The Java Boutique: Step by Step Java Tutorial

Tutorials : Step by Step :
Chapter 1 :

Contents

Graphical Interface

Hello World Example

Drawing Shapes and using colors

Displaying Images

Using basic components

Layout of GUI

Displaying Images

/*
This applet will display a gif on screen
for now the gif file must be in the same directory as this applet
*/

import java.awt.*;
import java.applet.*;
// These classes are for Url's.
import java.net.*;

public class ImageExample extends Applet
{
// Your image name;
Image my_gif;

// The applet base URL
URL base;

// This object will allow you to control loading
MediaTracker mt;

     public void init()
     {

// initialize the MediaTracker
          mt = new MediaTracker(this);

// The try-catch is necessary when the URL isn't valid
// Of course this one is valid, since it is generated by
// Java itself.

         try {
   // getDocumentbase gets the applet path.
               base = getDocumentBase();
         }
         catch (Exception e) {}

// Here we load the image.
// Only Gif and JPG are allowed. Transparent gif also.
          my_gif = getImage(base,"imageExample.gif");

// tell the MediaTracker to keep an eye on this image, and give it ID 1;
          mt.addImage(my_gif,1);

// now tell the mediaTracker to stop the applet execution
// (in this example don't paint) until the images are fully loaded.
// must be in a try catch block.

         try {
               mt.waitForAll();
          }
          catch (InterruptedException e) {}

// when the applet gets here then the images is loaded.

     }

     public void paint(Graphics g)
     {
// now we are going to draw the gif on the screen
// (image name,x,y,observer);

          g.drawImage(my_gif,20,20,this);

// you can resize the image easily

g.drawImage(my_gif,20,140,30,40,this);

}

// That's all. Images can also be drawn without the mediaTracker but then
// the screen will flicker.
// a base URL variable is also not necessary but when you have lots of images to load
// then it's shorter to type.

// Next is the basic GUI (Graphical User Interface) components.

Next...

Applet Index
(sorted alphabetically)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z #s

The Java Source
(applets w/source code)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z

How to Add Java Applets to Your Site

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