display icon/text on right of selected node in jtree

[pavan in]

I want to display an icon or a text to the right of the selected node on the JTree. Any idea on how to implement this?
Say,
100 A
where, 100 is selected and A is beside it and not selected.
Thanks

[Nathan Pruett]

You can easily extend DefaultTreeCellRenderer to do this and set it as the cell renderer for your JTree by calling tree.setCellRenderer() with your new cell renderer.

[pavan in]

Nathan, I have extended defaultTreeCellRenderer. But, how to set the text so that some part of text is selected and some not selected.
say,
100 A
where 100 is selected and A is not selected.
See code below -
public Component getTreeCellRendererComponent(
JTree m_tree, Object m_value, boolean m_isSelected,
boolean m_isExpanded, boolean m_isLeaf, int m_row,
boolean m_hasFocus) {

super.getTreeCellRendererComponent( m_tree, m_value, m_isSelected,
m_isExpanded, m_isLeaf, m_row, m_hasFocus);
Component compObject = this;

if ( m_value instanceof EuamDefaultMutableTreeNode ) {
EuamDefaultMutableTreeNode node = (EuamDefaultMutableTreeNode)m_value;
setText( node.getText() );
setIcon(m_isExpanded ? node.getOpenIcon() : node.getClosedIcon() );

}
else {
setText(m_value.toString());
}
return compObject;
}

[Nathan Pruett]

Pavan,

Here's an example of how I added the desired functionality to the renderer... Enjoy!

import javax.swing.*;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import java.awt.*;
 
public class PavanRenderer extends DefaultTreeCellRenderer {
    public Component getTreeCellRendererComponent(
            JTree m_tree, Object m_value, boolean m_isSelected,
            boolean m_isExpanded, boolean m_isLeaf, int m_row,
            boolean m_hasFocus) {
        Component compObject = super.getTreeCellRendererComponent(
                m_tree, m_value, m_isSelected,
                m_isExpanded, m_isLeaf, m_row, m_hasFocus);;
 
        if ( m_value instanceof EuamDefaultMutableTreeNode ) {
            EuamDefaultMutableTreeNode node = (EuamDefaultMutableTreeNode)m_value;
            setText( Integer.toString( node.getNumber() ) );
            setIcon(m_isExpanded ? node.getOpenIcon() : node.getClosedIcon() );
            JPanel p = new JPanel();
            p.setBackground( UIManager.getColor( "Tree.textBackground" ) );
            p.setForeground( UIManager.getColor( "Tree.textForeground" ) );
            p.setLayout( new BorderLayout() );
            p.add( compObject, BorderLayout.WEST );
            JLabel l = new JLabel( node.getText() );
            l.setFont( UIManager.getFont( "Tree.font" ) );
            p.add( l, BorderLayout.EAST );
            compObject = p;
        }
        else {
            setText(m_value.toString());
        }
        return compObject;
    }
 
    public static void main( String[] args ) {
        JFrame f = new JFrame( "Pavan Renderer Test" );
        JTree tree = new JTree( new EuamTreeModel() );
        tree.setCellRenderer( new PavanRenderer() );
        f.getContentPane().add( new JScrollPane( tree ) );
        f.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
        f.setSize( 400, 600 );
        f.show();
    }
}
 
class EuamTreeModel extends DefaultTreeModel {
 
    public EuamTreeModel() {
        super( new EuamDefaultMutableTreeNode(), true );
        initTree();
    }
 
    private void initTree() {
        EuamDefaultMutableTreeNode root = (EuamDefaultMutableTreeNode)getRoot();
        root.setText( "Root" );
        root.setNumber( 0 );
        for ( int i = 1; i <= 10; i++ ) {
            EuamDefaultMutableTreeNode node = new EuamDefaultMutableTreeNode( "Child_" + i, i );
            root.add( node );
        }
    }
}
 
class EuamDefaultMutableTreeNode extends DefaultMutableTreeNode {
 
    private String text;
    private int number;
    private Icon openIcon;
    private Icon closedIcon;
 
    public EuamDefaultMutableTreeNode() {
        this( "Default", 0 );
    }
 
    public EuamDefaultMutableTreeNode( String text, int number ) {
        this.text = text;
        this.number = number;
        this.openIcon = new RedCircle();
        this.closedIcon = new BlueCircle();
    }
 
    public String getText() {
        return text;
    }
 
    public void setText( String text ) {
        this.text = text;
    }
 
    public Icon getOpenIcon() {
        return openIcon;
    }
 
    public void setOpenIcon( Icon icon ) {
        this.openIcon = icon;
    }
 
    public Icon getClosedIcon() {
        return closedIcon;
    }
 
    public void setClosedIcon( Icon icon ) {
        this.closedIcon = icon;
    }
 
    public int getNumber() {
        return number;
    }
 
    public void setNumber( int number ) {
        this.number = number;
    }
 
    private class RedCircle implements Icon {
 
        public int getIconWidth() {
            return 16;
        }
 
        public int getIconHeight() {
            return 16;
        }
 
        public void paintIcon( Component comp, Graphics g, int x, int y ) {
            g.setColor( comp.getBackground() );
            g.fillRect( x, y, getIconWidth(), getIconHeight() );
            g.setColor( Color.red );
            g.fillOval( x, y, getIconWidth(), getIconHeight() );
        }
    }
 
    private class BlueCircle implements Icon {
 
        public int getIconWidth() {
            return 16;
        }
 
        public int getIconHeight() {
            return 16;
        }
 
        public void paintIcon( Component comp, Graphics g, int x, int y ) {
            g.setColor( comp.getBackground() );
            g.fillRect( x, y, getIconWidth(), getIconHeight() );
            g.setColor( Color.blue );
            g.fillOval( x, y, getIconWidth(), getIconHeight() );
        }
    }
}

[pavan in]

Thanks a loot Nathan. I havent run it, but I think it will work. That was very very useful.
Thanks again.

[pavan in]

Nathan,
Can I perform this task on node selection (in valuechanged method of TreeSelectionAdapter)?
I have a tree that is built initially, and I get the text (to be displayed next to node text) from the database only when the user selects the node.
Can I do this task?
Is node.setUserObject() do the task?
Thanks.

[Nathan Pruett]

In the example I provided, the EuamDefaultMutableTreeNode class contains the number... so you would initially start it out at 0 (or some other default value) when you created it, and then in your selection listener you would cast the selected node to a EuamDefaultMutableTreeNode and call setNumber( int ) on it...

[pavan in]

Nathan,
Is it possible to associate an listener (say, mouseClick) on the text displayed on the right hand side of the node data.
i.e, for the text '100 A', can I associate an listener to the text 'A' so that when the user clicks on 'A', some method is called.
Thanks

[Nathan Pruett]

Yes... you could just add a MouseListener to the tree or the cell renderer.

[pavan in]

I dont want the listener to be added to the text on the left hand side. MouseListener will corresponds to the whole text (left and right), isnt it?
How do I add listener to the cell renderer?

[Nathan Pruett]

Sorry... just tried this out for real, and the tree "eats" all the events for the rendererers, so you can't add a listener on the renderer.

However, I did find some code here that shows how to differentiate areas of the renderer using a listener on the JTree.