Re: Question about Sun's TextSamplerDemo in tutorial

From:

"Oliver Wong" <owong@castortech.com>

Newsgroups:

comp.lang.java.help

Date:

Thu, 03 Aug 2006 20:04:03 GMT

Message-ID:

<TEsAg.182777$S61.115733@edtnps90>

"fiziwig" <fiziwig@yahoo.com> wrote in message
news:1154626490.188775.208860@p79g2000cwp.googlegroups.com...

I've stripped the code of the standard TextSampleDemo.java down to the
bare minimum to demonstrate the problem I'm trying to solve. I want a
button in the toolbar that will turn the selected text in the text pane
to bold when it is clicked. I've been beating my head against this
problem for a couple of days now with no luck.

Any help would be deeply appreciated.

--gary

Here's the code of the stripped down demo with the desired toolbar
button added:

I made changes in the program outside of your "???" section, so read the
whole thing carefully.

<SSCCE>
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.JToolBar;
import javax.swing.text.BadLocationException;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;
import javax.swing.text.StyledDocument;

public class TextSamplerDemo extends JPanel {
private String newline = System.getProperty("line.separator");
private JTextPane textPane;

public TextSamplerDemo() {
  setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
  JToolBar toolBar = buildToolbar();
  add(toolBar);

  // Create a text pane.

  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(paneScrollPane);
}

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[i],
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) {
    StyledDocument doc = textPane.getStyledDocument();
    int offset = textPane.getSelectionStart();
    int length = textPane.getSelectionEnd() - offset;
    MutableAttributeSet attr = new SimpleAttributeSet();
    StyleConstants.setBold(attr, true);
    doc.setCharacterAttributes(offset, length, attr, false);
   }
  });
  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();
   }
  });
}
</SSCCE>

    - Oliver