Tree Editors and Renderers

Question

What I am currently trying to implement is a tree editor renderer that displays label and a text field next to a tree node.
The label contains text describing the contents of the text field to the right.
The requirement is that the user can click in the textfield area and type a new value, which when they press return is accepted.
My problem is that in order to detect single clicks in the textfield area to enable the editor for that tree node, I am implementing an Immediate Editor along the lines in the Geary Swing Book.
However, a method to calculate the correct offset is not working:
PMSPropertyBrowserTreeCellRenderer.getPropertyValueTextFieldOffset fails to calculate the correct value as two things appear to fail
1. the "lastRow" member of the Tree is not the last component selected
2. the call to obtain the Graphics class from the renderer's panel always returns null
From Immediate Editor
* Provides the means to edit a cell immediately with a mouse click
* @param event
* @return true if the event is of the right type
protected boolean canEditImmediately(EventObject event)
boolean retval = false;
if (event instanceof MouseEvent)
MouseEvent me = (MouseEvent)event;
retval = inTextFieldHitRegion(me);
return retval;
* Should determine if the pointer is in the region of the property text field
* @param me
* @return id the mouse pointer is in the text field
private boolean inTextFieldHitRegion(MouseEvent me)
// obtain the place in the tree where this mouse event came from
TreePath path = tree.getPathForLocation(me.getX(), me.getY());
PMSPropertyBrowserTreeNode node =
(PMSPropertyBrowserTreeNode)path.getLastPathComponent();
boolean retval = false;
// if the node is a leaf
if (node.isLeaf())
// determine if mouse point is in the JTextField part of the renderer component
Rectangle bounds = tree.getRowBounds(this.lastRow);
Dimension textFieldOffset = renderer.getPropertyValueTextFieldOffset();
bounds.translate(
offset + textFieldOffset.width,
textFieldOffset.height);
retval = bounds.contains(me.getPoint());
return retval;
public boolean shouldSelectCell(EventObject event)
GUILog.log.writeLog(
GUILog.logTypes.ADMINISTRATIVE_EVENT,
"shouldSelectCell called");
boolean retval = false;
if (event instanceof MouseEvent)
MouseEvent me = (MouseEvent)event;
TreePath path = tree.getPathForLocation(me.getX(), me.getY());
PMSPropertyBrowserTreeNode node =
(PMSPropertyBrowserTreeNode)path.getLastPathComponent();
boolean inField = !inTextFieldHitRegion(me);
retval = node.isLeaf() || !inTextFieldHitRegion(me);
return retval;
... end from ImmediateEditor
import java.awt.*;
import javax.swing.*;
import javax.swing.JTree;
import javax.swing.tree.*;
import java.awt.Component;
public class PMSPropertyBrowserTreeCellRenderer extends DefaultTreeCellRenderer
private JPanel propertyPanel = new JPanel();
private JLabel propertyValueLabel = new JLabel();
protected JTextField propertyValueTextField = new JTextField();
private Component spacer = Box.createHorizontalStrut(5);
public PMSPropertyBrowserTreeCellRenderer()
super();
propertyPanel.setBackground(UIManager.getColor("Tree.textBackground"));
setOpaque(false);
propertyValueTextField.setOpaque(false);
propertyValueTextField.setBorder( BorderFactory.createLoweredBevelBorder());
propertyValueTextField.setText("<empty>");
propertyPanel.setOpaque(false);
propertyPanel.setLayout(new FlowLayout(FlowLayout.CENTER,0,0));
propertyPanel.add(this);
propertyPanel.add(spacer);
propertyPanel.add(propertyValueTextField);
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus)
* Gives the offset for the tree node as far as the text component
* Currently the graphics reference returns null.
* @return an offset into the text field component
public Dimension getPropertyValueTextFieldOffset()
Graphics g = propertyPanel.getGraphics();
int offset = 0;
if (g != null)
try
FontMetrics fm = g.getFontMetrics();
offset =
fm.stringWidth(getText()+spacer.getPreferredSize().width);
catch (Exception ex)
// nothing happens if we get an exception
finally
g.dispose();
} // end if
return new Dimension(offset,0);
} // end method

Answer 1

JTree has a setRowHeight(int rowHeight) method. "If
the specified value is less than or equal to zero the current cell
renderer is queried for each row's height."
(Say if you're reposting this in the Swing forum.)