Trees - The Definitive Guide to Java Swing - page 635

DefaultCellEditor Class
The DefaultCellEditor class serves as an editor for both tree nodes and table cells. The class
allows you to easily provide a text editor, combo box editor, or check box editor to modify the
contents of a node or cell.
The DefaultTreeCellEditor class, described next, uses this class to provide an editor for a
customized text field, maintaining the appropriate node-type icon based on a TreeCellRenderer .
Creating a DefaultCellEditor
When you create a DefaultCellEditor instance, you provide the JTextField , JComboBox , or
JCheckBox to use as the editor.
public DefaultCellEditor(JTextField editor)
JTextField textField = new JTextField();
TreeCellEditor editor = new DefaultCellEditor(textField);
public DefaultCellEditor(JComboBox editor)
public static void main (String args[]) {
JComboBox comboBox = new JComboBox(args);
TreeCellEditor editor = new DefaultCellEditor(comboBox);
...
}
public DefaultCellEditor(JCheckBox editor)
JCheckBox checkBox = new JCheckBox();
TreeCellEditor editor = new DefaultCellEditor(checkBox);
With a JTree , you should use the DefaultTreeCellEditor if you want a JTextField editor.
That text field will share the same font and use the appropriate editor border for the tree. When
a JCheckBox is used as the editor, the node for the tree should be either a Boolean value or a
String that can be converted to a Boolean . (If you are unfamiliar with conversion from String
to Boolean , see the Javadoc for the Boolean constructor that accepts a String .)
After creating an editor, you tell the tree to use it with a call similar to tree.
setCellEditor(editor) . And don't forget to make the tree editable with tree.
setEditable(true) . For instance, if you wanted an editable combo box as your editor,
the following source code would work:
JTree tree = new JTree(...);
tree.setEditable(true);
String elements[] = { "Root", "chartreuse", "rugby", "sushi"} ;
JComboBox comboBox = new JComboBox(elements);
comboBox.setEditable(true);
TreeCellEditor editor = new DefaultCellEditor(comboBox);
tree.setCellEditor(editor);
This code produces the screen shown in Figure 17-13 when editing the basketball node.
Notice that there is no icon to indicate the type of node being edited. This is rectified with the