ActionEvent

[Al Finlay]

I would like to understand the sequence involved here -

Netbeans auto-generated code stub for a button named convert

private void convertButtonActionPerformed(java.awt.event.ActionEvent evt)

where is the code that generates the ActionEvent object passed to this method?

[Darryl Burke]

Drop the visual designer. As you're discovering, it's not a beginners' tool.

Go through this tutorial: How to Write an Action Listener.

[Al Finlay]

Sorry I'm not explaining myself very well. Take this small example:

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;

/**
 *
 * @author Alistair
 */
public class MouseSensor extends JFrame
{

    private JTextField tf;

    public MouseSensor()
    {
        setTitle("Mouse sensor");
        setSize(400, 100);
        setLocation(100, 100);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        tf = new JTextField("Waiting for mouse activity");
        tf.addMouseListener(new MouseWatcher());
        tf.addKeyListener(new KeyWatcher());
        getContentPane().add(tf);
    }

    private class MouseWatcher extends MouseAdapter
    {
        @Override
        public void mouseEntered(MouseEvent e)
        {
            tf.setText("I sense the presense of a mouse");
        }

        @Override
        public void mouseExited(MouseEvent e)
        {
            tf.setText("The mouse has gone now. Press Enter to reset the text");
        }
    }

    private class KeyWatcher extends KeyAdapter
    {
        public void keyPressed(KeyEvent e)
        {
            if (e.getKeyCode()==KeyEvent.VK_ENTER)
            {
                tf.setText("Waiting for mouse activity"); 
            }
        }
    }
}

The code in itself does not reveal the mechanics of what is actually happening here. It reminds me of jQuery functions .. but I can understand that because I can look at the underlying jQuery scripts.
Is the JVM automatically catching all events and passing them to any available methods? Is there no intermediary code?

[Steve Luke]

Al Finlay wrote:Is the JVM automatically catching all events and passing them to any available methods? Is there no intermediary code?

The events are triggered in the JTextField, or some parent of the JTextField. The code is part of core Java, you will probably find it in the src.zip file (found inside your JDK folder). It might requires some digging though.