TextSamplerDemo.java question

Question

I took the TextSamplerDemo from http://java.sun.com/docs/books/tutorial/uiswing/components/text.html and stripped it down to the one thing I have a question about. Given the code below, how do I implement the toolbar button to make selected text turn bold? I've been beating my head againt this one for a couple of days now and getting nowhere.
Any help would be deeply appeciated.
--gary
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*; //for layout managers and more
import java.awt.event.*; //for action events
public class TextSamplerDemo extends JPanel
implements ActionListener {
private String newline = "\n";
protected static final String textFieldString = "JTextField";
public TextSamplerDemo() {
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
JToolBar toolBar = buildToolbar();
add(toolBar);
//Create a text pane.
JTextPane textPane = createTextPane();
JScrollPane paneScrollPane = new JScrollPane(textPane);
paneScrollPane.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
paneScrollPane.setPreferredSize(new Dimension(250, 155));
paneScrollPane.setMinimumSize(new Dimension(10, 10));
add(textPane);
public void actionPerformed(ActionEvent e) {
private JTextPane createTextPane() {
String[] initString =
{ "This is an editable JTextPane, ",            //regular
"another ", //italic
"styled ", //bold
"text ", //small
"component, " + newline, //large
"which supports embedded components..." + newline,//regular
newline + "JTextPane is a subclass of JEditorPane that " + newline +
"uses a StyledEditorKit and StyledDocument, and provides " + newline +
"cover methods for interacting with those objects."
String[] initStyles =
{ "regular", "italic", "bold", "small", "large",
"regular", "regular"
JTextPane textPane = new JTextPane();
StyledDocument doc = textPane.getStyledDocument();
addStylesToDocument(doc);
try {
for (int i=0; i < initString.length; i++) {
doc.insertString(doc.getLength(), initString,
doc.getStyle(initStyles[i]));
} catch (BadLocationException ble) {
System.err.println("Couldn't insert initial text into text pane.");
return textPane;
protected void addStylesToDocument(StyledDocument doc) {
//Initialize some styles.
Style def = StyleContext.getDefaultStyleContext().
getStyle(StyleContext.DEFAULT_STYLE);
Style regular = doc.addStyle("regular", def);
StyleConstants.setFontFamily(def, "SansSerif");
Style s = doc.addStyle("italic", regular);
StyleConstants.setItalic(s, true);
s = doc.addStyle("bold", regular);
StyleConstants.setBold(s, true);
s = doc.addStyle("small", regular);
StyleConstants.setFontSize(s, 10);
s = doc.addStyle("large", regular);
StyleConstants.setFontSize(s, 16);
private JToolBar buildToolbar() {
JToolBar toolBar = new JToolBar();
toolBar.setRollover( true );
toolBar.setFloatable( false );
JButton boldButton = new JButton("Bold");
boldButton.setToolTipText( "Set selected text to bold" );
boldButton.addActionListener( new ActionListener() {
public void actionPerformed( ActionEvent e ) {
// code here to make selected text bold
toolBar.add( boldButton );
return toolBar;
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
//Create and set up the window.
JFrame frame = new JFrame("TextSamplerDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new TextSamplerDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();

Answer 1

try this, but im'not sure.
StyleContext styleContext = StyleContext.getDefaultStyleContext();
Style def = styleContext.getStyle(StyleContext.DEFAULT_STYLE);
Style bold = styledDocument.addStyle("bold", def);
StyleConstants.setBold(bold, true);into the listener of your component insert this:
int start = getSelectionStart();
int len = getSelectionEnd() - start;
styledDocument.setCharacterAttributes(start, len, bold, true);by gino