whats wrong with my code ?

[naved momin]

what i want to do the button's text should change to the text written in actionperformed method ...but how to implement ?

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package guidemo1;

import java.awt.event.ActionEvent;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;


/**
 *
 * @author Admin
 */
public class GuiDemo1 {

    /**
     * @param args the command line arguments
     */
    JButton button ;
   JFrame frame ;

   GuiDemo1()
    {
       button = new JButton( " OK !");
       frame = new JFrame(" my frame ");
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       frame.setVisible(true);
       button.addActionListener(new ButtonAction() );
      

     }

   void getGui()
    {
        
       frame.add(button);


   }
    public static void main(String[] args) {
        // TODO code application logic here
        GuiDemo1 d = new GuiDemo1();
        d.getGui();

    }

}

class ButtonAction  implements ActionListener
{


    public void actionPerformed(ActionEvent e) {
        button.setText(" ok has been pressed ! ");
        //System.out.println(" hi ok ");
    }
}

[Mohamed Sanaulla]

Your ButtonAction doesn't have the reference to the button on which it has to perform the action. One way is to pass the button reference to the ButtonAction so that the same can be accessed in the actionPerformed method.

[mike ryan]

Hi,

Well for one thing in your ButtonAction method, you will need to find out first if the "Button", is being pressed .You can either set an ActionCommand OR get the source of the current Action.


if(get the source.equals(some source)){

do something;

}

or
if(get some ActionCommand.equals("some ActionCommand")){

do something;

}

Hope that helps a bit .

Mike

[naved momin]

mike ryan wrote:Hi,

Well for one thing in your ButtonAction method, you will need to find out first if the "Button", is being pressed .You can either set an ActionCommand OR get the source of the current Action.


if(get the source.equals(some source)){

do something;

}

or
if(get some ActionCommand.equals("some ActionCommand")){

do something;

}

Hope that helps a bit .

Mike

i didnt understand both of you ,
1. first how can i pass a button to actionperformed method ???

[Darryl Burke]

Naved, please UseAMeaningfulSubjectLine. "whats wrong with my code ?" isn't meaningful, and I see the majority of your threads have the very same subject line.

[Mohamed Sanaulla]

You are not passing the button reference to the actionPerformed, instead you declare the JButton as the member variable of the ButtonAction class and in turn your actionPerformed will use that reference.

[mike ryan]

mabe take a look at this link tutorial

[Campbell Ritchie]

mike ryan wrote: . . .You can either set an ActionCommand OR get the source of the current Action. . . .

I believe you should do neither. If you add the Listener to a particualr button, it is linked to that particular button, so neither of those actions is necessary. Nor beneficial. The direct linking is an object-oriented approach.
Source and action commands are not object-oriented.

Never mind that the Java Tutorials uses getSource, the individual class approach NM showed is much better. You jsut ahve to get the reference to the button passed. This is one way to do it:

class ButtonAction  implements ActionListener
{
/* Changes start here */
    private final JButton button;
    public ButtonAction(JButton button)
    {
         this.button = button;
    }
/* Apart from altering the indentation, this following code is unchanged */
    public void actionPerformed(ActionEvent e)
    {
        button.setText(" ok has been pressed ! ");
        //System.out.println(" hi ok ");
    }
}

By the way, that class is inappropriately named. It is a Listener, and its name should end with Listener. ButtonTextChangingActionListener, maybe

[mike ryan]

Hi Campbell,,

Sorry that is the way i am being taught in my course, so that is the way i would have done it. I will have to try your way and see how that works.


Mike

[naved momin]

Campbell Ritchie wrote:

mike ryan wrote: . . .You can either set an ActionCommand OR get the source of the current Action. . . .

I believe you should do neither. If you add the Listener to a particualr button, it is linked to that particular button, so neither of those actions is necessary. Nor beneficial. The direct linking is an object-oriented approach.
Source and action commands are not object-oriented.

Never mind that the Java Tutorials uses getSource, the individual class approach NM showed is much better. You jsut ahve to get the reference to the button passed. This is one way to do it:

class ButtonAction  implements ActionListener
{
/* Changes start here */
    private final JButton button;
    public ButtonAction(JButton button)
    {
         this.button = button;
    }
/* Apart from altering the indentation, this following code is unchanged */
    public void actionPerformed(ActionEvent e)
    {
        button.setText(" ok has been pressed ! ");
        //System.out.println(" hi ok ");
    }
}

By the way, that class is inappropriately named. It is a Listener, and its name should end with Listener. ButtonTextChangingActionListener, maybe

thanks campbell ....
it helps me learning in this way .....