Determine clicked JPanel component in the MouseListener. Event handling

The MouseEvent#getSource method will return which object has been clicked:

public class MouseAdapterMod extends MouseAdapter {

   // usually better off with mousePressed rather than clicked
   public void mousePressed(MouseEvent e) {
       ButtonPanel btnPanel = (ButtonPanel)e.getSource();
       btnPanel.setButtonText();
   }
}

As the comments note, you’re often better off listening for mousePressed or mouseReleased rather than mouseClicked because for mouseClicked to work, the press and release must be from the same point, and if the mouse shifts even a slight amount, the click won’t register.

My test program:

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.*;

import javax.swing.*;

public class MainForButtonPanel extends JPanel {
   public MainForButtonPanel() {
      setLayout(new GridLayout(4, 4));

      MouseAdapter myMA = new MouseAdapterMod();

      for (int i = 0; i < 4; i++) {
         for (int j = 0; j < 4; j++) {
            ButtonPanel btnPanel = new ButtonPanel();
            btnPanel.addMouseListener(myMA);
            add(btnPanel);
         }
      }

   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("MainForButtonPanel");
      frame.getContentPane().add(new MainForButtonPanel());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

class ButtonPanel extends JPanel {

   private static final int TIMER_DELAY = 2000;
   private static final String JUST_CLICKED = "just clicked";
   private static final String WAITING_FOR_CLICK = "waiting for click";
   private static final Color CLICKED_COLOR = Color.pink;
   private JLabel label;

   public ButtonPanel() {
      label = new JLabel(WAITING_FOR_CLICK);
      add(label);
   }

   public void setButtonText() {
      label.setText(JUST_CLICKED);
      setBackground(CLICKED_COLOR);

      new Timer(TIMER_DELAY, new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            label.setText(WAITING_FOR_CLICK);
            setBackground(null);
            ((Timer)ae.getSource()).stop();
         }
      }).start();
   }

}

class MouseAdapterMod extends MouseAdapter {

   // usually better off with mousePressed rather than clicked
   public void mousePressed(MouseEvent e) {
       ButtonPanel btnPanel = (ButtonPanel)e.getSource();
       btnPanel.setButtonText();
   }
}