JButtons消失了

Question

我是一个编程初学者，我试图创建一个计算器，我刚刚开始大约1到2个小时前，但我遇到了一个问题，我的所有jbutton都消失了。请帮助，我已经尝试了这么长时间，我只是不知道我的代码有什么问题。

公共类主{

static void gui() {

    JPanel p = new JPanel();

    JFrame f = new JFrame("Calculator");
    f.add(p);
    f.setLayout(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setTitle("YEET");
    f.pack();
    f.setSize(1930, 1090);

    JButton b0 = new JButton("0");
    JButton b1 = new JButton("1");
    JButton b2 = new JButton("2");
    JButton b3 = new JButton("3");
    JButton b4 = new JButton("4");
    JButton b5 = new JButton("5");
    JButton b6 = new JButton("6");
    JButton b7 = new JButton("7");
    JButton b8 = new JButton("8");
    JButton b9 = new JButton("9");

    b0.setBackground(new Color(156,207,245));

    b1.setBackground(new Color(156,207,245));
    b2.setBackground(new Color(156,207,245));
    b3.setBackground(new Color(156,207,245));

    b4.setBackground(new Color(156,207,245));
    b5.setBackground(new Color(156,207,245));
    b6.setBackground(new Color(156,207,245));

    b7.setBackground(new Color(156,207,245));
    b8.setBackground(new Color(156,207,245));
    b9.setBackground(new Color(156,207,245));


    p.setLayout(null);
    p.add(b1);

    p.add(b1);
    p.add(b2);
    p.add(b3);

    p.add(b4);
    p.add(b5);
    p.add(b6);

    p.add(b7);
    p.add(b8);
    p.add(b9);

    b0.setVisible(true);

    b1.setVisible(true);
    b2.setVisible(true);
    b3.setVisible(true);

    b4.setVisible(true);
    b5.setVisible(true);
    b6.setVisible(true);

    b7.setVisible(true);
    b8.setVisible(true);
    b9.setVisible(true);



    p.setVisible(true);

    f.setVisible((true));

}

public static void main(String[] args) {

            gui();

}

}`

Answer 1

null布局是个坏主意。“像素完美”布局是一种幻觉。花时间学习如何使用布局管理API。有关更多详细信息，请参见在容器中布局组件

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test {

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

    public Test() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private JButton b0 = new JButton("0");
        private JButton b1 = new JButton("1");
        private JButton b2 = new JButton("2");
        private JButton b3 = new JButton("3");
        private JButton b4 = new JButton("4");
        private JButton b5 = new JButton("5");
        private JButton b6 = new JButton("6");
        private JButton b7 = new JButton("7");
        private JButton b8 = new JButton("8");
        private JButton b9 = new JButton("9");

        public TestPane() {
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridy = 3;
            gbc.gridx = 0;
            gbc.weightx = 1;
            gbc.fill = gbc.BOTH;
            gbc.gridwidth = 3;

            add(b0, gbc);

            JButton[] buttons = new JButton[]{
                b7, b8, b9,
                b4, b5, b6,
                b1, b2, b3
            };
            int row = 0;
            int col = 0;
            gbc = new GridBagConstraints();
            gbc.fill = gbc.BOTH;
            gbc.weightx = 0.3;
            for (JButton btn : buttons) {
                gbc.gridx = col;
                gbc.gridy = row;
                add(btn, gbc);

                col += 1;
                if (col > 2) {
                    row++;
                    col = 0;
                }
            }
        }


    }

}

或者，如果GridBagLayout是少到多，则使用多个，例如BorderLayout和GridLayout

import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test {

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

    public Test() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private JButton b0 = new JButton("0");
        private JButton b1 = new JButton("1");
        private JButton b2 = new JButton("2");
        private JButton b3 = new JButton("3");
        private JButton b4 = new JButton("4");
        private JButton b5 = new JButton("5");
        private JButton b6 = new JButton("6");
        private JButton b7 = new JButton("7");
        private JButton b8 = new JButton("8");
        private JButton b9 = new JButton("9");

        public TestPane() {
            setLayout(new BorderLayout());

            add(b0, BorderLayout.SOUTH);

            JPanel innerPane = new JPanel(new GridLayout(3, 3));

            JButton[] buttons = new JButton[]{
                b7, b8, b9,
                b4, b5, b6,
                b1, b2, b3
            };
            for (JButton btn : buttons) {
                innerPane.add(btn);
            }

            add(innerPane);
        }

    }

}