Home » Tip Bank » Application Design » User Interface Design » Controls

Language: Java
Expertise: Intermediate

Mar 4, 2009

This code shows how to create a new event using AWTEventMulticaster.

import java.awt.*;
import java .awt.event.*;

class Buton extends Component{
    private Image button_pressed,button_released;
    private boolean press=false;
     
    ActionListener actionListener;    
    
    public Buton(){

        button_pressed=Toolkit.getDefaultToolkit().getImage("?"); //pressed button
        button_released=Toolkit.getDefaultToolkit().getImage("?"); //released button
                
        MediaTracker mt = new MediaTracker(this);
        mt.addImage(button_pressed,0);mt.addImage(button_released,1);
        try {
              mt.waitForAll(); 
             } catch (InterruptedException e) 
                     {System.out.println(e.getMessage()); }
        enableEvents( AWTEvent.MOUSE_EVENT_MASK );
        setSize( button_pressed.getWidth(null),button_pressed.getHeight(null) );     
        }
        
        public Dimension getPreferredSize(){
        return getSize();
        }
        
    public void paint(Graphics g){
        if(press)g.drawImage(button_pressed,0,0, this);      
        if(!press)g.drawImage(button_released,0,0,this);       
        }

    public void update(Graphics g){paint(g);}

    public void processEvent(AWTEvent e){
        if (e.getID()==MouseEvent.MOUSE_PRESSED){
            press=true;repaint();
        }
        if (e.getID()==MouseEvent.MOUSE_RELEASED){
            press=false;repaint();Event();
        }
        super.processEvent(e);
    }
    
    public void addActionListener(ActionListener l){
        actionListener=AWTEventMulticaster.add(actionListener, l);
    }
    public void removeActionListener(ActionListener l){
        actionListener=AWTEventMulticaster.remove(actionListener, l);
    }
    private void Event(){
        if (actionListener!=null){
            ActionEvent t=new ActionEvent(this,ActionEvent.ACTION_PERFORMED,"press");
            actionListener.actionPerformed(t);
        }
    }
}