Jtree renderers

From:
"Rexx Magnus" <trashcan@uk2.net>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 17 Feb 2008 10:46:26 -0000
Message-ID:
<op.t6nz7oztp9vcmo@deanes-mac.local>
I'm having problems writing a custom JTree renderer.

I have created code for a tree that displays checkboxes for true/false =

data (represented by checkboxnode types) and one for text and numerical =
 =

data which will use a spinner. Problems occur in getCellEditorValue() wh=
en =

I try to filter out the type of renderer to deal with the input. This is=
  =

due to the getLeafRenderer() method.

It only returns leafRenderer, and I can't work out a way of getting it t=
o =

return the different types of renderer instead of just one. It needs to =
 =

return leafRenderer when it is a checkbox (which works fine if you chang=
e =

the method's return type to JCheckBox as it was in the example) and =

leafSpinRenderer when it is a spinner. There are other ways of finding o=
ut =

the values, but they reflect the old value (this is in the event handler=
  =

and looks messy and incorrect).
Most of the examples of checkbox node trees don't have any explanation o=
f =

how the code works, so I'm flying blind.

class CharacterNodeRenderer implements TreeCellRenderer {

     private JCheckBox leafRenderer = new JCheckBox();
     private JSpinner leafSpinRenderer = new JSpinner();
     private DefaultTreeCellRenderer nonLeafRenderer = new =

DefaultTreeCellRenderer();
     Color selectionBorderColor, selectionForeground, selectionBackgroun=
d,
             textForeground, textBackground;

// ********* this was originally written as protected JCheckBox =

getLeafRenderer() in example code.\

     protected Object getLeafRenderer() {

         return leafRenderer;
     }

     public CharacterNodeRenderer() {
         Font fontValue;
         fontValue = UIManager.getFont("Tree.font");
         if (fontValue != null) {
             leafRenderer.setFont(fontValue);
         }
         Boolean booleanValue = (Boolean) =

UIManager.get("Tree.drawsFocusBorderAroundIcon");
         leafRenderer.setFocusPainted((booleanValue != null) && =

(booleanValue.booleanValue()));

         selectionBorderColor = =

UIManager.getColor("Tree.selectionBorderColor");
         selectionForeground = =

UIManager.getColor("Tree.selectionForeground");
         selectionBackground = =

UIManager.getColor("Tree.selectionBackground");
         textForeground = UIManager.getColor("Tree.textForeground");
         textBackground = UIManager.getColor("Tree.textBackground");
     }

     public Component getTreeCellRendererComponent(JTree tree, Object va=
lue,
             boolean selected, boolean expanded, boolean leaf, int row,
             boolean hasFocus) {

         Component returnValue;
         if (leaf & (((DefaultMutableTreeNode) value).getUserObject() =

instanceof CheckBoxNode)) {

             String stringValue = tree.convertValueToText(value, selec=
ted,
                     expanded, leaf, row, false);
             leafRenderer.setText(stringValue);
             leafRenderer.setSelected(false);

             leafRenderer.setEnabled(tree.isEnabled());

             if (selected) {
                 leafRenderer.setForeground(selectionForeground);
                 leafRenderer.setBackground(selectionBackground);
             } else {
                 leafRenderer.setForeground(textForeground);
                 leafRenderer.setBackground(textBackground);
             }

             //for checkboxes, read the state from the data and set box
             if ((value != null) && (value instanceof =

DefaultMutableTreeNode)) {
                 Object userObject = ((DefaultMutableTreeNode) =

value).getUserObject();
                 if (userObject instanceof CheckBoxNode) {
                     CheckBoxNode node = (CheckBoxNode) userObject;
                     leafRenderer.setText(node.getText());
                     leafRenderer.setSelected(node.isSelected());
                 }
             }
             returnValue = leafRenderer;
             //read data for stats and set values
         } else if (leaf & (((DefaultMutableTreeNode) =

value).getUserObject() instanceof Stat)) {
             Object userObject = ((DefaultMutableTreeNode) =

value).getUserObject();
             Stat node = (Stat) userObject;
             leafSpinRenderer.setValue(node.get());
             returnValue = leafSpinRenderer;
         } else {
             returnValue = =

nonLeafRenderer.getTreeCellRendererComponent(tree,
                     value, selected, expanded, leaf, row, hasFocus);
         }
         return returnValue;
     }
}

class CharacterNodeEditor extends AbstractCellEditor implements =

TreeCellEditor {

     CharacterNodeRenderer renderer = new CharacterNodeRenderer();
     ChangeEvent changeEvent = null;
     JTree tree;

     public CharacterNodeEditor(JTree tree) {
         this.tree = tree;
     }

     public Object getCellEditorValue() {
         if (renderer.getLeafRenderer() instanceof JCheckBox){

// ************* this secton works fine if its returning a JCheckBox, bu=
t =

I don't always want it to.

         JCheckBox checkbox = renderer.getLeafRenderer();
         CheckBoxNode checkBoxNode = new CheckBoxNode(checkbox.getText=
(),
                 checkbox.isSelected());
         return checkBoxNode;
         }
         else if (renderer.getLeafRenderer() instanceof JSpinner)
         {
// ************* I was going to add different return types for different=
  =

node renderers, as you can see

            // JSpinner statbox = renderer.getLeafRenderer();
            // Stat statnode = new Stat(statbox.getValue());
         }
     }

     @Override
     public boolean isCellEditable(EventObject event) {
         boolean returnValue = false;
         if (event instanceof MouseEvent) {
             MouseEvent mouseEvent = (MouseEvent) event;
             TreePath path = tree.getPathForLocation(mouseEvent.getX()=
,
                     mouseEvent.getY());

             System.out.println(path);

             if (path != null) {
                 Object node = path.getLastPathComponent();
                 if ((node != null) && (node instanceof =

DefaultMutableTreeNode)) {
                     DefaultMutableTreeNode treeNode = =

(DefaultMutableTreeNode) node;
                     Object userObject = treeNode.getUserObject();
                     returnValue = ((treeNode.isLeaf()) && ((userObjec=
t =

instanceof CheckBoxNode) || (userObject instanceof Stat)));

                 }
             }
         }
         return returnValue;
     }

  /*
  public boolean isCellEditable(EventObject event) {
     boolean returnValue = super.isCellEditable(event);
     if (returnValue) {
       Object node = tree.getLastSelectedPathComponent();
       if ((node != null) && (node instanceof TreeNode)) {
         TreeNode treeNode = (TreeNode) node;
         returnValue = treeNode.isLeaf();
       }
     }
     return returnValue;
   }
*/

     public Component getTreeCellEditorComponent(JTree tree, Object valu=
e,
             boolean selected, boolean expanded, boolean leaf, int row) =
{

         Component editor = renderer.getTreeCellRendererComponent(tree=
, =

value,
                 true, expanded, leaf, row, true);

         // editor always selected / focused
         ItemListener itemListener = new ItemListener() {

             public void itemStateChanged(ItemEvent itemEvent) {
                 if (stopCellEditing()) {
                     fireEditingStopped();
                 }
             }
         };
         if (editor instanceof JCheckBox) {
             ((JCheckBox) editor).addItemListener(itemListener);
         }
         else if (editor instanceof JSpinner)
         {
             ((JSpinner) editor).addItemListener(itemListener);
         }
         return editor;
     }
}

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