Cannot remove attributes in HTMLDocument

Question

With a JTextPane, HTMLDocument and two JButtons I can select a piece of text and format it (bold for example). Then I want to select it again and clear the format (non bold for example).
I do this with the code below.
The editor shows the text correctly. But when exporting the document to HTML (with HTMLEditorKit.write...), the text which I cleared of formattings is gone!
I only want to clear the formatting, not the text.
Any idea?
int start = editor.getSelectionStart();
int end = editor.getSelectionEnd();
Element element = htmlDocument.getCharacterElement(start);
AttributeSet attributeSet = element.getAttributes();
StyleSheet styleSheet = htmlDocument.getStyleSheet();
styleSheet.removeAttributes(attributeSet, element.getAttributes());
htmlDocument.setCharacterAttributes(start, end - start, attributeSet, true);

Answer 1

Hi,
in your code example you take the attributes of the element at the start of the current selection. Then you remove all elements to make the attribute set empty. The same can be achieved by a single line of code: AttributeSet set = new SimpleAttributeset(); creating an empty AttributeSet.
Then you apply the empty attribute set to the document with method setCharacterAttributes. Although you pass true in the 'replace' parameter of method setCharacterAttributes, this will not work because 'replace' only replaces explicit settings. I.e. when in the document there is a bold setting, the attribute set must have an attibute such as CSS.Attribute.FONT_WEIGHT set to 'normal' to overwrite the existing bold attribute. In your example, exisiting attributes are kept.
If you like to 'clear' any attributes from a range of text by passing an empty attribute set, you'd have to iterate through the affected elements within the selected text range and apply the empty attribute set explicitly to every element.
This can be done by subclassing HTMLDocument and adding a method as follows  /**
   * apply a set of attributes to a given document element
   * @param e  the element to apply attributes to
   * @param a  the set of attributes to apply
  public void addAttributes(Element e, AttributeSet a) {
    if ((e != null) && (a != null)) {
      try {
        writeLock();
        int start = e.getStartOffset();
        DefaultDocumentEvent changes = new DefaultDocumentEvent(start,
            e.getEndOffset() - start, DocumentEvent.EventType.CHANGE);
        AttributeSet sCopy = a.copyAttributes();
        MutableAttributeSet attr = (MutableAttributeSet) e.getAttributes();
        changes.addEdit(new AttributeUndoableEdit(e, sCopy, false));
        attr.addAttributes(a);
        changes.end();
        fireChangedUpdate(changes);
        fireUndoableEditUpdate(new UndoableEditEvent(this, changes));
      finally {
        writeUnlock();
  } When you iterate through every element in a given selection and call above method with an empty attribute set for each of the elements, all styles will be cleared and the range is reset to default settings. Ulrich