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Introduction to Swing Applet

Posted in : Core Java Posted on : October 30, 2010 at 5:42 PM Comments : [ 0 ]

This section contains the detail about the basic operators in java.

Introduction to Swing Applet

Any applet that contains Swing components must be implemented with a subclass of JApplet. JApplet is a subclass of java.applet.Applet .

Example

In this example, We embed a Swing applet into web browser. This applet contains two buttons, when you click on any one of it, it shows which one is clicked.

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 
 
public class SwingApplet extends JApplet { 
  JButton jbtnOne; 
  JButton jbtnTwo; 
 
  JLabel jlab; 
 
  public void init() { 
    try { 
      SwingUtilities.invokeAndWait(new Runnable () { 
        public void run() { 
          guiInit(); // initialize the GUI 
        } 
      }); 
    } catch(Exception exc) { 
      System.out.println("Can't create because of "+ exc); 
    } 
  } 
 
  // Called second, after init().  Also called 
  // whenever the applet is restarted.  
  public void start() { 
    // Not used by this applet. 
  } 
 
  // Called when the applet is stopped. 
  public void stop() { 
    // Not used by this applet. 
  } 
 
  // Called when applet is terminated.  This is 
  // the last method executed. 
  public void destroy() { 
    // Not used by this applet. 
  } 
 
  // Setup and initialize the GUI.  
  private void guiInit() { 
    // Set the applet to use flow layout. 
    setLayout(new FlowLayout()); 
 
    // Create two buttons and a label. 
    jbtnOne = new JButton("One"); 
    jbtnTwo = new JButton("Two"); 
 
    jlab = new JLabel("Press a button."); 
 
    // Add action listeners for the buttons. 
    jbtnOne.addActionListener(new ActionListener() {      
      public void actionPerformed(ActionEvent le) {  
        jlab.setText("Button One pressed.");  
      }      
    });      
 
    jbtnTwo.addActionListener(new ActionListener() {      
      public void actionPerformed(ActionEvent le) {  
        jlab.setText("Button Two pressed.");  
      }      
    });      
 
    // Add the components to the applet's content pane. 
    getContentPane().add(jbtnOne); 
    getContentPane().add(jbtnTwo); 
    getContentPane().add(jlab);     
  } 
}

For invoking it into a browser, the following Html code is needed :

<html>
<title>The Applet Demo</title>
<hr>
<applet code="SwingApplet.class" width=240 height=100> 
This message only appears if your browser is not java enabled or there is some error.
</applet>
<hr>
</html>