The Bold Attribute won't stay bold ?

Question

Hi,
I've for a JTextPane in which I can type text, I press enter is takes a new line etc.
I also have a JButton which I've called "SetBold", and when I press this button this code line is implemented
            new StyledEditorKit.BoldAction().actionPerformed(null);Seems to work ok, when I highlight text and press the button if changes it to bold, and when no text is highlighted and I press the button, the next text I type is bold and I can press it again to do the opposite. As the java site says, its a "toggle for the bold attribute".
Problem is, if I press it, and type stuff and it appears bold. If I press backspace until all the text is deleted and start typing again, it has "toggled itself off" for some reason.
I don't want it to do that.
I want to know when the attribute is set so I can change the color of the button to notify the user that bold is set. But I can't even do this, as by monitoring the attribute (through System.out.println) it is always false on the largest/fartherst caret position (as if it is saying, there is nothing in the next space as its blank, therefore attribute is false for this space), until you type a charactor, then it changes true ! So I therefore cannot tell, whether or not the next letter I type will be bold or not.
Can anyone suggest a method of knowing when, the next letter I type, whether it will be bold or not ? This will allow me to know what color to set the JButton.
As I say, the isBold() method doesn't seem helpful for this objective.
Thanks for your help/

Answer 1

Hopefully I'm doing something wrong, but it doesn't work for me. Unfortunately, I couldn't get it to work either. The method doesn't work the way I would expect it to. I was able to get it working a little better than you but it still doesn't work completely. I ended up borrowing code from the JTextPane.getCharacterAttributes() method:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
public class TextPaneCaret extends JFrame implements CaretListener
     JTextPane textPane;
     public TextPaneCaret()
          textPane = new JTextPane();
          textPane.addCaretListener( this );
          JScrollPane scrollPane = new JScrollPane( textPane );
          scrollPane.setPreferredSize( new Dimension( 200, 200 ) );
          getContentPane().add( scrollPane );
          JButton bold = new JButton( new StyledEditorKit.BoldAction() );
          getContentPane().add(bold, BorderLayout.SOUTH);
     public void caretUpdate(CaretEvent e)
          StyledDocument doc = textPane.getStyledDocument();
          int offset = textPane.getCaretPosition();
          if (offset > 0)
               offset--;
          Element run = doc.getCharacterElement(offset);
          AttributeSet attributes = run.getAttributes();
//          AttributeSet attributes = textPane.getInputAttributes();
          System.out.println( attributes.containsAttribute(StyleConstants.Bold, Boolean.TRUE) );
     public static void main(String[] args)
          TextPaneCaret frame = new TextPaneCaret();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setVisible(true);
}The above code works after text has been typed, but it doesn't register the bold attribute until at least one character has been typed with the attribute. Example:
a) enter "abc"
b) click bold
c) enter "123"
Move caret around it will correctly display the attribute of the next character to be typed.
d) move to end of text
e) click bold
This is where it gets tricky.
If you just move the caret between the Bold characters and then move to the end of the text a "normal" character will be entered.
However, if you move the caret between the bold and normal characters and then move to the end of the text a "bold" character will be entered. Its like it lost the information that you have a "pending" normal character to enter.
Totally confusing me and I have no idea how to fix it. It looks the the only way to be 100% sure what the attribute will be is to enter the character and remove it as you have proposed.
As you can see I also did some testing with getInputAttributes. This is because I traced the DefaultEditorKit DefaultKeyTypedAction back to the replaceSelection() method of JTextPane. This method just uses a insertString(...., , getInputAttributes()). Again these attributes are correct immediately after you click on the bold button, but if you move the caret before entering any text then its possible that these attributes will change to match the attributes at the new location of the cursor. Hope that makes some sense. Anyway, I've given up.