GridBagLayout - forcing all components to stay on top

I'm experimenting with the standard Java Layouts, and I'm really sorry to say that I'd like to try custom ones, but can't.

So I'm going through the not-so-pleasing experience of trying to get GridBagLayout to work as I want.

I modded the Sun example to fit my needs, but I can't get the buttons to stay together on top of the Layout.
I wonder if that's even possible without setting too many hand-picked constraints and/or making the buttons resize
vertically (they would become too tall).

This is what happens when I resize the window. I'd like to see the red space go away, and the buttons to keep their vertical size.

http://img823.imageshack.us/img823/3...ginehgb.th.png

Here's the code. I set all the weights to 1.0 because I didn't want to bother with that mess.

Code:

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

public class GridBagLayoutDemo {
        final static boolean shouldFill = true;
        final static boolean shouldWeightX = true;
        final static boolean RIGHT_TO_LEFT = false;

        public static void addComponentsToPane(Container pane) {
                if (RIGHT_TO_LEFT) {
                        pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
                }

                JButton button; // temp
                pane.setLayout(new GridBagLayout());
                GridBagConstraints c = new GridBagConstraints();

                if (shouldFill) {
                        // natural height, maximum width
                        c.fill = GridBagConstraints.HORIZONTAL;
                }

                button = new JButton("Button 1");
                if (shouldWeightX) {
                        c.weightx = 1.0;
                        c.weighty = 1.0; // request any extra vertical space
                        c.anchor = GridBagConstraints.PAGE_START; // top of space
                }
                c.fill = GridBagConstraints.HORIZONTAL;
                c.gridx = 0;
                c.gridy = 0;
                pane.add(button, c);

                button = new JButton("Button 2");
                c.fill = GridBagConstraints.HORIZONTAL;
                c.weightx = 1.0;
                c.weighty = 1.0; // request any extra vertical space
                c.anchor = GridBagConstraints.PAGE_START; // top of space
                c.gridx = 1;
                c.gridy = 0;
                pane.add(button, c);

                button = new JButton("Button 3");
                c.fill = GridBagConstraints.HORIZONTAL;
                c.weightx = 1.0;
                c.weighty = 1.0; // request any extra vertical space
                c.anchor = GridBagConstraints.PAGE_START; // top of space
                c.gridx = 2;
                c.gridy = 0;
                pane.add(button, c);

                button = new JButton("Long-Named Button 4");
                c.fill = GridBagConstraints.HORIZONTAL;
                c.ipady = 40; // make this component tall
                c.weightx = 1.0;
                c.weighty = 1.0; // request any extra vertical space
                c.anchor = GridBagConstraints.PAGE_START; // top of space
                c.gridwidth = 3;
                c.gridx = 0;
                c.gridy = 1;
                pane.add(button, c);
        }

        /**
        * Create the GUI and show it. For thread safety, this method should be
        * invoked from the event-dispatching thread.
        */
        private static void createAndShowGUI() {
                // Create and set up the window.
                JFrame frame = new JFrame("GridBagLayoutDemo");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                // Set up the content pane.
                addComponentsToPane(frame.getContentPane());

                // Display the window.
                frame.pack();
                frame.setVisible(true);
        }

        public static void main(String[] args) {
                // Schedule a job for the event-dispatching thread:
                // creating and showing this application's GUI.
                javax.swing.SwingUtilities.invokeLater(new Runnable() {
                        public void run() {
                                createAndShowGUI();
                        }
                });
        }
}

---

I think I understand what you want, and if so, the solution is to nest layouts. Place your components into a JPanel that uses GridBagLayout, and then place that component into a container that uses BorderLayout in the BorderLayout.PAGE_START or BorderLayout.NORTH position (same thing). It just so happens that the JFrame's contentPane uses BorderLayout by default, so you can do it like so:

Code:

---

import java.awt.*;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class GridBagLayoutDemo2 {
  final static boolean shouldFill = true;
  final static boolean shouldWeightX = true;
  final static boolean RIGHT_TO_LEFT = false;

  public static void addComponentsToPane(Container pane) {

      // create a new JPanel that will use GridBagLayout
      JPanel gridBagPanel = new JPanel();
      if (RIGHT_TO_LEFT) {
        gridBagPanel.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
      }

      JButton button;
      gridBagPanel.setLayout(new GridBagLayout());
      GridBagConstraints c = new GridBagConstraints();

      if (shouldFill) {

        c.fill = GridBagConstraints.HORIZONTAL;
      }

      button = new JButton("Button 1");
      if (shouldWeightX) {
        c.weightx = 1.0;
        c.weighty = 1.0;
        c.anchor = GridBagConstraints.PAGE_START;
      }
      c.fill = GridBagConstraints.HORIZONTAL;
      c.gridx = 0;
      c.gridy = 0;
      gridBagPanel.add(button, c);

      button = new JButton("Button 2");
      c.fill = GridBagConstraints.HORIZONTAL;
      c.weightx = 1.0;
      c.weighty = 1.0;
      c.anchor = GridBagConstraints.PAGE_START;
      c.gridx = 1;
      c.gridy = 0;
      gridBagPanel.add(button, c);

      button = new JButton("Button 3");
      c.fill = GridBagConstraints.HORIZONTAL;
      c.weightx = 1.0;
      c.weighty = 1.0;
      c.anchor = GridBagConstraints.PAGE_START;
      c.gridx = 2;
      c.gridy = 0;
      gridBagPanel.add(button, c);

      button = new JButton("Long-Named Button 4");
      c.fill = GridBagConstraints.HORIZONTAL;
      c.ipady = 40;
      c.weightx = 1.0;
      c.weighty = 1.0;
      c.anchor = GridBagConstraints.PAGE_START;
      c.gridwidth = 3;
      c.gridx = 0;
      c.gridy = 1;
      gridBagPanel.add(button, c);

      // and then add the gridbag panel to the contentPane at the top
      pane.add(gridBagPanel, BorderLayout.PAGE_START);
  }

  private static void createAndShowGUI() {

      JFrame frame = new JFrame("GridBagLayoutDemo");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      addComponentsToPane(frame.getContentPane());

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

  public static void main(String[] args) {

      javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
      });
  }
}

---

Ok, it works, I guess I can remove this code and it will work anyway.

Code:

---

c.weighty = 1.0;
c.anchor = GridBagConstraints.PAGE_START;

---

Is there a way to do this using just GridBagLayout?

EDIT: wait, we are creating a new panel just to put it inside the top of another panel?

I'm trying to add a labeled JTextField to a cell of the GridBagLayout.
So I put the JLabel and the JTextField inside a Box and then I put that
Box inside a cell, but there is a misalignment on the left.

How can I solve this? I tried setHorizontalAlignment(), but it does nothing.

http://img4.imageshack.us/img4/1435/immagineeks.png

Code:

---

package sandbox;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridBagConstraints;

import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

public class GridBagLayoutDemo2 {
       
        public static void addComponentsToPane(Container pane) {
                JPanel gridBagPanel = new JPanel();
                Box myBox = Box.createVerticalBox();
               
                JLabel myLabel = new JLabel("Some text");
//                myLabel.setHorizontalAlignment(SwingConstants.LEFT); // useless
                myBox.add(myLabel);
               
                JTextField configUrlField = new JTextField("Some long text", 15);
//                configUrlField.setHorizontalAlignment(SwingConstants.LEFT); // useless
                myBox.add(configUrlField);
               
                GridBagConstraints myGBC = new GridBagConstraints();
                myGBC.weightx = 1.0;
                myGBC.weighty = 1.0;
                myGBC.anchor = GridBagConstraints.PAGE_START;
                myGBC.fill = GridBagConstraints.HORIZONTAL;
                myGBC.gridx = 0;
                myGBC.gridy = 0;

                gridBagPanel.add(myBox, myGBC);
                pane.add(gridBagPanel, BorderLayout.PAGE_START);
        }
       
        private static void createAndShowGUI() {
               
              JFrame frame = new JFrame("GridBagLayoutDemo");
              frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       
              addComponentsToPane(frame.getContentPane());
       
              frame.pack();
              frame.setVisible(true);
          }
       
          public static void main(String[] args) {
       
              javax.swing.SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    createAndShowGUI();
                }
              });
          }
}

---