# 3 Re: Creating a web browser in Java
Here's an extremely poor quality, unfinished web browser I started a long time ago. It's not much but it might be a start for you :)import javax.swing.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
public class WebBrowser extends JFrame {
public JPanel
address_panel, window_panel;
public JLabel
address_label;
public JTextField
address_tf;
public JEditorPane
window_pane;
public JScrollPane
window_scroll;
public JButton
address_b;
private Go go = new Go();
public WebBrowser() throws IOException {
// Define address bar
address_label = new JLabel(" address: ", SwingConstants.CENTER);
address_tf = new JTextField("http://www.yahoo.com");
address_tf.addActionListener(go);
address_b = new JButton("Go");
address_b.addActionListener(go);
window_pane = new JEditorPane("http://www.yahoo.com");
window_pane.setContentType("text/html");
window_pane.setEditable(false);
address_panel = new JPanel(new BorderLayout());
window_panel = new JPanel(new BorderLayout());
address_panel.add(address_label, BorderLayout.WEST);
address_panel.add(address_tf, BorderLayout.CENTER);
address_panel.add(address_b, BorderLayout.EAST);
window_scroll = new JScrollPane(window_pane);
window_panel.add(window_scroll);
Container pane = getContentPane();
pane.setLayout(new BorderLayout());
pane.add(address_panel, BorderLayout.NORTH);
pane.add(window_panel, BorderLayout.CENTER);
setTitle("web browser");
setSize(800,600);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public class Go implements ActionListener{
public void actionPerformed(ActionEvent ae){
try {
window_pane.setPage(address_tf.getText());
} catch (MalformedURLException e) { // new URL() failed
window_pane.setText("MalformedURLException: " + e);
} catch (IOException e) { // openConnection() failed
window_pane.setText("IOException: " + e);
}
}
}
public static void main(String args[]) throws IOException {
WebBrowser wb = new WebBrowser();
}
}
# 4 Re: Creating a web browser in Java
Hi,
thanx for the reply
But I done this one already. Using JEditorPane.setPage() method we can develop a web browser, but the problem is that it cannot handle javascript and other scripts. It will not detect textfields in http://www.google.com , That is Google serach. But same thing wors fine with http://www.yahoo.com why?? How can I solve the problem??
Please look at this code.
import javax.swing.*;
import javax.swing.text.*;
import java.awt.event.*;
import java.awt.*;
import java.io.File;
import java.io.*;
import java.util.*;
import javax.swing.event.*;
import javax.swing.text.html.*;
import javax.swing.event.HyperlinkListener;
import javax.swing.event.HyperlinkEvent;
import java.lang.*;
import java.net.*;
import java.net.HttpURLConnection;
public class WebBrowser extends JFrame implements ActionListener,HyperlinkListener
{
private JEditorPane jep;
JTextField urlField;
JButton back = new JButton("",new ImageIcon("undo.gif"));
final JLabel statusBar = new JLabel(" ");
JButton Go=new JButton("GO");
String url = "";
public WebBrowser(String startingUrl)
{
super("Simple Web Browser : Developed in Java ");
setSize(1035,740);
setDefaultCloseOperation(EXIT_ON_CLOSE);
Container con=getContentPane();
JPanel urlPanel = new JPanel();
urlPanel.setLayout(new BorderLayout());
urlField = new JTextField(startingUrl);
urlPanel.add(new JLabel("Site: "), BorderLayout.WEST);
urlPanel.add(urlField);
urlPanel.add(Go,BorderLayout.EAST);
Go.addActionListener(this);
urlField.addActionListener(this);
jep = new JEditorPane();
jep.setEditable(false);
jep.setEditorKit(new HTMLEditorKit());
jep.setContentType("text/html");
JScrollPane jsp = new JScrollPane(jep);
getContentPane().add(jsp, BorderLayout.CENTER);
getContentPane().add(urlPanel, BorderLayout.NORTH);
getContentPane().add(statusBar, BorderLayout.SOUTH);
jep.addHyperlinkListener(new SimpleLinkListener(jep, urlField,statusBar));
}
public void actionPerformed(ActionEvent ae)
{
Object obj=ae.getSource();
String url1="http://www.rediff.com";
if(obj==urlField)
{
try
{
url=ae.getActionCommand();
url1=URLDecoder.decode(url);
jep.setPage(url);
}catch(Exception e){statusBar.setText("Error: " + e.getMessage());}
}
if(obj==Go)
{
try
{
jep.setPage(urlField.getText());
}catch(Exception e){statusBar.setText("Error: " + e.getMessage());}
}
}
public void hyperlinkUpdate(HyperlinkEvent e)
{
if(e.getEventType() == HyperlinkEvent.EventType.ACTIVATED)
{
jep = (JEditorPane) e.getSource();
try
{
jep.setPage(e.getURL());
}catch (Throwable t){t.printStackTrace();}
}
}
public static void main(String args[])
{
//Setting the proxy if needed.
/*System.getProperties().put("proxySet","true");
System.getProperties().put("proxyPort","8080");
System.getProperties().put("proxyHost","192.168.2.1");*/
String url = "";
url = "about:blank";
new WebBrowser(url).setVisible(true);
}
public class SimpleLinkListener implements HyperlinkListener
{
private JEditorPane pane;
private JTextField urlField;
private JLabel statusBar;
public SimpleLinkListener(JEditorPane jep, JTextField jtf, JLabel jl)
{
pane = jep;
urlField = jtf;
statusBar = jl;
}
public SimpleLinkListener(JEditorPane jep)
{
this(jep, null, null);
}
public void hyperlinkUpdate(HyperlinkEvent he)
{
HyperlinkEvent.EventType type = he.getEventType();
if (type == HyperlinkEvent.EventType.ENTERED)
{
if (statusBar != null)
{
statusBar.setText(he.getURL().toString());
}
}
else if(type == HyperlinkEvent.EventType.EXITED)
{
if(statusBar != null)
{
statusBar.setText(" ");
}
}
else if (type == HyperlinkEvent.EventType.ACTIVATED)
{
try
{
pane.setPage(he.getURL());
if (urlField != null)
{
jep.setPage(he.getURL());
urlField.setText(he.getURL().toString());
}
}
catch (FileNotFoundException fnfe){pane.setText("Could not open file: <tt>" + he.getURL() + "</tt>.<hr>");}
catch (Exception e){e.printStackTrace();}
}
}
}
}
Please tell me how can I fix the problems??
Thank You
Waiting for your reply
Sandeep Kumar K
Email : sandeepkk2005@rediffmail.com
# 6 Re: Creating a web browser in Java
HI MAN I CAN ALSO HELP AND HAVE GOT A SOLUTION FOR U TRY IT AND TELL ME MAN
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.html.*;
// The Mini Web Browser.
public class MiniBrowser extends JFrame
implements HyperlinkListener
{
// These are the buttons for iterating through the page list.
private JButton backButton, forwardButton;
// Page location text field.
private JTextField locationTextField;
// Editor pane for displaying pages.
private JEditorPane displayEditorPane;
// Browser's list of pages that have been visited.
private ArrayList pageList = new ArrayList();
// Constructor for Mini Web Browser.
public MiniBrowser()
{
// Set application title.
super("Mini Browser");
// Set window size.
setSize(640, 480);
// Handle closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionExit();
}
});
// Set up file menu.
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
JMenuItem fileExitMenuItem = new JMenuItem("Exit",
KeyEvent.VK_X);
fileExitMenuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionExit();
}
});
fileMenu.add(fileExitMenuItem);
menuBar.add(fileMenu);
setJMenuBar(menuBar);
// Set up button panel.
JPanel buttonPanel = new JPanel();
backButton = new JButton("< Back");
backButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionBack();
}
});
backButton.setEnabled(false);
buttonPanel.add(backButton);
forwardButton = new JButton("Forward >");
forwardButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionForward();
}
});
forwardButton.setEnabled(false);
buttonPanel.add(forwardButton);
locationTextField = new JTextField(35);
locationTextField.addKeyListener(new KeyAdapter() {
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
actionGo();
}
}
});
buttonPanel.add(locationTextField);
JButton goButton = new JButton("GO");
goButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionGo();
}
});
buttonPanel.add(goButton);
// Set up page display.
displayEditorPane = new JEditorPane();
displayEditorPane.setContentType("text/html");
displayEditorPane.setEditable(false);
displayEditorPane.addHyperlinkListener(this);
getContentPane().setLayout(new BorderLayout());
getContentPane().add(buttonPanel, BorderLayout.NORTH);
getContentPane().add(new JScrollPane(displayEditorPane),
BorderLayout.CENTER);
}
// Exit this program.
private void actionExit() {
System.exit(0);
}
// Go back to the page viewed before the current page.
private void actionBack() {
URL currentUrl = displayEditorPane.getPage();
int pageIndex = pageList.indexOf(currentUrl.toString());
try {
showPage(
new URL((String) pageList.get(pageIndex - 1)), false);
}
catch (Exception e) {}
}
// Go forward to the page viewed after the current page.
private void actionForward() {
URL currentUrl = displayEditorPane.getPage();
int pageIndex = pageList.indexOf(currentUrl.toString());
try {
showPage(
new URL((String) pageList.get(pageIndex + 1)), false);
}
catch (Exception e) {}
}
// Load and show the page specified in the location text field.
private void actionGo() {
URL verifiedUrl = verifyUrl(locationTextField.getText());
if (verifiedUrl != null) {
showPage(verifiedUrl, true);
} else {
showError("Invalid URL");
}
}
// Show dialog box with error message.
private void showError(String errorMessage) {
JOptionPane.showMessageDialog(this, errorMessage,
"Error", JOptionPane.ERROR_MESSAGE);
}
// Verify URL format.
private URL verifyUrl(String url) {
// Only allow HTTP URLs.
if (!url.toLowerCase().startsWith("http://"))
return null;
// Verify format of URL.
URL verifiedUrl = null;
try {
verifiedUrl = new URL(url);
} catch (Exception e) {
return null;
}
return verifiedUrl;
}
/* Show the specified page and add it to
the page list if specified. */
private void showPage(URL pageUrl, boolean addToList)
{
// Show hour glass cursor while crawling is under way.
setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
try {
// Get URL of page currently being displayed.
URL currentUrl = displayEditorPane.getPage();
// Load and display specified page.
displayEditorPane.setPage(pageUrl);
// Get URL of new page being displayed.
URL newUrl = displayEditorPane.getPage();
// Add page to list if specified.
if (addToList) {
int listSize = pageList.size();
if (listSize > 0) {
int pageIndex =
pageList.indexOf(currentUrl.toString());
if (pageIndex < listSize - 1) {
for (int i = listSize - 1; i > pageIndex; i--) {
pageList.remove(i);
}
}
}
pageList.add(newUrl.toString());
}
// Update location text field with URL of current page.
locationTextField.setText(newUrl.toString());
// Update buttons based on the page being displayed.
updateButtons();
}
catch (Exception e)
{
// Show error messsage.
showError("Unable to load page");
}
finally
{
// Return to default cursor.
setCursor(Cursor.getDefaultCursor());
}
}
/* Update back and forward buttons based on
the page being displayed. */
private void updateButtons() {
if (pageList.size() < 2) {
backButton.setEnabled(false);
forwardButton.setEnabled(false);
} else {
URL currentUrl = displayEditorPane.getPage();
int pageIndex = pageList.indexOf(currentUrl.toString());
backButton.setEnabled(pageIndex > 0);
forwardButton.setEnabled(
pageIndex < (pageList.size() - 1));
}
}
// Handle hyperlink's being clicked.
public void hyperlinkUpdate(HyperlinkEvent event) {
HyperlinkEvent.EventType eventType = event.getEventType();
if (eventType == HyperlinkEvent.EventType.ACTIVATED) {
if (event instanceof HTMLFrameHyperlinkEvent) {
HTMLFrameHyperlinkEvent linkEvent =
(HTMLFrameHyperlinkEvent) event;
HTMLDocument document =
(HTMLDocument) displayEditorPane.getDocument();
document.processHTMLFrameHyperlinkEvent(linkEvent);
} else {
showPage(event.getURL(), true);
}
}
}
// Run the Mini Browser.
public static void main(String[] args) {
MiniBrowser browser = new MiniBrowser();
browser.show();
}
}
shamshami@yahoo.com