GridBagLayout panels alignment

问题:

I have a little issue with the GridBag Layout Manager. I am trying to display 9 panels like this:

To do so, I separated the Grid like this:

For the panels 1 to 7 there is no problem, they show up just as I want. But the issue starts with the panels S8 and S9. As you can see, the S8 and S9 takes up half the frame, but I can't make it display like this. The S8 ends at the start of S4, and the S9 begins at the end of S4, I cannot handle the half space.

Only way I figured out is to put the S8 and S9 panel in another panel which takes all the frame width - but surely there must be a proper way to display these two panels without putting them in another panel!

Here is the code:

workzone.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.NORTHWEST;
c.fill = GridBagConstraints.BOTH;
c.weightx = 0.5;
c.weighty = 0.5;
c.insets = new Insets(0,0,0,0);

//S1
c.gridx = 0;
c.gridy = 0;
c.gridwidth = 2;
c.gridheight = 2;
workzone.add(S1, c);

//S2
c.gridx = 2;
c.gridy = 0;
c.gridwidth = 2;
c.gridheight = 1;
workzone.add(S2, c);

//S3
c.gridx = 2;
c.gridy = 1;
c.gridwidth = 2;
c.gridheight = 1;
workzone.add(S3, c);

//S4
c.gridx = 4;
c.gridy = 0;
c.gridwidth = 2;
c.gridheight = 2;
workzone.add(S4, c);

//S5
c.gridx = 7;
c.gridy = 0;
c.gridwidth = 1;
c.gridheight = 1;
workzone.add(S5, c);

//S6
c.gridx = 7;
c.gridy = 1;
c.gridwidth = 2;
c.gridheight = 1;
workzone.add(S6, c);

//S7
c.gridx = 8;
c.gridy = 0;
c.gridwidth = 2;
c.gridheight = 2;
workzone.add(S7, c);

//S8
c.gridx = 0;
c.gridy = 2;
c.gridwidth = 5;
c.gridheigth = 1;
workzone.add(S8, c);

//S9
c.gridx = 6;
c.gridy = 2;
c.gridwidth = 5;
c.gridheight = 1;
workzone.add(S9, c);

Any ideas and propositions are welcome !

回答1:

Good question. It took me little to crack it, but I got it. Normally, I would have put setions 1-7 in a top panel, and sections 8-9 in a bottom panel, but I liked the challange of 1 panel with GBL. [bored]

The problem is that section 4 (column indexes 4 and 5) is not well-defined for GBL, so section 8 doesn't know how far out to go to cover it's fifth column (index 4) so it then just stops after column index 3.

So, I added 2 zero-height spacers in the columns that make up section 4 and it worked. Comment out the 2 lines marked SPACERS to see what I mean:

EDIT: added fix suggested by @SheridanVespo

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class GridBagDemo2 implements Runnable
{
  private Color[] colors = {Color.BLACK, Color.BLUE, Color.CYAN, Color.GRAY,
                            Color.GREEN, Color.MAGENTA, Color.ORANGE,
                            Color.PINK, Color.RED, Color.YELLOW};

  private JPanel panel;
  private GridBagConstraints gbc;

  public static void main(String[] args)
  {
    SwingUtilities.invokeLater(new GridBagDemo2());
  }

  public void run()
  {
    panel = new JPanel(new GridBagLayout());
    gbc = new GridBagConstraints();

    add(0,0, 2,2, "1");
    add(2,0, 2,1, "2");
    add(2,1, 2,1, "3");
    add(4,0, 2,2, "4");
    add(6,0, 2,1, "5");
    add(6,1, 2,1, "6");
    add(8,0, 2,2, "7");
    add(0,2, 5,1, "8");
    add(5,2, 5,1, "9");

    // SPACERS: define the 2 columns that is section "4"
    add(4,3, 1,1, "");
    add(5,3, 1,1, "");

    JFrame frame = new JFrame("Grig Bag");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(panel);
    frame.pack();
    frame.setVisible(true);
  }

  private void add(int x, int y, int colspan, int rowspan, String name)
  {
    gbc.gridx = x;
    gbc.gridy = y;
    gbc.gridwidth = colspan;
    gbc.gridheight = rowspan;
    gbc.weightx = .1;
    gbc.weighty = .1;
    gbc.anchor = GridBagConstraints.CENTER;
    gbc.fill = GridBagConstraints.BOTH;

    // using another panel for illustrative purposes only
    JPanel p = new JPanel();

    if (!name.equals(""))
    {
      gbc.weightx = 1;                          // @SheridanVespo fix
      int index = Integer.parseInt(name);
      JLabel label = new JLabel("Panel " + name);
      p.add(label);
      p.setBackground(colors[index]);
      panel.add(p, gbc);
    }
    else
    {
      gbc.weightx = 0.5;                        // @SheridanVespo fix
      gbc.weighty = 0;  // don't allow the spacer to grow 
      gbc.fill = GridBagConstraints.NONE;
      panel.add(Box.createHorizontalGlue(), gbc);
    }
  }
}

回答2:

The accepted answer is appealing, but it causes section 4 to widen faster than the flanking panels as the frame is resized. This variation places panels 8 & 9 in a separate sub-panel of a BoxLayout.

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

/** @see https://stackoverflow.com/q/14755487/261156 */
public class GridBagDemo implements Runnable {

    private JPanel panel;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new GridBagDemo());
    }

    @Override
    public void run() {
        JFrame frame = new JFrame("GridBag");
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        panel = new JPanel(new GridBagLayout());
        add(1, 0, 0, 1, 2);
        add(2, 1, 0, 1, 1);
        add(3, 1, 1, 1, 1);
        add(4, 2, 0, 1, 2);
        add(5, 3, 0, 1, 1);
        add(6, 3, 1, 1, 1);
        add(7, 4, 0, 1, 2);
        frame.add(panel);
        panel = new JPanel(new GridBagLayout());
        add(8, 0, 0, 1, 1);
        add(9, 1, 0, 1, 1);
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private void add(int i, int x, int y, int w, int h) {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.gridwidth = w;
        gbc.gridheight = h;
        gbc.weightx = .1;
        gbc.weighty = .1;
        gbc.anchor = GridBagConstraints.CENTER;
        gbc.fill = GridBagConstraints.BOTH;
        JPanel p = new JPanel();
        p.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
        p.add(new JLabel("Panel " + i));
        p.setBackground(Color.getHSBColor((i - 1) / 9f, 0.75f, 0.95f));
        panel.add(p, gbc);
    }
}

回答3:

I never been a big fan of GridBagLayout. So for me I would break your GUI down into multiple panels and would probably use multiple GridLayout to achieve what you want. Something like:

JPanel top = new JPanel( new GridLayout(0, 5) );
top.add(s1);
JPanel s23 = new JPanel( new GridLayout(2, 0) );
s23.add(s2);
s23.add(s3);
top.add(s23);
...

JPanel bottom = new JPanel( new GridLayout(0, 2) );
bottom.add(s8);
bottom.add(s9);

JPanel main = new JPanel( appropriate layout manager );
main.add(top);
main.add(bottom);

回答4:

For the last two JPanel, I would suggest you to simply add them to a new JPanel with GridLayout and set this JPanel with the GridLayout on to the JPanel having the GridBagLayout. Please have a look at the code example, that resulted in actually the same output, as you were expecting :

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

/**
 * Created with IntelliJ IDEA.
 * User: Gagandeep Bali
 * Date: 2/7/13
 * Time: 10:34 PM
 * To change this template use File | Settings | File Templates.
 */
public class GridBagExample
{
    private JPanel contentPane, footerPanel;
    private JPanel s1, s2, s3, s4, s5, s6, s7, s8, s9;

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

        contentPane = new JPanel();
        contentPane.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        /*
         * Constraints for S1 JPanel.
         */
        gbc.anchor = GridBagConstraints.CENTER;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.gridwidth = 1;
        gbc.gridheight = 2;
        gbc.weightx = 0.2;
        gbc.weighty = 0.8;
        s1 = new JPanel(new GridBagLayout());
        s1.setOpaque(true);
        s1.setBackground(Color.BLUE);
        s1.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s1Label = new JLabel("S1", JLabel.CENTER);
        s1.add(s1Label);
        contentPane.add(s1, gbc);

        /*
         * Constraints for S2 JPanel.
         */
        gbc.weighty = 0.4;
        gbc.gridx = 1;
        gbc.gridheight = 1;
        s2 = new JPanel(new GridBagLayout());
        s2.setOpaque(true);
        s2.setBackground(Color.GREEN);
        s2.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s2Label = new JLabel("S2", JLabel.CENTER);
        s2.add(s2Label);
        contentPane.add(s2, gbc);

        /*
         * Constraints for S3 JPanel.
         */
        gbc.gridy = 1;
        s3 = new JPanel(new GridBagLayout());
        s3.setOpaque(true);
        s3.setBackground(Color.CYAN);
        s3.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s3Label = new JLabel("S3", JLabel.CENTER);
        s3.add(s3Label);
        contentPane.add(s3, gbc);

        /*
         * Constraints for S4 JPanel.
         */
        gbc.weighty = 0.8;
        gbc.gridx = 2;
        gbc.gridy = 0;
        gbc.gridheight = 2;
        s4 = new JPanel(new GridBagLayout());
        s4.setOpaque(true);
        s4.setBackground(Color.WHITE);
        s4.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s4Label = new JLabel("S4", JLabel.CENTER);
        s4.add(s4Label);
        contentPane.add(s4, gbc);

        /*
         * Constraints for S5 JPanel.
         */
        gbc.weighty = 0.4;
        gbc.gridx = 3;
        gbc.gridheight = 1;
        s5 = new JPanel(new GridBagLayout());
        s5.setOpaque(true);
        s5.setBackground(Color.RED);
        s5.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s5Label = new JLabel("S5", JLabel.CENTER);
        s5.add(s5Label);
        contentPane.add(s5, gbc);

        /*
         * Constraints for S6 JPanel.
         */
        gbc.gridy = 1;
        s6 = new JPanel(new GridBagLayout());
        s6.setOpaque(true);
        s6.setBackground(Color.MAGENTA);
        s6.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s6Label = new JLabel("S6", JLabel.CENTER);
        s6.add(s6Label);
        contentPane.add(s6, gbc);

        /*
         * Constraints for S7 JPanel.
         */
        gbc.gridheight = 2;
        gbc.weighty = 0.8;
        gbc.gridx = 4;
        gbc.gridy = 0;
        s7 = new JPanel(new GridBagLayout());
        s7.setOpaque(true);
        s7.setBackground(Color.ORANGE);
        s7.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s7Label = new JLabel("S7", JLabel.CENTER);
        s7.add(s7Label);
        contentPane.add(s7, gbc);

        footerPanel = new JPanel();
        footerPanel.setLayout(new GridLayout(1, 2, 5, 5));

        s8 = new JPanel(new GridBagLayout());
        s8.setOpaque(true);
        s8.setBackground(Color.PINK);
        s8.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s8Label = new JLabel("S8", JLabel.CENTER);
        s8.add(s8Label);
        footerPanel.add(s8);

        s9 = new JPanel(new GridBagLayout());
        s9.setOpaque(true);
        s9.setBackground(Color.YELLOW);
        s9.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 5));
        JLabel s9Label = new JLabel("S9", JLabel.CENTER);
        s9.add(s9Label);
        footerPanel.add(s9, gbc);

        /*
         * Constraints for Footer JPanel.
         */
        gbc.gridheight = 1;
        gbc.gridwidth = 5;
        gbc.weightx = 1.0;
        gbc.weighty = 0.2;
        gbc.gridx = 0;
        gbc.gridy = 2;
        contentPane.add(footerPanel, gbc);

        frame.setContentPane(contentPane);
        frame.pack();
        //frame.setSize(500, 500);
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

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

Here is the Output of the above code :

回答5:

Generally, I create and add the components of a GridBagLayout in Y, X position order. I don't know if this is required, but it makes it easier for me to diagnose problems.

Here's what I came up with for your grid.

Component   xPosition   yPosition   xWidth   yHeight
---------   ---------   ---------   ------   -------
S1              0           0          2        2
S2              2           0          2        1
S4              4           0          2        2
S5              6           0          2        1
S7              8           0          2        2
S8              0           2          5        1
S3              2           2          2        1
S9              5           2          5        1
S6              6           2          2        1

回答6:

For the S9 component, your code is

//S9
c.gridx = 6;
c.gridy = 2;
c.gridwidth = 5;
c.gridheight = 1;
workzone.add(S9, c);

Since the coordinate system begins at 0 rather than 1, I propose the code be

//S9
c.gridx = 5; // I changed this
c.gridy = 2;
c.gridwidth = 5;
c.gridheight = 1;
workzone.add(S9, c);

回答7:

I have tried using BorderLayout to check how it works. But just posting here .. :) This process uses multiple panels inside each other. You can try this approach if this example is comfortable.

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;


public class BorderAndGridBag {
    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                new GridWithBorder().createUI();
            }
        };

        EventQueue.invokeLater(r);
    }
}

class GridWithBorder {
    public void createUI() {
        JFrame frame = new JFrame();

        JPanel motherPanel = new JPanel(new BorderLayout());

        JPanel topPanel = new  JPanel();
        topPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel bottomPanel = new JPanel(new BorderLayout());
        bottomPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel topLeftPanel = new JPanel();
        topLeftPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel topRightPanel = new JPanel();
        topRightPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel topMiddlePanel = new JPanel();
        topMiddlePanel.add(new JLabel("Top Middle"));
        topMiddlePanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel bottomLeftPanel = new JPanel();
        bottomLeftPanel.add(new JLabel("Bottom Left"));
        bottomLeftPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel bottomRightPanel = new JPanel();
        bottomRightPanel.add(new JLabel("Bottom Right"));
        bottomRightPanel.setBorder(LineBorder.createBlackLineBorder());

        JPanel topLeftLeft = new JPanel();
        topLeftLeft.add(new JLabel("Top Left"));
        topLeftLeft.setBorder(LineBorder.createBlackLineBorder());


        JPanel topLeftRight = new JPanel(new BorderLayout());

        JPanel topLeftRightTop = new JPanel();
        topLeftRightTop.add(new JLabel("Top Left's Right Top"));
        topLeftRight.setBorder(LineBorder.createBlackLineBorder());

        JPanel topLeftRightBottom = new JPanel();
        topLeftRightBottom.add(new JLabel("Top Left's Right Bottom"));

        JPanel topRightLeft = new JPanel(new BorderLayout());
        topRightLeft.setBorder(LineBorder.createBlackLineBorder());

        JPanel topRightRight = new JPanel();
        topRightRight.add(new JLabel("Top Right Right"));
        topRightRight.setBorder(LineBorder.createBlackLineBorder());

        JPanel topRightLeftTop = new JPanel();
        topRightLeftTop.add(new JLabel("Top Right Left Top"));

        JPanel topRightLeftBottom = new JPanel();
        topRightLeftBottom.add(new JLabel("Top Right Left Bottom"));

        topLeftPanel.add(topLeftLeft, BorderLayout.WEST);

        // Top panel sub alignment.
        topLeftPanel.add(topLeftRight, BorderLayout.EAST);
        topLeftRight.add(topLeftRightTop, BorderLayout.NORTH);
        topLeftRight.add(topLeftRightBottom, BorderLayout.CENTER);


        topRightLeft.add(topRightLeftTop, BorderLayout.NORTH);
        topRightLeft.add(topRightLeftBottom, BorderLayout.SOUTH);
        topRightPanel.add(topRightLeft, BorderLayout.WEST);
        topRightPanel.add(topRightRight, BorderLayout.EAST);

        // Top Panel main alignment.
        topPanel.add(topLeftPanel, BorderLayout.WEST);
        topPanel.add(topMiddlePanel, BorderLayout.CENTER);
        topPanel.add(topRightPanel, BorderLayout.EAST);

        // Bottom Panel main alignment.
        bottomPanel.add(bottomLeftPanel, BorderLayout.WEST);
        bottomPanel.add(bottomRightPanel, BorderLayout.EAST);

        motherPanel.add(topPanel, BorderLayout.NORTH);
        motherPanel.add(bottomPanel, BorderLayout.CENTER);

        frame.add(motherPanel);
        frame.pack();
        frame.setTitle("Layout Manager");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}