GridBagLayout: equally distributed cells

Question

Is it possible to completely emulate the behavior of a GridLayout with the GridBagLayout manager?

Basically, I have a 8x8 grid in which each cell should have the same width and height. The GridLayout automatically did this. But I want to add another row and column to the grid which size is not the same as the other ones. That row/column should take up all the remaining space that might be left over (because the available size couldn't be equally distributed into 8 cells). Is that even possible, or do I – again – have to use a different layout manager?

edit

Here is a simple graphic of what I want to achieve, simplified to just 4 cells:

The colored cells are the ones I added to the actual grid (gray) which has cells with the same height and width x. So the grid's height and width is 4*x. I now want the additional cells to have the necessary width/height (minimumSize) plus the rest of the available width/height from the full size.

If the whole panel's size is changed, the gray grid cells should again take up as much as space as possible.

Answer 1

set weightx and weighty of GridBagConstraints of the fixed cells to 0 and the fill to NONE. For the floating cells set fill to BOTH, for the floating cells that should expand only horizontally set weightx to 1 and for the vertically expanding ones set weighty to 1.

The cells only expand if they have any content, so you need to fill it with something. I chose JLabels and set fixed dimensions for the labels in the fixed cells. On resize you need to recalculate the dimensions and call invalidate() to recalculate the layout.

Here is an example for a w x h grid:

import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class GridBag {
    public static void main(String[] args) {
        final JFrame f = new JFrame("Gridbag Test");
        final Container c = f.getContentPane();
        c.setLayout(new GridBagLayout());

        final Dimension dim = new Dimension(70, 70);
        final int w = 4;
        final int h = 4;
        final JLabel[] yfloating = new JLabel[w];
        final JLabel[] xfloating = new JLabel[h];
        final JLabel[][] fixed = new JLabel[w][h];

        // adding the vertically floating cells
        final GridBagConstraints gc = new GridBagConstraints();
        gc.fill = GridBagConstraints.BOTH;
        gc.weightx = 0.0;
        gc.weighty = 1.0;
        for(int i = 0; i < w; ++i) {
            yfloating[i] = new JLabel("floating " + i);
            yfloating[i].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            yfloating[i].setHorizontalTextPosition(JLabel.CENTER);
            yfloating[i].setVerticalTextPosition(JLabel.CENTER);
            gc.gridy = 0;
            gc.gridx = i+1;
            c.add(yfloating[i], gc);
        }

        // adding the horizontally floating cells
        gc.fill = GridBagConstraints.BOTH;
        gc.weightx = 1.0;
        gc.weighty = 0.0;
        for(int i = 0; i < w; ++i) {
            xfloating[i] = new JLabel("floating " + i);
            xfloating[i].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            xfloating[i].setHorizontalTextPosition(JLabel.CENTER);
            xfloating[i].setVerticalTextPosition(JLabel.CENTER);
            gc.gridy = i+1;
            gc.gridx = 0;
            c.add(xfloating[i], gc);
        }

        // adding the fixed cells
        gc.fill = GridBagConstraints.NONE;
        gc.weightx = 0.0;
        gc.weighty = 0.0;
        for(int i = 0; i < w; ++i) {
            for(int j = 0; j < h; ++j) {
                fixed[i][j] = new JLabel("fixed " + i);
                fixed[i][j].setBorder(BorderFactory.createLineBorder(Color.BLACK));
                fixed[i][j].setMaximumSize(dim);
                fixed[i][j].setMinimumSize(dim);
                fixed[i][j].setPreferredSize(dim);

                gc.gridx = i+1;
                gc.gridy = j+1;
                c.add(fixed[i][j], gc);
            }
        }

        c.addComponentListener(new ComponentAdapter() {
            @Override
            public void componentResized(ComponentEvent e) {
                final Component comp = e.getComponent();
                final int newSize = Math.min(comp.getHeight() / h, comp.getWidth() / w);
                final Dimension newDim = new Dimension(newSize, newSize);
                for(int i = 0; i < w; ++i) {
                    for(int j = 0; j < h; ++j) {
                        fixed[i][j].setMaximumSize(newDim);
                        fixed[i][j].setMinimumSize(newDim);
                        fixed[i][j].setPreferredSize(newDim);
                    }
                }
                comp.invalidate();
            }
        });

        f.pack();
        f.setVisible(true);
    }
}