Question

我正试图让垂直，顶部对齐的布局工作。这就是我所拥有的：

JPanel pane = new JPanel();
pane.setLayout(new BoxLayout(pane, BoxLayout.Y_AXIS));

MyImagePanel panelImage = new MyImagePanel();
panelImage.setSize(400, 400);

pane.add(new JComboBox());
pane.add(panelImage);
pane.add(new JButton("1"));
pane.add(new JButton("2"));
pane.add(new JButton("3"));

JFrame frame = new JFrame("Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 600);
frame.add(pane);
frame.pack();
frame.setVisible(true);

显示所有控件，但看起来在顶部和底部之间的运行时应用了填充，因此它们在某种程度上垂直居中。这就是我想要的：

-----------------------------------------------------
| ComboBox |                                        |
------------                                        |
|          |                                        |
| Image    |                                        |
|          |                                        |
------------                                        |
| Button 1 | Any additional space fills the right   |
------------                                        |
| Button 2 |                                        |
------------                                        |
| Button 3 |                                        |
------------                                        |
|                                                   |
|  Any additional space fills the bottom            |
|                                                   |
-----------------------------------------------------

如何让BoxLayout这样做？

由于

-------------------------更新--------------------- ----

能够使用这个：

Box vertical = Box.createVerticalBox();
frame.add(vertical, BorderLayout.NORTH);
vertical.add(new JComboBox());
vertical.add(new JButton("1"));  
...

得到我想要的东西。

Answer 1

更合适的LayoutManager是GridBagLayout，但还有其他选项：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test3 {

    protected static void initUI() {
        JPanel pane = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.fill = GridBagConstraints.NONE;
        gbc.weightx = 0.0;
        gbc.weighty = 0.0;
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        JPanel panelImage = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                g.setColor(Color.RED);
                g.fillRect(0, 0, 400, 400);
            }
        };
        panelImage.setPreferredSize(new Dimension(400, 400));

        pane.add(new JComboBox(), gbc);
        pane.add(panelImage, gbc);
        pane.add(new JButton("1"), gbc);
        pane.add(new JButton("2"), gbc);
        // We give all the extra horizontal and vertical space to the last component
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        pane.add(new JButton("3"), gbc);

        JFrame frame = new JFrame("Title");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(pane);
        frame.pack();
        frame.setVisible(true);

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                initUI();
            }
        });
    }
}

如何使BoxLayout垂直但儿童流动顶部对齐？

1 个答案: