JSplitPane events

[seema prakash]

Hi,
I'm using a JSplitPane component with two JPanels inside each side of the SplitPane.
I'm using OneTouchExpandable property of JSplitPane and setting it to true initially.
When the split pane is first shown, both the panels are visible.
Well, I want to add code when the divider is collapsed.
What is the action performed for this just like action performed for jbutton?
Please help.
Thanks.

[Michael Dunn]

set your own UI, overriding the createRight/LeftOneTuchButtons to add an
actionListener to the button

[Craig Wood]

You can use a PropertyChangeListener and the DIVIDER_LOCATION_PROPERTY which you
can find listed in the Field Summary section of the JSplitPane api. For additional
information see Using PropertyChangeListener.

import java.awt.*;
import java.beans.*;
import javax.swing.*;
 
public class SplitPaneActionTest implements PropertyChangeListener {
    public void propertyChange(PropertyChangeEvent e) {
        //System.out.printf("The %s property changed from %s to %s%n",
        //           e.getPropertyName(), e.getOldValue(), e.getNewValue());
        JSplitPane splitPane = (JSplitPane)e.getSource();
        int loc = ((Integer)e.getNewValue()).intValue();
        int size = splitPane.getDividerSize();
        int width = splitPane.getWidth();
        if(loc == 1 || loc+size+1 == width)
            System.out.printf("Divider collapsed %s%n",
                               (loc == 1) ? "left" : "right");
    }
 
    private JSplitPane getContent() {
        JSplitPane splitPane = new JSplitPane();
        String prop = JSplitPane.DIVIDER_LOCATION_PROPERTY;
        splitPane.addPropertyChangeListener(prop, this);
        splitPane.setLeftComponent(getPanel(Color.yellow));
        splitPane.setRightComponent(getPanel(Color.magenta));
        splitPane.setDividerLocation(200);
        splitPane.setOneTouchExpandable(true);
        return splitPane;
    }
 
    private JPanel getPanel(Color color) {
        JPanel panel = new JPanel();
        panel.setBackground(color);
        panel.setPreferredSize(new Dimension(200,200));
        return panel;
    }
 
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setContentPane(new SplitPaneActionTest().getContent());
        f.setSize(400,200);
        f.setVisible(true);
    }
}

If you are not using oneTouchExpandable you would include the width of the minimumSize of
each component in the test to detect collapse.

            int leftMinWidth = ((JComponent)splitPane.getLeftComponent())
                                    .getMinimumSize().width;
            if(loc-leftMinWidth == 1 || loc+size+rightMinWidth+1 == width)

[seema prakash]

Thanks for the help. I'm posting a snippet of my code so that it may be useful for someone who might have the same problem. I added a componentListener. Here is the code:

(((BasicSplitPaneUI)pairWorkAreaSpltPane.getUI()).getDivider()).addComponentListener(new ComponentAdapter() {
                public void componentMoved(ComponentEvent ce) { 
                Component comp = pairWorkAreaSpltPane.getBottomComponent();
                if( comp.getHeight() == 0){
                // show top component help file
                } else {
                //show bottom component help file
                }
                }
});