Re: Applet - Creating new objects from a Button Listener

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 22 Apr 2007 16:34:41 -0700
Message-ID:
<miSWh.8202$2Q1.7400@newsfe16.lga>
theneb wrote:

Hello everyone, I'm attempting to create JComponents from when a
button is clicked. However I'm assuming I'm missing something? (Or
it's not possible)

This is some quick prototype code which shows my intentions.

import java.awt.*;
import javax.swing.*;
import java.applet.*;
import java.awt.event.*;
import java.util.*;

public class myApplet extends Applet implements ActionListener{

    private JPanel buttonPanel;
    private HashMap<String,testButton> buttons;

    private testButton myButton, secondButton, thirdButton;

    public void init(){
        buttonPanel = new JPanel();
        buttons = new HashMap<String,testButton>();
        buttons.put(String.valueOf(buttons.size()),new testButton());
        buttonPanel.add(buttons.get(String.valueOf(buttons.size()-1)));
        add(buttonPanel);
    }//end init

    public void start(){
        System.out.println("START");
    }

    public void actionPerformed(ActionEvent event) {
        System.out.println("Action");
    }

private class testButton extends JButton implements ActionListener{

    public testButton(){
        setText("Button "+buttons.size());
        addActionListener(this);
    }

    public void actionPerformed(ActionEvent event) {
        System.out.println("Adding New Button");
        buttons.put(String.valueOf(buttons.size()),new testButton());
        buttonPanel.add(buttons.get(String.valueOf(buttons.size()-1)));
    }

}

}//end myApplet

Example here: http://www.theneb.co.uk/applet-test/test.html

Cheers


After you add or remove components from a container you need to call
validate() and usually repaint(). This will cause the LayoutManager to
re-layout your components. If your containers are JComponents (which
JApplet is not) you can call revalidate() on the container to have the
LayoutManager re-layout the component.

Also, you are using JButtons and an Applet. You should not mix AWT and
Swing components. If you are going to use JButtons, use a JApplet.

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

public class test extends JApplet {
     public void init() {
         setLayout(new FlowLayout());

         JButton add = new JButton("Add a Button");
         add.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent ae) {
                 test.this.add(new Tutton("Press Me"));
                 test.this.validate();
                 test.this.repaint();
             }
         });
         add(add);
     }

     class Tutton extends JButton implements ActionListener {
         public Tutton(String text) {
             super(text);
             addActionListener(this);
         }
         public void actionPerformed(ActionEvent ae) {
             test.this.remove((JComponent)ae.getSource());
             test.this.validate();
             test.this.repaint();
         }
     }
}

--

Knute Johnson
email s/nospam/knute/

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