why this component access is multiplying?

[arun mahajan]

Hello,
I have made the followin program and facing this problem. Whenever I click at go of Login screen it adds while printing on system. What i mean if i enter data into id & password and click at go it shows its value first time one time on scrren and in second tme 2 times and third times 3 times..and goes on adding up..
can some body help me WHY?
reagrds,
arun

 
package test;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class test extends JFrame
 implements ActionListener
{
JButton toolbutton;
JToolBar toolbar;
boolean toolbar_flag = true;
makePanel mp = new makePanel();
JMenuBar menubar;
public test()
{
JMenu menu;
JMenuItem menuItem;
Containercont = getContentPane();
cont.setBackground(new Color(140,199,222));
cont.setFont(new Font("arial",Font.BOLD,11));
cont.setLayout(null);
menubar = new JMenuBar();
setJMenuBar(menubar);
//Build File Menu
menu = new JMenu("File");
menu.setMnemonic(KeyEvent.VK_F);
menubar.add(menu);
//Items in File Menu
menuItem = new JMenuItem("Change User/Login",KeyEvent.VK_C);
menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_1, ActionEvent.ALT_MASK));
        menuItem.addActionListener(this);
        menu.add(menuItem);
//adding separator
menu.addSeparator();
menuItem = new JMenuItem("Clear Screen",KeyEvent.VK_S);
menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_2, ActionEvent.ALT_MASK));
        menuItem.addActionListener(this);
        menu.add(menuItem);
//adding separator
menu.addSeparator();
menuItem = new JMenuItem("Exit",KeyEvent.VK_X);
        menuItem.addActionListener(this);
        menu.add(menuItem);
//setting frame size
setSize(450,400);
//setting toolbar
toolbar = new JToolBar();
toolbar.setBackground(new Color(140,199,222));
addToolBarButtons(toolbutton);
toolbar.setBounds(-2,-2,290,30);
toolbar.setFloatable(false);
cont.add(toolbar);
mp.setBounds(0,25,450,375);
cont.add(mp);
mp.cont();
//setting windows listeners
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
        });
//setting frame to a fix size
addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
setSize(450,400);
}
       });
}
protected void addToolBarButtons(JButton jbutton)
{
jbutton = new JButton(new ImageIcon("images/buttons/change_user.gif"));
jbutton.setToolTipText("Change User/Login");
jbutton.addActionListener(this);
toolbar.add(jbutton);
jbutton = new JButton(new ImageIcon("images/buttons/clear.gif"));
jbutton.setToolTipText("Clear Screen");
jbutton.addActionListener(this);
toolbar.add(jbutton);
jbutton = new JButton(new ImageIcon("images/buttons/exit.gif"));
jbutton.setToolTipText("Exit");
jbutton.addActionListener(this);
toolbar.add(jbutton);

}
public void actionPerformed(ActionEvent evt)
{
Object o = evt.getSource();
String s= ""+o;
if(s.indexOf("JMenuItem")>0)
{
s="";
JMenuItem source = (JMenuItem)(evt.getSource());
s = ""+source.getText();
}
else if(s.indexOf("JButton")>0)
{
s="";
JButton source = (JButton)(evt.getSource());
s = ""+source.getToolTipText();
}
//for File Menus
if("Change User/Login".compareToIgnoreCase(s)==0)
{
mp.login(this);
}
else if("Clear Screen".equals(s))
{
mp.clear();
}
else if("Exit".equals(s))
{
System.exit(1);
}
else if((evt.getActionCommand()=="Login"))
{
//calling wait message
mp.clearWithBlue();
//gathering userinformation
String id = mp.pid.getText();
char[] cpwd = mp.ppwd.getPassword();
String pwd="";
for(int i=0;i<cpwd.length;i++)
pwd += ""+cpwd[i];
boolean boxstate = mp.jcb.isSelected();
String xx=""+id+"$"+pwd+"$"+boxstate+"$";
System.out.println("*******"+xx+"*******");

}
}
public static void main(String args[])
{
test ls=new test();
ls.setTitle("test!!");
ls.setVisible(true);
}
}
//class to  handle all the components
class makePanel extends JPanel
{
JLabel label3=null;
JTextField pid =null;
JPasswordField ppwd=null;
JCheckBox jcb = null;
JButton  go = new JButton(new ImageIcon("images/go.gif"));

public makePanel()
{
super();
setLayout(null);
setBackground(new Color(140,199,222));
}
public void cont()
{
JLabel back = new JLabel(new ImageIcon("images/mbg.jpg"));
back.setBounds(112,107,338,218);
add(back);
}
public void login(ActionListener ae)
{
removeAll();
JLabel id = new JLabel();
id.setBounds(142,95,60,20);
id.setText("Login :");
id.setForeground(new Color(255,255,255));
add(id);
JLabel pwd = new JLabel();
pwd.setBounds(115,125,80,20);
pwd.setText("Password :");
pwd.setForeground(new Color(255,255,255));
add(pwd);
pid = new JTextField();
pid.setBounds(200,95,100,20);
add(pid);
ppwd = new JPasswordField();
ppwd.setBounds(200,125,100,20);
ppwd.setEchoChar('*');
add(ppwd);
go.setBounds(295,125,50,20);
go.setForeground(new Color(255,255,255));
go.setOpaque(false);
go.setBorder(null);
go.setActionCommand("Login");
add(go);
go.addActionListener(ae);
jcb = new JCheckBox();
jcb.setBounds(150,155,15,15);
jcb.setBackground(new Color(8,142,206));
add(jcb);

JLabel remPwd = new JLabel();
remPwd.setBounds(170,155,150,20);
remPwd.setText("Remember My ID");
remPwd.setForeground(new Color(255,255,255));
add(remPwd);
JLabel back = new JLabel(new ImageIcon("images/pbg.gif"));
back.setBounds(105,65,231,142);
add(back);
cont();
repaint();
}
public void clear()
{
removeAll();
cont();
repaint();
}
public void clearWithBlue()
{
removeAll();
label3= new JLabel(new ImageIcon("images/wait.gif"));
label3.setBounds(110,75,200,120);
add(label3);
JLabel back = new JLabel(new ImageIcon("images/pbg.gif"));
back.setBounds(105,65,231,142);
add(back);
cont();
repaint();
}
}
 

[Manfred Leonhardt]

Hi Arun,
Your problem stems from the fact that you are recreating the login panel for each call to your login method. But you are not changing the go button. Since your go button is a instance variable you will always have it and every time through your login method you add another listener to the go button.
What you probably want to do is to recreate the go button every time inside the login method. Then you will not be adding more listeners but only one.
Split the definition and initialization of the go button:

JButton go;  // instance variable
//...
public void login( ... )
{
  // ...
  go = new JButton( ... );
  // ...
}

Then all will work as you expect.
Regards,
Manfred.

[arun mahajan]

Thanks a lot for your reply. It works very well.
But after reading your answer it seems this program can be written in better way. Can you spare a moment and let me know how to write in better fashion to get more efficency from this program.
regards,
Arun

[Vinod Venugopal]

Hi Arun,
Your makePanel method was creating the problem, dont call mp = new ..in ur main class.., first of all declare ur memmer variables in main class, then in ur test constructor call methods which will create define the members & create the panels..
test
{
JLabel j;
public test()
{
buildToolbarPanel();
buildMainPanel();
.
.
}
buildMainPanel()
{
j = new JLabel();
....
}
.
.
}
also try not to create a monolithic code for ur actionPerformed(), try as far as possible to use adapter or inner anonymous classes & in each u can call methods so they can be reused, for eg.
login.addActionListener( new ActionListener()
{
public void actionPerfomed(ActionEvent ev)
{
doAction();//u could reuse this doAction
}
});
try to avoid creating unnecessary objects..thats the most common of mistakes as u learn,..
& u will learn more & more tricks by reading Javaranch's code snippets