java - GridBagLayout 无法正确布局

Question

我是 GridBagLayout 的新手，但我尝试使用我可以使用的标准约定找到哪个是在一张网格纸上画出我的想法，然后尝试将网格值转换成网格包...

我的目标是使布局如下所示:

目前看起来像这样:

知道为什么吗？

如果您想到左上角为 0,0 的网格，我正在寻找的确切尺寸对于

1. 目标图片面板中的红色:从第0列开始，跨越10列，高度为1行
2. 对于黑色面板:从第 0 列第 1 行开始，跨越 10 列，高度为 20 行
3. 对于蓝色面板:从第 0 列第 21 行开始，跨越 10 列，高度为 1
4. 对于绿色列:从第 10 列第 0 行开始，跨越 16 列，高度为 7
5. 对于紫色列:从第 10 列第 7 行开始，跨越 16 列，高度为 16

这是我的源代码:

GBC是一个扩展GridBagConstraints的辅助类，使用的构造函数是

GBC(int startingX,int startingY,int width,int height)

 /*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Demo extends JApplet
{

    JPanel panel1 = new JPanel();
    JPanel panel2 = new JPanel();
    JPanel panel3 = new JPanel();
    JPanel panel4 = new JPanel();
    JPanel panel5 = new JPanel();

    public void init()
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                initComponents();
            }
        });
    }

    public void initComponents()
    {
        //set the layout of the content pane to gridbag layout
        GridBagLayout gridBag = new GridBagLayout();
        getContentPane().setLayout(gridBag);

        Rectangle rect = getContentPane().getBounds();

        panel1.setBackground(Color.green);
        panel2.setBackground(Color.black);
        panel3.setBackground(Color.red);
        panel4.setBackground(Color.orange);
        panel5.setBackground(Color.yellow);

        add(panel4, new GBC(10, 0, 16, 7).setFill(GBC.BOTH).setWeight(1.0, 1.0));
        add(panel1, new GBC(0, 0, 10, 1).setFill(GBC.BOTH).setWeight(1.0, 1.0));
        add(panel3, new GBC(0, 21, 10, 1).setFill(GBC.BOTH).setWeight(1.0, 1.0));
        add(panel2, new GBC(0, 1, 10, 20).setFill(GBC.BOTH).setWeight(1.0, 1.0));
        add(panel5, new GBC(10, 7, 16, 16).setFill(GBC.BOTH).setWeight(1.0, 1.0));
    }
}

任何帮助将不胜感激(但请解释你的逻辑)

Answer 1

好吧，您可以使用 GridBagLayout 轻松完成此操作。

考虑到 contentPane 以 GridBagLayout 作为其布局，您现在可以将 JPanel 分为三个部分。单个左侧 JPanel(带有 GridBagLayout，其中将包含那些 RED、BLACK 和 BLUE JPanel)，右侧由两个 JPanel 组成，即 GREEN 和 MAGENTA。

 ------------------------
|  left   | green JPanel |
| JPanel  |______________|
|  with   |magenta Jpanel|
|3 JPanel |              |
|________________________|

现在左边的 JPanel 将放置 RED、BLACK 和 BLUE JPanel自身，使用 GridBagLayout 作为其 Layout Manager，RED 和 BLUE 具有 weighty = 0.1，并且 黑色 weighty = 0.8

查看示例代码:

import java.awt.*;
import javax.swing.*;

public class GridBagExample {
    private JPanel leftPanel;
    private JPanel redPanel;
    private JPanel blackPanel;
    private JPanel bluePanel;
    private JPanel greenPanel;
    private JPanel magentaPanel;

    private GridBagConstraints gbc;

    public GridBagExample() {
        gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.FIRST_LINE_START;
    }

    private void displayGUI() {
        JFrame frame = new JFrame("GridBagLayout Example");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel(new GridBagLayout());

        leftPanel = getPanel(Color.WHITE);
        leftPanel.setLayout(new GridBagLayout());
        redPanel = getPanel(Color.RED.darker());
        blackPanel = getPanel(Color.BLACK);
        bluePanel = getPanel(Color.CYAN.darker().darker());
        greenPanel = getPanel(Color.GREEN.darker().darker());
        magentaPanel = getPanel(Color.MAGENTA);
        /**
          * @param : 
          * leftPanel : JPanel (with GridBagLayout), on which
          *               all other components will be placed.
          * redPanel : JPanel, which will be added to the leftPanel
          * 0 : specifies the grid X, which in this case is 0
          * 0 : specifies the grid Y, which in this case is 0
          * 1 : specifies the width for this grid (cell), we keeping 
          *     this default as 1
          * 1 : specifies the height for this grid (cell), we keeping
          *     this default as 1
          * GridBagConstraints.BOTH : allows JPanel to expand in both
          *     directions as the containing container expands (in 
          *     this case redPanel will expand both HORIZONTALLY and
          *     VERTICALLY, as leftPanel will expand)
          * weightx : This is the actual width the redPanel will occupy
          *           relative to all other components on the leftPanel
          * weighty : This is the actual height the redPanel will occupy
          *           relative to all other components on the leftPanel
          */
        addComp(leftPanel, redPanel, 0, 0, 1, 1,
                        GridBagConstraints.BOTH, 1.0, 0.1);
        addComp(leftPanel, blackPanel, 0, 1, 1, 1,
                        GridBagConstraints.BOTH, 1.0, 0.8);
        addComp(leftPanel, bluePanel, 0, 2, 1, 1,
                        GridBagConstraints.BOTH, 1.0, 0.1);
        addComp(contentPane, leftPanel, 0, 0, 1, 2,
                        GridBagConstraints.BOTH, 0.5, 1.0);
        addComp(contentPane, greenPanel, 1, 0, 1, 1,
                        GridBagConstraints.BOTH, 0.5, 0.3);
        addComp(contentPane, magentaPanel, 1, 1, 1, 1,
                        GridBagConstraints.BOTH, 0.5, 0.7);

        frame.setContentPane(contentPane);
        /*
         * Once you will add components to these
         * JPanels, then use pack(), instead of
         * setSize(). The use of the latter is 
         * just for illustration purpose only
         */
        //frame.pack();
        frame.setSize(300, 300);
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private void addComp(JPanel panel, JComponent comp,
                            int x, int y, int width, int height,
                            int fill, double weightx, double weighty) {
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.gridwidth = width;
        gbc.gridheight = height;
        gbc.fill = fill;
        gbc.weightx = weightx;
        gbc.weighty = weighty;

        panel.add(comp, gbc);
    }

    private JPanel getPanel(Color backColor) {
        JPanel panel = new JPanel();
        panel.setOpaque(true);
        panel.setBackground(backColor);

        return panel;
    }

    public static void main(String[] args) {
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                new GridBagExample().displayGUI();
            }
        };
        EventQueue.invokeLater(runnable);
    }
}

这是相同的输出: