Here is a pretty simple layout (code included) where non-uniform column sizes could improve packing.
Is there a way, using a single GridBagLayout, to get the components to fit together nicely?
I thought that using a width of 3 for the top two components, then a width of 5 & 1 for the next two rows would influence the alignment, but I cannot get it to stay flush. My current solution (not included) is to create a sub panel with the red and green panels.
import javax.swing.*;
import java.awt.*;
public class GridBagWrong{
public static void main(String[] args){
JPanel content = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
//create five panels to layout.
JPanel a = new JPanel();
a.setPreferredSize( new Dimension(300, 30) );
a.setBorder( BorderFactory.createLineBorder(Color.BLUE) );
JPanel b = new JPanel();
b.setPreferredSize( new Dimension(300, 30) );
b.setBorder( BorderFactory.createLineBorder(Color.BLUE) );
JPanel c = new JPanel();
c.setPreferredSize( new Dimension(500, 30) );
c.setBorder( BorderFactory.createLineBorder(Color.GREEN) );
JPanel d = new JPanel();
d.setPreferredSize( new Dimension(500, 30) );
d.setBorder( BorderFactory.createLineBorder(Color.GREEN) );
JPanel e = new JPanel();
e.setPreferredSize( new Dimension(100, 60) );
e.setBorder( BorderFactory.createLineBorder(Color.RED) );
//place them in a gridbaglayout.
gbc.gridwidth = 3;
content.add(a, gbc);
gbc.gridx = 3;
content.add(b, gbc);
gbc.gridx = 0;
gbc.gridy = 1;
gbc.gridwidth = 5;
content.add(c, gbc);
gbc.gridy = 2;
content.add(d, gbc);
gbc.gridy = 1;
gbc.gridx = 5;
gbc.gridheight = 2;
gbc.gridwidth = 1;
content.add(e, gbc);
JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setContentPane( content );
frame.pack();
frame.setVisible(true);
}
}
CodePudding user response：
Following up on my comment from above you can use:
//JPanel content = new JPanel(new GridBagLayout());
GridBagLayout gbl = new GridBagLayout();
int[] columns = new int[6];
Arrays.fill(columns, 100);
gbl.columnWidths = columns;
JPanel content = new JPanel(gbl);
The above code states each of the 6 columns will have a minimum width of 100.
If a component is added to a column with gridwidth = 1, then the preferred size of that component will be used as the width of the column.
So now when you specify gridwidth = 3 it has a meaning because the layout can use either the width of a component added to the columnn or the minimum width to determine the actual size of the component.
CodePudding user response：
For some reason GridBagLayout is adding addition space to it's calculations, but I'm not sure why. At first I thought it was the LineBorder, but when I modified your code to remove the border, it still didn't work...
I don't know where the extra spacing on the right is coming from (it's probably really obvious, but I can't see it)
Sooo, this is one of those moments where I "flip the table" and "rage quite" and instead, "hack it"
Since there seems to be a disconnect between the first and second row, for some reason, I combined the two panels from the first row into a single panel and got rid of all the gridwidths (more or less)
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
//create five panels to layout.
JPanel a = new LayoutPane();
a.setForeground(Color.BLUE);
a.setPreferredSize(new Dimension(300, 30));
JPanel b = new LayoutPane();
b.setPreferredSize(new Dimension(300, 30));
b.setForeground(Color.BLUE);
JPanel c = new LayoutPane();
c.setPreferredSize(new Dimension(500, 30));
c.setForeground(Color.GREEN);
JPanel d = new LayoutPane();
d.setPreferredSize(new Dimension(500, 30));
d.setForeground(Color.GREEN);
JPanel e = new LayoutPane();
e.setPreferredSize(new Dimension(100, 60));
e.setForeground(Color.RED);
JPanel topPane = new JPanel(new GridBagLayout());
//place them in a gridbaglayout.
gbc.gridx = 0;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPane.add(a, gbc);
gbc.gridx ;
topPane.add(b, gbc);
gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.gridx = 0;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(topPane, gbc);
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 1;
gbc.anchor = GridBagConstraints.WEST;
add(c, gbc);
gbc.gridy = 2;
add(d, gbc);
gbc = new GridBagConstraints();
gbc.gridy = 1;
gbc.gridx ;
gbc.gridheight = 2;
gbc.anchor = GridBagConstraints.EAST;
add(e, gbc);
}
}
public class LayoutPane extends JPanel {
public LayoutPane() {
setOpaque(false);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(getForeground());
g2d.drawRect(0, 0, getWidth() - 1, getHeight() - 1);
String text = getWidth() "x" getHeight();
FontMetrics fm = g2d.getFontMetrics();
int x = (getWidth() - fm.stringWidth(text)) / 2;
int y = ((getHeight() - fm.getHeight()) / 2) fm.getAscent();
g2d.drawString(text, x, y);
g2d.dispose();
}
}
}