How to handle an action event

1. Specify that the class that contains the button implements the ActionListener interface:

class FutureValuePanel extends JPanel implements ActionListener

2. Add an ActionListener object to the button by calling the addActionListener method:

exitButton.addActionListener(this);

3. Implement the ActionListener interface by coding the actionPerformed method:

public void actionPerformed(ActionEvent e)
{
   Object source = e.getSource();
   if (source == exitButton)
      System.exit(0);
}
		

A panel class that handles two action events

class FutureValuePanel extends JPanel implements ActionListener
{
    private JButton calculateButton;
    private JButton exitButton;

    public FutureValuePanel()
    {
        calculateButton = new JButton("Calculate");
        calculateButton.addActionListener(this); // add an action listener
        this.add(calculateButton);

        exitButton = new JButton("Exit");
        exitButton.addActionListener(this); // add an action listener
        this.add(exitButton);
    }

    public void actionPerformed(ActionEvent e)
    {
        Object source = e.getSource();
        if (source == exitButton)
            System.exit(0);
        else if (source == calculateButton)
            calculateButton.setText("Clicked!");
    }
}