JXTaskPaneContainer grows wrongly when resizing window

Question

I have a JXTaskPaneContainer on the right hand side of my JFrame which contains hyperlinks and labels. The window's main parts should be:

• a large area on the left for the text
• a smaller area on the right with the messages and the actions

Now, the problem is that adding a lot of new elements causes the container to grow to the left and over the text:

It gets even weirder when having the JXTaskPaneContainer inside a javax.swing.JScrollPane (video/yt).

The problem seems to lie with the JXLabel. I suspect it's the word wrap? Any ideas how to fix this?

[Example] Self-contained example as per request. Full source on github.

package layoutproblemSSCEC;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeListener;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

import org.jdesktop.swingx.JXButton;
import org.jdesktop.swingx.JXLabel;
import org.jdesktop.swingx.JXTaskPane;
import org.jdesktop.swingx.JXTaskPaneContainer;

public class SwingWindow {

    private JFrame frame;
    String dolorem = "Sed ut perspiciatis unde omnis iste natus error sit "
            + "voluptatem accusantium doloremque laudantium, totam rem aperiam, "
            + "eaque ipsa quae ab illo inventore veritatis et quasi architecto "
            + "beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem "
            + "quia voluptas sit aspernatur aut odit aut fugit, sed quia "
            + "consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. "
            + "Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, "
            + "consectetur, adipisci velit, sed quia non numquam eius modi tempora "
            + "incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut "
            + "enim ad minima veniam, quis nostrum exercitationem ullam corporis "
            + "suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? "
            + "Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse "
            + "quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat "
            + "quo voluptas nulla pariatur?";

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    SwingWindow window = new SwingWindow();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public SwingWindow() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        final JXTaskPaneContainer panels = new JXTaskPaneContainer();
        JScrollPane scrollpanel = new JScrollPane(panels);

        Container content = frame.getContentPane();
        content.add(new JTextArea(dolorem), BorderLayout.CENTER);
        content.add(scrollpanel, BorderLayout.EAST);
        content.add(new JXButton(new AbstractAction("Click me") {

            public void actionPerformed(ActionEvent arg0) {
                JXTaskPane panel = new JXTaskPane("test");
                JXLabel lbl = new JXLabel(dolorem);
                lbl.setLineWrap(true);
                panel.add(lbl);
                panels.add(panel);
            }
        }), BorderLayout.NORTH);

        panels.add(new JXTaskPane("Click the button, then resize"));
    }

}

Answer 1

I wish there was a concise answer to my question. I fear there is not. I resolved the issue by creating a new layout, based on a GridBagLayout instead of BorderLayout.

There was also the issue of setting a minimum preferred size. Without calling setMinimumSize(new Dimension(200, 127)), the container's width seemed to shrink indefinitely, despite advertising a preferred width of 600. I'm still not sure where this comes from. The numbers are from the component's initial preferred size.

The tutorial on oracle's site helped me here. The important part is finding weights which work. A weight value greater than 0 allows the component to grow and shrink.

This is what the layout code looks like now:

frmvanInput = new JFrame(); // window
// ... captions, titles, etc

frmvanInput.setContentPane(new JPanel(new GridBagLayout()));

// ... more initializing

/** 
 * LAYOUTS
 */
final Container contentPane = frmvanInput.getContentPane();

// the menu bar is on top, stretches all the way right
GridBagConstraints menuBarLayout = new GridBagConstraints();
// top left
menuBarLayout.anchor = GridBagConstraints.FIRST_LINE_START; // push to the top left
menuBarLayout.gridx = 0; 
menuBarLayout.gridy = 0;
// manage width
menuBarLayout.gridwidth = 2; // stretch
menuBarLayout.fill = GridBagConstraints.HORIZONTAL; // fill all x-space
menuBarLayout.weightx = 0.5; // a weight > 0 allows for resizing
//add
contentPane.add(menuBar, menuBarLayout);

// the text field is under the menu on the left and shares a row with the errors panel/scroll pane
GridBagConstraints textfieldLayout = new GridBagConstraints();
// top left
textfieldLayout.anchor = GridBagConstraints.FIRST_LINE_START; // push to the top left
textfieldLayout.gridx = 0; // col left
textfieldLayout.gridy = 1; // row center
// manage stretching
textfieldLayout.weightx = 0.5; // resizable
textfieldLayout.weighty = 0.5; // resizable
textfieldLayout.fill = GridBagConstraints.BOTH;
// add
contentPane.add(txtEditor, textfieldLayout);

errorScrollPane = new JScrollPane(containerTaskPanel);
// prevent indefinate shrinking
errorScrollPane.setMinimumSize(new Dimension(200, 127));

GridBagConstraints scrollpanelLayout = new GridBagConstraints();
// middle, right
scrollpanelLayout.anchor = GridBagConstraints.FIRST_LINE_END;
scrollpanelLayout.gridx = 1; // right row
scrollpanelLayout.gridy = 1; // center column
// stretch to fill
scrollpanelLayout.weightx = 0.5; // resizable
scrollpanelLayout.weighty = 0.5; // resizable
scrollpanelLayout.fill = GridBagConstraints.BOTH;
// add our controls to the visible world
contentPane.add(errorScrollPane, scrollpanelLayout);

// the emitter panel has the bottom row to itself
GridBagConstraints emitterpanelLayout = new GridBagConstraints();
// bottom left
emitterpanelLayout.anchor = GridBagConstraints.LAST_LINE_START;
emitterpanelLayout.gridx = 0; // col left
emitterpanelLayout.gridy = 2; // row bottom
// stretch width
emitterpanelLayout.weightx = 0.5;
emitterpanelLayout.gridwidth = 2;
// manage height:
emitterpanelLayout.weighty = 0.1;
emitterpanelLayout.fill = GridBagConstraints.BOTH;
// add
contentPane.add(emitterScrollPane, emitterpanelLayout);