在Java中，有没有一种方法可以将一组大小可变的按钮居中（使用Swing）？

Question

我一直在尝试制作这样的GUI：

然而，我遇到的困难是，我需要使按钮的文本可变-每个按钮应该提供不同的选项，可以在文本长度上有所不同。虽然这本身并不困难，但我尝试了无数不同的方法，但我无法让按钮居中，尽管它们的文本长度。无论我尝试什么，我总是有以下问题之一：

• 按钮不居中（左边有空间，但它们超过了右边的窗口）
• 由于某种原因，问题和Goodratio根据按钮大小更改位置

我不知道该怎么做。有没有人对做这件事的最佳方式有一些有用的直觉？非常感谢。

编辑：构造函数的代码（没有正确居中），我根据需要使用它设置组件：

    public ButtonPannel(Test test)
{
    super();

    op1Button = new JButton("Option 1");
    op2Button = new JButton("Option 2");
    op3Button = new JButton("Option 3");
    questionText = new JLabel("Question");
    rightAndWrongAmount = new JLabel("rightAndWrongAmount");

    GridBagLayout gridBagLayout = new GridBagLayout();
    gridBagLayout.columnWidths = new int[]{30, 331, 0};
    gridBagLayout.rowHeights = new int[]{16, 0, 134, 35, 16, 0};
    gridBagLayout.columnWeights = new double[]{0.0, 0.0, Double.MIN_VALUE};
    gridBagLayout.rowWeights = new double[]{0.0, 0.0, 1.0, 0.0, 0.0, Double.MIN_VALUE};
    setLayout(gridBagLayout);

    JPanel panel = new JPanel();
    FlowLayout flowLayout = (FlowLayout) panel.getLayout();

    op1Button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
        }
    });

    GridBagConstraints gbc_lblQuestion = new GridBagConstraints();
    gbc_lblQuestion.insets = new Insets(0, 0, 5, 0);
    gbc_lblQuestion.gridx = 1;
    gbc_lblQuestion.gridy = 1;
    add(questionText, gbc_lblQuestion);
    panel.add(op1Button);

    panel.add(op2Button);

    panel.add(op3Button);
    GridBagConstraints gbc_panel = new GridBagConstraints();
    gbc_panel.insets = new Insets(0, 0, 5, 0);
    gbc_panel.gridx = 1;
    gbc_panel.gridy = 3;
    add(panel, gbc_panel);

    GridBagConstraints gbc_lblNewLabel_1 = new GridBagConstraints();
    gbc_lblNewLabel_1.gridx = 1;
    gbc_lblNewLabel_1.gridy = 4;

    add(rightAndWrongAmount, gbc_lblNewLabel_1);

    op1Button.addActionListener(new InputHandler(test));
    op1Button.setActionCommand("1");
    op2Button.addActionListener(new InputHandler(test));
    op2Button.setActionCommand("2");
    op3Button.addActionListener(new InputHandler(test));
    op3Button.setActionCommand("3");

}

代码是使用WindowBuilder生成的。问题不在于代码，而在于使用哪种布局等等。

Answer 1

布局有点黑魔法和反复试验。很少会有一个单一的布局完全达到你想要的，所以你经常需要求助于复合布局（使用多个容器和布局）来得到你想要的...

因此，基本上，这是由一个面板组成的，另一个面板持有按钮（另一个面板充当“伪”内容以增加空间）

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

public class Test {

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

    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 TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            add(new JLabel("Question"), gbc);
            gbc.fill = GridBagConstraints.BOTH;
            gbc.weightx = 1;
            gbc.weighty = 1;
            // This is just to act as some psudo context
            add(new FillerPane(), gbc);
            gbc.fill = GridBagConstraints.NONE;
            gbc.weightx = 0;
            gbc.weighty = 0;
            add(makeButtonPane(), gbc);
            add(new JLabel("Goodratio"), gbc);
        }

        public JPanel makeButtonPane() { 
            JPanel panel = new JPanel(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.weightx = 1;
            panel.add(new JButton("Short"));
            panel.add(new JButton("Long, long, long and lobng"));
            panel.add(new JButton("In the middle"));
            return panel;
        }

    }

    public class FillerPane extends JPanel {

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

    }

}

“但是我希望按钮大小相同”我听到你问，当然，改变布局...

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

public class Test {

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

    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 TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            add(new JLabel("Question"), gbc);
            gbc.fill = GridBagConstraints.BOTH;
            gbc.weightx = 1;
            gbc.weighty = 1;
            // This is just to act as some psudo context
            add(new FillerPane(), gbc);
            gbc.fill = GridBagConstraints.NONE;
            gbc.weightx = 0;
            gbc.weighty = 0;
            add(makeButtonPane(), gbc);
            add(new JLabel("Goodratio"), gbc);
        }

        public JPanel makeButtonPane() { 
            JPanel panel = new JPanel(new GridLayout(1, 0));
            panel.add(new JButton("Short"));
            panel.add(new JButton("Long, long, long and lobng"));
            panel.add(new JButton("In the middle"));
            return panel;
        }

    }

    public class FillerPane extends JPanel {

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

    }

}

您必须查看布局，并考虑每个元素与其他元素之间的关系，以及您希望它们做什么，然后找到布局管理器，这些管理器将帮助您实现最终结果，并将它们结合在一起