Java Swing, 2nd Edition

The ImageIcon Class

Swing provides a concrete implementation of the Icon interface that is considerably more useful than our OvalIcon class. ImageIcon uses a java.awt.Image object to store and display any graphic and provides synchronous image loading (i.e., the Image is loaded completely before returning), making ImageIcons very powerful and easy to use. You can even use an ImageIcon to display an animated GIF89a, making the ubiquitous “animation applet” as simple as this:

// AnimationApplet.java
//
import javax.swing.*;

// A simple animation applet
public class AnimationApplet extends JApplet {
  public void init( ) {
    ImageIcon icon = new ImageIcon("images/rolling.gif");  // Animated gif
    getContentPane( ).add(new JLabel(icon));
  }
}

All we did here was load an animated GIF in the init( ) method and then add it to the applet. For more information on JApplet, see Chapter 8.

ImageIcon currently supports the JPEG, GIF (including animation and transparency), PNG, and XBM image formats. TIFF support should be coming soon. SVG might be supported eventually.

Properties

The ImageIcon class defines the properties listed in Table 4-4. The description property allows an arbitrary description of the image to be specified. One possible use of this property might be to give a blind user an audio description of the image.

Table 4-4. ImageIcon properties

Property	Data type	get	is	set	Default value
description	String	·		·	null
iconHeight o	int	·			-1
iconWidth o	int	·			-1
image	Image	·		·	null
imageLoadStatus	int	·			0
imageObserver ...