showdocument.java

java applet编程,实现对相关图片声音的调用

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import java.net.MalformedURLException;

public class ShowDocument extends Applet implements ActionListener
{
    AppletContext appletContext;

    TextField urlField;
    Choice choice;
    Button button;

    public void init()
   {
	setLayout( new GridLayout(3,1) );
	appletContext = getAppletContext();
	Panel p1, p2, p3;

	p1 = new Panel();

        	Label label1 = new Label("URL of document to show:", Label.RIGHT);
        	p1.add(label1);

        	urlField = new TextField("http://www.hust.edu.cn", 40);
        	urlField.addActionListener(this);
	p1.add(urlField);

	add(p1);

	p2 = new Panel();

        	Label label2 = new Label("Window/frame to show it in:", Label.RIGHT);
        	p2.add(label2);

        	choice = new Choice();
        	choice.addItem("(browser's choice)"); //don't specify
        	choice.addItem("My Personal Window"); //a window named "My Personal Window"
        	choice.addItem("_blank"); //a new, unnamed window
        	choice.addItem("_self"); 
        	choice.addItem("_parent"); 
        	choice.addItem("_top"); //the Frame that contained this applet
        	p2.add(choice);
	add(p2);

	p3 = new Panel();

        	button = new Button("Show document");
        	button.addActionListener(this);
	p3.add(button);
        	add(p3);
    }

    public void actionPerformed(ActionEvent event)
    {
        String urlString = urlField.getText();
        URL url = null;
        
        try
        {           url = new URL(urlString);
        }catch (MalformedURLException e)
		{
            System.err.println("Malformed URL: " + urlString);
        }

        if (url != null)
       {
            if (choice.getSelectedIndex() == 0)
            {
                appletContext.showDocument(url);
            }
            else
            {
                appletContext.showDocument(url, choice.getSelectedItem());
            }
        }
    }
}