Core Swing Components - The Definitive Guide to Java Swing - page 93

ImageIcon Properties
Table 4-10 shows the six properties of ImageIcon . The height and width of the ImageIcon are the
height and width of the actual Image object. The imageLoadStatus property represents the results of
the loading of the ImageIcon from the hidden MediaTracker , either MediaTracker.ABORTED ,
MediaTracker.ERRORED , or MediaTracker.COMPLETE .

Table 4-10. ImageIcon Properties
Property Name

Data Type Access

description String

Read-write

iconHeight int Read-only

iconWidth int Read-only

image Image

Read-write

imageLoadStatus int Read-only

imageObserver ImageObserver Read-write

Sometimes, it's useful to use an ImageIcon to load an Image , and then just ask for the Image
object from the Icon .

ImageIcon imageIcon = new ImageIcon(...);
Image image = imageIcon.getImage();

There is one major problem with using ImageIcon objects: They don't work when the
image and class file using the icon are both loaded in a JAR (Java archive) file, unless you explicitly
specify the full URL for the file within the JAR ( jar:http://www.example.com/directory/
foo.jar!/com/example/image.gif ). You can't just specify the file name as a String and let the
ImageIcon find the file. You must manually get the image data first, and then pass the data
along to the ImageIcon constructor.
To help with loading images outside JAR files, Listing 4-4 shows an ImageLoader class that
provides a public static Image getImage(Class relativeClass, String filename) method.
You specify both the base class where the image file relative is found and the file name for the
image file. Then you just need to pass the Image object returned to the constructor of ImageIcon .

Listing 4-4. Image Loading Support Class

import java.awt.*;
import java.io.*;

public final class ImageLoader {

private ImageLoader() {
}