Support for Highlighting in a custom View

Question

Hello there!
I am extending somebody else's framework code to create an XML editor. It uses an extended DefaultStyledDocument and a JEditorPane for this purpose. I need to implement copy/paste functionality in the framework. I have a problem with the Highlighter:
I have a view called HiddenTagView(different from the javax.swing.text.html package's HiddenTagView) that displays the starting and enclosing element tags in a JPanel with a border(the border is different for starting and enclosing tags.) The code is given below.
For some reason, the default Highlighter doesn't affect the appearance of this view when it is selected.
The code for the paint method of EditableView(super class of HiddenTagView, again it is NOT the one from javax.swing.text.html package) is also given below.
I changed the paint method of EditableView to support layered highlighting. But after doing this, The JEditorPane displays nothing! It goes completely blank! My code to support highlighing is in the paint method of EditableView:
if (isVisible)
{   //my attempt to support layered highlighting,
//my code starts here
Component co = getContainer();
if (co instanceof JTextComponent)
     int p0 = getStartOffset();
     int p1 = getEndOffset();
     JTextComponent tc = (JTextComponent) c;
     Highlighter h = tc.getHighlighter();
     if (h instanceof LayeredHighlighter) {
     ((LayeredHighlighter)h).paintLayeredHighlights
          (g, p0, p1, allocation, tc, this);
} //my code for layedred highlighting ends here
This code is also included below as a part of the whole paint() method of EditableView.
Can anyone please please help me in making highlighting work in the HiddenTagView? Any tip or help will be highly appreciated.
Thanks a lot!
Regards,
Java Student
//HiddenTagView
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.text.AttributeSet;
import javax.swing.text.Document;
import javax.swing.text.Element;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.Serializable;
public class HiddenTagView extends EditableView
private Element elem;
     public HiddenTagView(Element e)
super(e);
elem = e;
yAlign = 0.5f;
protected Component createComponent()
final JPanel surroundPanel = new JPanel(new FlowLayout())
public boolean isVisible()
return XMLEd.getDelimitersVisible();
surroundPanel.setBackground(null);
String leafName = getElement().getName();
String elemName = leafName.substring(0, leafName.indexOf("-"));
JLabel tf = new JLabel(elemName);
Document doc = getDocument();
          XMLDocument doc1 = (XMLDocument)getDocument();
// Create a panel to wrap the textfield so that the textfields
// laf border shows through.
JPanel panel = new JPanel(new BorderLayout());
panel.setName(elemName);
panel.setBackground(null);
panel.add(tf);
if (isEndTag())
panel.setBorder(EndBorder);
surroundPanel.add(panel);
} else
panel.setBorder(StartBorder);
surroundPanel.add(panel);
surroundPanel.addMouseListener(new MouseAdapter()
public void mouseEntered(MouseEvent e)
Cursor defaultCursor = new Cursor(Cursor.DEFAULT_CURSOR);
surroundPanel.setCursor(defaultCursor);
return surroundPanel;
public float getAlignment(int axis)
if (axis == View.Y_AXIS)
return 0.5f;
return 0.0f;
public float getMinimumSpan(int axis)
     int len = elem.getName().length();
if (axis == View.X_AXIS)
return 50;
return 30;
public float getPreferredSpan(int axis)
          int len = elem.getName().length();
if (axis == View.X_AXIS)
return (len+1)*5; //changed from (len+1)*10 by Swati
return 20;
public float getMaximumSpan(int axis)
          int len = elem.getName().length();
if (axis == View.X_AXIS)
               return 50;
return 30;
public String toString()
          return ("HiddenTagView [" + this.getStartOffset() + ", "
+ this.getEndOffset() + "]");
boolean isEndTag()
AttributeSet as = getElement().getAttributes();
if (as != null)
Object end = as.getAttribute(XML.Attribute.ENDTAG);
if (end != null && (end instanceof Boolean) &&
((Boolean) end).equals(new Boolean("true")))
return true;
return false;
float yAlign;
boolean isSettingAttributes;
static final int circleR = 3;
static final int circleD = circleR * 2;
static final int tagSize = 6;
static final int padding = 3;
static final Color UnknownTagBorderColor = Color.black;
static final Border StartBorder = new StartTagBorder();
static final Border EndBorder = new EndTagBorder();
static class StartTagBorder implements Border, Serializable
public void paintBorder(Component c, Graphics g, int x, int y,
int width, int height)
          //draws the border
public boolean isBorderOpaque()
return false;
} // End of class HiddenTagView.StartTagBorder
static class EndTagBorder implements Border, Serializable
public void paintBorder(Component c, Graphics g, int x, int y,
int width, int height)
//draws border for end tags
public Insets getBorderInsets(Component c)
return new Insets(2, tagSize + 2 + padding, 2, 2 + padding);
public boolean isBorderOpaque()
return false;
} // End of class HiddenTagView.EndTagBorder
//paint method of EditableView
public void paint(Graphics g, Shape allocation)
Component c = getComponent();
Container host = getContainer();
if (host != null &&
isVisible != ((JTextComponent) host).isEditable())
isVisible = ((JTextComponent) host).isEditable();
preferenceChanged(null, true, true);
host.repaint();
* Note: we cannot tweak the visible state of the
* component in createComponent() even though it
* gets called after the setParent() call where
* the value of the boolean is set. This
* because, the setComponentParent() in the
* superclass, always does a setVisible(false)
* after calling createComponent(). We therefore
* use this flag in the paint() method to
* setVisible() to true if required.
if (isVisible)
{   //my attempt to support layered highlighting, code starts
here
          Component co = getContainer();
          if (co instanceof JTextComponent)
               int p0 = getStartOffset();
               int p1 = getEndOffset();
               JTextComponent tc = (JTextComponent) c;
               Highlighter h = tc.getHighlighter();
               if (h instanceof LayeredHighlighter) {
((LayeredHighlighter)h).paintLayeredHighlights
                         (g, p0, p1, allocation, tc,
this);
          } //my code for layedred highlighting ends here
super.paint(g, allocation);
Document d = getDocument();
g.drawString("Hello", (int) c.getBounds().getX() + 10, (int)
c.getBounds().getY());
} else
setSize(0, 0);
}

Answer 1

Hi there!
oops..I had made a small mistake in the highlighting code in the paint() method of EditableView.
if (isVisible)
{   //my attempt to support layered highlighting,
// my code starts here
Component co = getContainer();
if (co instanceof JTextComponent)
     int p0 = getStartOffset();
     int p1 = getEndOffset();
     JTextComponent tc = (JTextComponent) co; //I had c here in my previous version instead of co
     Highlighter h = tc.getHighlighter();
     if (h instanceof LayeredHighlighter) {
     ((LayeredHighlighter)h).paintLayeredHighlights
                    (g, p0, p1, allocation, tc, this);
} //my code for layered highlighting ends here
Now, the JEditorPane doen't get blank on execution. But I still cannot see the HiddenTagView highlighted when I select it.
Can anyone please please help me?
thanks,
Java Student