Re: build a browser in java

From:

"onetitfemme" <onetitfemme2005@yahoo.com>

Newsgroups:

comp.lang.java.programmer

Date:

24 Sep 2006 18:42:16 -0700

Message-ID:

<1159148536.867592.209530@b28g2000cwb.googlegroups.com>

I just did a little tweaking with your code, but there is something I
still don't get right, namely:
..
Why is it you can not display "text/html; charset=UTF-8" or
"text/html; charset=GB2312" encoded pages, even if per javadocs:
..
// __
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/JEditorPane.html
// __
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/JEditorPane.html#setPage
// __
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/JEditorPane.html#setContentType
..
text/html: HTML text. The kit used in this case is the class
javax.swing.text.html.HTMLEditorKit which provides HTML 3.2 support.
..
Weren't "text/html; charset=utf-8" encoded pages supported by HTML
3.2? Something like:
..
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
  <title>HTML 3.2 and text/html; charset=utf-8 test</title>
  <meta http-equiv="content-type" content="text/html; charset=utf-8" />
  <meta http-equiv="Content-Style-Type" content="text/css" />
</head>
....
</html>
..
also I don't quite understand what is meant in the specification with:
..
setContentType: public final void setContentType(String type)
..
Sets the type of content that this editor handles. This calls
getEditorKitForContentType, and then setEditorKit if an editor kit can
be successfully located. This is mostly convenience method that can be
used as an alternative to calling setEditorKit directly.
If there is a charset definition specified as a parameter of the
content type specification, it will be used when loading input streams
using the associated EditorKit. For example if the type is specified as
text/html; charset=EUC-JP the content will be loaded using the
EditorKit registered for text/html and the Reader provided to the
EditorKit to load unicode into the document will use the EUC-JP charset
for translating to unicode. If the type is not recognized, the content
will be loaded using the EditorKit registered for plain text,
text/plain.
..
How can you display non-ASCII characters using a basic java-based
browser like this one?
..
// - - - - - - - - - - - THE CODE
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.html.*;

// __
public class Browser00{
private JTextField addressField;
private JTextPane JTxtPn;
// __
private void initComponents(){
  addressField = new JTextField(50);
  JTxtPn = new JTextPane();
// __
  String aCntntEnc;
  aCntntEnc = "text/html; charset=utf-8";
  aCntntEnc = "text/html; charset=GB2312";
  JTxtPn.setContentType(aCntntEnc);
  JTxtPn.setEditable( false );
// __
  addressField.addActionListener( new ActionListener(){
   public void actionPerformed( ActionEvent e ){
    setPage( addressField.getText().trim() );
   }
  });
// __
  JTxtPn.addHyperlinkListener( new HyperlinkListener(){
   public void hyperlinkUpdate( HyperlinkEvent e ){
    if ( e.getEventType() == HyperlinkEvent.EventType.ACTIVATED ){
    if ( e instanceof HTMLFrameHyperlinkEvent ){
     HTMLFrameHyperlinkEvent evt = (HTMLFrameHyperlinkEvent)e;
     HTMLDocument doc = (HTMLDocument)JTxtPn.getDocument();
     doc.processHTMLFrameHyperlinkEvent( evt );
    }
    else{ setPage( e.getURL().toString() ); }
    }
   }
  });
}
// __
public void setPage( String page ){
  try{
   System.out.println("// - - - - - - - - - - - - - - - - - - ");
   System.out.println("// __ page: " + page);
   System.out.println("// __ Before JTxtPn.setPage(): " +
JTxtPn.getEditorKit().getContentType());
   JTxtPn.setPage( page );
   System.out.println("// __ After JTxtPn.setPage(): " +
JTxtPn.getEditorKit().getContentType());
   addressField.setText( page );
  }catch ( Exception ex ){ JOptionPane.showMessageDialog( null,
ex.getMessage()); }
}
// __
private JComponent createAddressPanel(){
  JLabel addressLabel = new JLabel("Address" );
  addressLabel.setDisplayedMnemonic( KeyEvent.VK_A );
  addressLabel.setLabelFor( addressField );

  Box addressPanel = new Box( BoxLayout.X_AXIS );
  addressPanel.add( addressLabel );
  addressPanel.add( Box.createHorizontalStrut(5) );
  addressPanel.add( addressField );

  return addressPanel;
}
// __
private void createAndShowGUI(){
  initComponents();

  JPanel contentPanel = new JPanel( new BorderLayout() );
  JComponent addressPanel = createAddressPanel();
  addressPanel.setBorder( BorderFactory.createEmptyBorder(5,5,5,5) );

  contentPanel.add( addressPanel, BorderLayout.NORTH );
  contentPanel.add( new JScrollPane(JTxtPn), BorderLayout.CENTER );

  JFrame frame = new JFrame("Browser00");
  frame.setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );
  frame.setContentPane( contentPanel );
  frame.pack();
  frame.setVisible(true);
}
// __
public static final void main( String args[] ){
  EventQueue.invokeLater( new Runnable(){
   public void run(){ new Browser00().createAndShowGUI(); }
  });
}
}