Runtime Changes to Your GUI

Hello,

Can Swing components be generated dynamically at run time? A simple example would be, a mouse-click inside a Text Field would draw a new Text Field. Again, a mouse-click inside this new Text Field would draw a new Text Field again. There is no limit on number of created Text Fields.

Here they describe how to replace or hide a component but that means that number of components is know during coding (look for Runtime Changes to Your GUI):
http://java.sun.com/docs/books/tutorial/uiswing/layout/group.html

Thank you.

This is a question that comes up a lot. It seems to be a poorly documented aspect of java. I understand it can be done, but i can't tell you how. I'm interested in how this thread turns out.

I would suggest experimenting with an ArrayList<JTextField>. Add a listener to your first one and in the actionPerformed method add a new JTextField to the ArrayList as well as set up it's listener and add it to the panel. Just a thought, I haven't really ever tried to do something like this.

> Can Swing components be generated dynamically at run time?

simple example using buttons

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Testing
{
  int counter = 0;
  JPanel panel = new JPanel();
  public void buildGUI()
  {
    panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
    addButton();
    JButton btn = new JButton("Add Button");
    JFrame f = new JFrame();
    f.getContentPane().add(new JScrollPane(panel));
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.setSize(400,300);
    f.setLocationRelativeTo(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        addButton();
      }
    });
  }
  public void addButton()
  {
    panel.add(new JButton(""+counter));
    counter++;
    panel.revalidate();//these two lines are the most imoportant
    panel.repaint();//must be called when adding to or removing from a visible container
  }
  public static void main(String[] args)
  {
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Testing().buildGUI();
      }
    });
  }
}

using the method I suggested above (and a little free time i had this afternoon) i came up with this as a MouseListener

when i added that to my ArrayList<JTextField> it worked well.