JButton();
            sq1010 = new JButton();
            sq1011 = new JButton();
            sq1012 = new JButton();
            sq1020 = new JButton();
            sq1021 = new JButton();
            sq1022 = new JButton();

            sq1100 = new JButton();
            sq1101 = new JButton();
            sq1102 = new JButton();
            sq1110 = new JButton();
            sq1111 = new JButton();
            sq1112 = new JButton();
            sq1120 = new JButton();
            sq1121 = new JButton();
            sq1122 = new JButton();

            sq1200 = new JButton();
            sq1201 = new JButton();
            sq1202 = new JButton();
            sq1210 = new JButton();
            sq1211 = new JButton();
            sq1212 = new JButton();
            sq1220 = new JButton();
            sq1221 = new JButton();
            sq1222 = new JButton();

            sq2000 = new JButton();
            sq2001 = new JButton();
            sq2002 = new JButton();
            sq2010 = new JButton();
            sq2011 = new JButton();
            sq2012 = new JButton();
            sq2020 = new JButton();
            sq2021 = new JButton();
            sq2022 = new JButton();

            sq2100 = new JButton();
            sq2101 = new JButton();
            sq2102 = new JButton();
            sq2110 = new JButton();
            sq2111 = new JButton();
            sq2112 = new JButton();
            sq2120 = new JButton();
            sq2121 = new JButton();
            sq2122 = new JButton();

            sq2200 = new JButton();
            sq2201 = new JButton();
            sq2202 = new JButton();
            sq2210 = new JButton();
            sq2211 = new JButton();
            sq2212 = new JButton();
            sq2220 = new JButton();
            sq2221 = new JButton();
            sq2222 = new JButton();

            grid00.add(sq0000);
            grid00.add(sq0001);
            grid00.add(sq0002);
            grid00.add(sq0010);
            grid00.add(sq0011);
            grid00.add(sq0012);
            grid00.add(sq0020);
            grid00.add(sq0021);
            grid00.add(sq0022);

            grid01.add(sq0100);
            grid01.add(sq0101);
            grid01.add(sq0102);
            grid01.add(sq0110);
            grid01.add(sq0111);
            grid01.add(sq0112);
            grid01.add(sq0120);
            grid01.add(sq0121);
            grid01.add(sq0122);

            grid02.add(sq0200);
            grid02.add(sq0201);
            grid02.add(sq0202);
            grid02.add(sq0210);
            grid02.add(sq0211);
            grid02.add(sq0212);
            grid02.add(sq0220);
            grid02.add(sq0221);
            grid02.add(sq0222);

            grid10.add(sq1000);
            grid10.add(sq1001);
            grid10.add(sq1002);
            grid10.add(sq1010);
            grid10.add(sq1011);
            grid10.add(sq1012);
            grid10.add(sq1020);
            grid10.add(sq1021);
            grid10.add(sq1022);

            grid11.add(sq1100);
            grid11.add(sq1101);
            grid11.add(sq1102);
            grid11.add(sq1110);
            grid11.add(sq1111);
            grid11.add(sq1112);
            grid11.add(sq1120);
            grid11.add(sq1121);
            grid11.add(sq1122);

            grid12.add(sq1200);
            grid12.add(sq1201);
            grid12.add(sq1202);
            grid12.add(sq1210);
            grid12.add(sq1211);
            grid12.add(sq1212);
            grid12.add(sq1220);
            grid12.add(sq1221);
            grid12.add(sq1222);

            grid20.add(sq2000);
            grid20.add(sq2001);
            grid20.add(sq2002);
            grid20.add(sq2010);
            grid20.add(sq2011);
            grid20.add(sq2012);
            grid20.add(sq2020);
            grid20.add(sq2021);
            grid20.add(sq2022);

            grid21.add(sq2100);
            grid21.add(sq2101);
            grid21.add(sq2102);
            grid21.add(sq2110);
            grid21.add(sq2111);
            grid21.add(sq2112);
            grid21.add(sq2120);
            grid21.add(sq2121);
            grid21.add(sq2122);

            grid22.add(sq2200);
            grid22.add(sq2201);
            grid22.add(sq2202);
            grid22.add(sq2210);
            grid22.add(sq2211);
            grid22.add(sq2212);
            grid22.add(sq2220);
            grid22.add(sq2221);
            grid22.add(sq2222);

            center.add(grid00);
            center.add(grid01);
            center.add(grid02);
            center.add(grid10);
            center.add(grid11);
            center.add(grid12);
            center.add(grid20);
            center.add(grid21);
            center.add(grid22);

            add(center, BorderLayout.CENTER);

        }

        public static void main(String[] args) {
            BoardGui gui = new BoardGui();
            gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            gui.setSize(700, 700);
            gui.setResizable(true);
            gui.setVisible(true);
            gui.setTitle("Tic Tac Toe Extreme");
        }

    }

Answer 1

到目前为止，通过查看您的代码，它将生成NullPointerException，因为中心永远不会被初始化...至于这是否是您的实际问题，我只能猜测

话虽如此，您需要学习如何使用数组并将代码分解为可管理的块。

有很多重复，你会发疯，不要以某种方式重复使用它，例如......

您可以创建一个自定义JPanel，它的唯一责任是显示3x3网格按钮......

public class ButtonPane extends JPanel {

    private JButton[][] btns;

    public ButtonPane() {
        setLayout(new GridLayout(3, 3));
        btns = new JButton[3][3];
        for (int row = 0; row < 3; row++) {
            for (int col = 0; col < 3; col++) {
                btns[row][col] = new JButton(row + "x" + col);
                add(btns[row][col]);
            }
        }
    }

    public JButton getButtonAt(int row, int col) {
        return btns[row][col];
    }

}

然后你可以创建另一个自定义面板，它的职责是显示这些按钮面板的3x3网格......

public class ContentPane extends JPanel {

    private ButtonPane[][] buttonPanels;

    public ContentPane() {
        setLayout(new GridLayout(3, 3));
        buttonPanels = new ButtonPane[3][3];
        for (int row = 0; row < 3; row++) {
            for (int col = 0; col < 3; col++) {
                buttonPanels[row][col] = new ButtonPane();
                add(buttonPanels[row][col]);
            }
        }
    }

    public ButtonPane getButtonPaneAt(int row, int col) {
        return buttonPanels[row][col];
    }

}

然后把它们放在一个框架或其他容器上......

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test{

    public static void main(String[] args) {
        new JavaApplication834();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new ContentPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class ContentPane extends JPanel {

        private ButtonPane[][] buttonPanels;

        public ContentPane() {
            setLayout(new GridLayout(3, 3));
            buttonPanels = new ButtonPane[3][3];
            for (int row = 0; row < 3; row++) {
                for (int col = 0; col < 3; col++) {
                    buttonPanels[row][col] = new ButtonPane();
                    add(buttonPanels[row][col]);
                }
            }
        }

        public ButtonPane getButtonPaneAt(int row, int col) {
            return buttonPanels[row][col];
        }

    }

    public class ButtonPane extends JPanel {

        private JButton[][] btns;

        public ButtonPane() {
            setLayout(new GridLayout(3, 3));
            btns = new JButton[3][3];
            for (int row = 0; row < 3; row++) {
                for (int col = 0; col < 3; col++) {
                    btns[row][col] = new JButton(row + "x" + col);
                    add(btns[row][col]);
                }
            }
        }

        public JButton getButtonAt(int row, int col) {
            return btns[row][col];
        }

    }

}

请记住，Java是一种面向对象的语言，它是生成可重用块的目标之一......