Have an ImageButtonTag(s): AWT


This implementation of an ImageButton requires JDK1.1 and is a good example of the new Event architecture. This ImageButton needs 2 GIF images representing the normal and pressed state (  ). Also a method to disable the button by using a special filter is given.

[ImageButton.java]
import java.awt.*;
 import java.awt.event.*;
 import java.awt.image.*;
 import java.net.*;

 public class ImageButton extends Canvas {
   protected ActionListener actionListener = null;
   int w,h;
   boolean clicked;
   boolean down;
   boolean enabled;
   Image UPimage;
   Image DOWNimage;
   Image disabledimage;

   public ImageButton(URL up_b, URL down_b) {
     clicked=false;
     down=false;
     enabled=true;
     InitImage(up_b,down_b);
     setSize(w,h);
     addMouseListener(new ImageButtonMouseListener());
     addMouseMotionListener(new ImageButtonMouseMotionListener());
     }

   public void InitImage(URL up, URL down) {
     MediaTracker tracker;
     try {
       UPimage = getToolkit().getImage(up);
       DOWNimage = getToolkit().getImage(down);
       tracker = new MediaTracker(this);
       tracker.addImage(UPimage,0);
       tracker.addImage(DOWNimage,1);
       tracker.waitForAll();
       } 
     catch (InterruptedException e) {
       e.printStackTrace();
       }
     disabledimage=createImage(new FilteredImageSource
       (UPimage.getSource(),new ImageButtonDisableFilter()));
     w=UPimage.getWidth(this);
     h=UPimage.getHeight(this);
     }

   public void paint(Graphics g) {
     if (down) {
       g.drawImage(DOWNimage,0,0,this);
       } 
     else {
       if (enabled) {
         g.drawImage(UPimage,0,0,this);
         } 
       else {
         g.drawImage(disabledimage,0,0,this);
         }
       }
     }

   public void setEnabled(boolean b) {
     enabled=b;
     repaint();
     }

   public boolean isEnabled() {
     return (enabled);
     }

   public void addActionListener(ActionListener l) {
     actionListener = 
        AWTEventMulticaster.add(actionListener,l);
     }
   public void removeActionListener(ActionListener l) {
     actionListener =
        AWTEventMulticaster.remove(actionListener, l);
     }

   public class ImageButtonMouseListener extends MouseAdapter {
     public void mousePressed(MouseEvent e) {
       Point p = e.getPoint();
       if ((p.x < w)&&(p.y < h)&&(p.x > 0)&&(p.y > 0)&&(enabled==true)) {
         clicked=true;
         down=true;
         repaint();
         }
       }
     public void mouseReleased(MouseEvent e) {
       Point p = e.getPoint();
       if (down) {
         down=false;
         repaint();
         }
       if ((p.x < w)&&(p.y < h)&&(p.x > 0)&&(p.y > 0)&&(clicked==true)) {
         ActionEvent ae = 
           new ActionEvent(e.getComponent(),0,"click");
         if (actionListener != null) {
           actionListener.actionPerformed(ae);
           }
         }
       clicked=false;
       }
     }
   public class ImageButtonMouseMotionListener extends
       MouseMotionAdapter {
     public void mouseDragged(MouseEvent e) {
       Point p = e.getPoint();
       if ((p.x < w)&&(p.y < h)&&(p.x > 0)&&(p.y > 0)&&(clicked==true)) {
         if (down==false) {
           down=true;
           repaint();
           }
         } 
       else {
         if (down==true) {
           down=false;
           repaint();
           }
         }
       }
     }

   public Dimension getPreferredSize() {
     return (new Dimension(UPimage.getWidth(this),
             UPimage.getHeight(this)));
     }

   public Dimension getMinimumSize() {
     return getPreferredSize();
     }

   class ImageButtonDisableFilter extends RGBImageFilter {
      public ImageButtonDisableFilter() {
        canFilterIndexColorModel=true;
        }
      public int filterRGB(int x, int y, int rgb) {
        return (rgb & ~0xff000000) | 0x80000000;
        }
      }
}
[TestImageButton.java]
 import java.awt.*;
 import java.awt.event.*;
 import java.applet.*;
 import java.net.*;


 public class TestImageButton extends Applet
   implements ActionListener,ItemListener {
   ImageButton ib;
   Checkbox c;  

   public void init() {
     setLayout(new FlowLayout());
     try {
       ib = new ImageButton
               (new URL(getCodeBase(), "Gumby.gif"), 
                new URL(getCodeBase(), "Gumbyblu.gif"));
       c = new Checkbox("disable");
       ib.addActionListener(this);
       c.addItemListener(this);
       add(ib);
       add(c);
       }
     catch (Exception e) {
       e.printStackTrace();
       }
     }

   public void actionPerformed(ActionEvent e) {
     if (e.getSource() == ib) System.out.println("Click ImageButton");
     }

   public void itemStateChanged(ItemEvent ie) {
     ib.setEnabled(!ib.isEnabled());
     }
}

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