有没有办法强制GridLayout留下空单元格？

Question

我有一个JTabbedPane,其中2个JPanels设置为GridLayout(13,11).第一个JPanel有足够的单元格填充它离开空单元格.

第二个JPanel填充的单元格明显更少,这导致每个按钮被拉伸以填满整行.

有没有办法让GridLayout尊重空单元格,所以两个JPanels中的按钮大小相同？

Answer 1

使用嵌套布局来获得所需的结果.某些布局遵循组件的首选大小,而有些则不支持.GridLayout是其中之一.看看这个答案,看看哪一个做,哪个不做.

例如,你可以窝在13个按钮在GridLayout 嵌套在另一个JPanel用FlowLayout

JPanel p1 = new JPanel(new FlowLayout(FlowLayout.LEADING));
JPanel p2 = new JPanel(new GridLayout(13, 1));
for (int i = 0; i < 13; i++) {
    p2.add(new JButton("Button " + i));
}
p1.add(p2);

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

public class Test6 {

    public Test6() {
        JPanel p1 = new JPanel(new FlowLayout(FlowLayout.LEADING));
        JPanel p2 = new JPanel(new GridLayout(13, 1));
        for (int i = 0; i < 13; i++) {
            p2.add(new JButton("Button " + i));
        }
        p1.add(p2);

        JFrame frame = new JFrame("Test Card");
        frame.add(p1);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
        frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                Test6 test = new Test6();
            }
        });
    }
}

Answer 2

有没有办法让GridLayout尊重空单元格,所以两个JPanels中的按钮大小相同？

当然可以使用没有文字GridLayout的空白方块"填充" JLabel它.

EG这是两个网格布局,都填充到3行.

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.border.LineBorder;

class FillGridLayout {

    public static final JComponent getPaddedGrid(
            ArrayList<BufferedImage> images, int width, int height) {
        JPanel p = new JPanel(new GridLayout(height, width, 2, 2));
        p.setBorder(new LineBorder(Color.RED));
        int count = 0;
        for (BufferedImage bi : images) {
            p.add(new JButton(new ImageIcon(bi)));
            count++;
        }
        for (int ii=count; ii<width*height; ii++ ) {
            // add invisible component
            p.add(new JLabel());
        }
        return p;
    }

    public static void main(String[] args) {
        final ArrayList<BufferedImage> images = new ArrayList<BufferedImage>();
        int s = 16;
        for (int ii = s/4; ii < s; ii+=s/4) {
            images.add(new BufferedImage(ii, s, BufferedImage.TYPE_INT_RGB));
            images.add(new BufferedImage(s, ii, BufferedImage.TYPE_INT_RGB));
        }
        Runnable r = new Runnable() {
            @Override
            public void run() {
                JPanel gui = new JPanel(new BorderLayout(3,3));
                gui.add(getPaddedGrid(images, 3, 3), BorderLayout.LINE_START);
                gui.add(getPaddedGrid(images, 4, 3), BorderLayout.LINE_END);

                JOptionPane.showMessageDialog(null, gui);
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency
        SwingUtilities.invokeLater(r);
    }
}

Answer 3

将空 JLabel 添加到空单元格

content.add(new JLabel(""));