Getting the label of a JButton in a for loop

Question

hi,
I doing a project for my course at the minute and im in need of a bit of help. I have set up 1-d array of buttons and i have layed them out using a for loop. I have also added an annoymous action listener to each button in the loop. It looks something lke this:
b = new JButton[43];
for (int i=1; i<43; i++)
b[i] = new JButton(" ");
b.addActionListener(
new ActionListener()
public void actionPerformed(ActionEvent e)
          System.out.println("..........");
}); // addActionListener
} // for
I want the "System.out.println( ..." line, to print out the "i" number of the button that was pressed but i cannot figure out how to do it. I cannot put "System.out.println(" "+i);" as it wont recognise i as it is not inside the for loop. Does anyone have any suggestions?
Thanks!!

Answer 1

class ButtonExample extends JFrame implements ActionListener{The OP wanted to have anonymous listeners, not a subclassed JFrame
listening to the buttons. I don't know if the following is the best design,
since the poster has revealed so little, but here is how to pass the
loop index to an anonymous class.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ButtonExample {
    private JButton[] buttons = new JButton[24];
    public JPanel createGUI() {
        JPanel gui = new JPanel(new GridLayout(6,  4));
        for(int i=0; i<buttons.length; i++) {
            final int ii = i; //!! !
            buttons[i] = new JButton("button #" + i);
            buttons.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt) {
System.out.println("number " + ii);
gui.add(buttons[i]);
return gui;
public static void main(String[] args) {
ButtonExample app = new ButtonExample();
JPanel gui = app.createGUI();
JFrame f = new JFrame("ButtonExample");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(gui);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);