当我更改 borderLayout 时，JPanels 不会四处移动

Question

我正在 Eclipse 中使用 swing 创建一个计算器程序。有几个按钮 0-9、+、-、*、/ 等。到目前为止，我已经创建了 3 个面板。我需要 5 个，我想把它们放在

clear /  -> Fifth panel
7 8 9 +  -> Fourth panel
4 5 6 -  -> Third panel
1 2 3 *  -> Second panel
0  =  .  -> First panel

但是按钮有重叠之类的，我无法将它们分开

我尝试了不同的 BorderLayout.____ 但他们仍然没有分开例如：

add(First, BorderLayout.BEFORE_FIRST_LINE);
add(Second, BorderLayout.EAST);
add(Third, BorderLayout.CENTER);

这是我的代码

import java.awt.*;
import javax.swing.*;   // swing offers many GUI components
import java.awt.event.*;

public class calculator
{
    public static void main (String [] args) 
    {           
        GUI myCalc = new GUI();
        myCalc.setTitle("Calculator");
        myCalc.setSize(350, 500);
        myCalc.setVisible(true);
        myCalc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }
}

class GUI extends JFrame implements ActionListener, MouseListener
{
    JPanel myFirstPanel;

    JButton zero, one, two, three, four, five, six, seven, eight, nine,
            dot, backspace, plus, minus, multiply, divide, clear;

    JLabel msgLabel;

    JTextField textBox;


    GUI()
    {
        super();

        JPanel First = new JPanel();
        JPanel Second = new JPanel();
        JPanel Third = new JPanel();

        one = new JButton("1");
        two = new JButton("2");
        three = new JButton("3");
        four = new JButton("4");
        five = new JButton("5");
        six = new JButton("6");
        seven = new JButton("7");
        eight = new JButton("8");
        nine = new JButton("9");

        First.add(one);
        First.add(two);
        First.add(three);
        Second.add(four);
        Second.add(five);
        Second.add(six);
        Third.add(seven);
        Third.add(eight);
        Third.add(nine);

        add(First, BorderLayout.BEFORE_FIRST_LINE);
        add(Second, BorderLayout.EAST);
        add(Third, BorderLayout.CENTER);

        add(First);
        add(Second);
        add(Third);
    }

    public void actionPerformed(ActionEvent e)
    {

    }

    public void mouseExited(MouseEvent me) // when mouse leaves
    {

    }

    public void mouseEntered(MouseEvent me) // when mouse enters
    {

    }

    public void mouseReleased(MouseEvent me) // when mouse is released after press
    {

    }

    public void mouseClicked(MouseEvent me) // when mouse is clicked
    {

    }

    public void mousePressed(MouseEvent me) // when mouse is pressed and held
    {

    }

}

我一直只收到 789 个按钮：/ 我对此很陌生，所以任何解释都会有所帮助。谢谢

Answer 1

作为 "general" 建议，您可以探索其他布局管理器。最终，您将到达想要探索的地步 GridBagLayout.

这是迄今为止最灵活的布局管理器，同时也是最复杂的。

您应该特别从 How to layout components within a container and How to use GridBagLayout 开始

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

public class Test {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Test();
    }

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

    public class TestPane extends JPanel {

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

            // First line
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.gridwidth = 3;
            gbc.fill = GridBagConstraints.BOTH;
            add(new JButton("Clear"), gbc);

            gbc.gridwidth = 1;
            gbc.gridx = 3;
            add(new JButton("/"), gbc);

            // Second line
            gbc.gridx = 0;
            gbc.gridy = 1;
            add(new JButton("7"), gbc);
            gbc.gridx++;
            add(new JButton("8"), gbc);
            gbc.gridx++;
            add(new JButton("9"), gbc);
            gbc.gridx++;
            add(new JButton("+"), gbc);

            // Third line
            gbc.gridx = 0;
            gbc.gridy = 2;
            add(new JButton("4"), gbc);
            gbc.gridx++;
            add(new JButton("5"), gbc);
            gbc.gridx++;
            add(new JButton("6"), gbc);
            gbc.gridx++;
            add(new JButton("-"), gbc);

            // Second line
            gbc.gridx = 0;
            gbc.gridy = 3;
            add(new JButton("1"), gbc);
            gbc.gridx++;
            add(new JButton("2"), gbc);
            gbc.gridx++;
            add(new JButton("3"), gbc);
            gbc.gridx++;
            add(new JButton("*"), gbc);

            // Last line
            gbc.gridx = 0;
            gbc.gridy = 4;
            add(new JButton("0"), gbc);
            gbc.gridx++;
            gbc.gridwidth = 2;
            add(new JButton("="), gbc);
            gbc.gridx += 2;
            gbc.gridwidth = 1;
            add(new JButton("."), gbc);
        }

    }

}

当我更改 borderLayout 时，JPanels 不会四处移动

JPanels arent moving around when I change the borderLayout

java

swing

jpanel

jframe

jbutton