GridLayout + Mouse Listener

Question

Okay guys I have a problem, I dont know how know which cell was clicked on a grid layout, is there any function?

I have grid layout on container, for 10 rows and 10 columns, and what I want is a mouse listener to all the cells, so when I click cell (2,1) it would say which cell I am clicking because of the mouse listener.

Any clues? thanks alot in advance

Answer 1

Add a MouseListener to the Container that uses GridLayout and that holds the components in the grid. Then on mousePressed use the MouseEvent object, say called myMouseEvent, to get the point of the click and call getComponentAt(myMouseEvent.getPoint); to get the clicked component. No muss no fuss.

For example:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;

public class TestComponentAt extends JPanel {
   private static final int ROW_COUNT = 10;
   private static final int W = 60;
   private static final int H = W;
   private static final Dimension PREF_SIZE = new Dimension(W, H);
   protected static final Color SELECTION_COLOR = Color.pink;
   private JPanel selectedPanel = null;
   private Color originalColor = null;

   public TestComponentAt() {
      setLayout(new GridLayout(ROW_COUNT, ROW_COUNT, 1, 1));
      setBackground(Color.black);
      for (int i = 0; i < ROW_COUNT * ROW_COUNT; i++) {
         JPanel panel = new JPanel();
         String name = String.format("[%d, %d]", 
               i / ROW_COUNT, i % ROW_COUNT);
         panel.setName(name);
         if (i == 0) {
            originalColor = panel.getBackground();
         }
         panel.setPreferredSize(PREF_SIZE);
         add(panel);
      }
      addMouseListener(new MouseAdapter() {
         @Override
         public void mousePressed(MouseEvent e) {
            JPanel panel = (JPanel) getComponentAt(e.getPoint());
            if (panel == null || panel == TestComponentAt.this) {
               return;
            }
            if (selectedPanel != null) {
               selectedPanel.setBackground(originalColor);
               selectedPanel.removeAll();
               selectedPanel.revalidate();
               selectedPanel.repaint();
            }
            selectedPanel = panel;
            selectedPanel.setBackground(SELECTION_COLOR);
            selectedPanel.add(new JLabel(selectedPanel.getName()));
            selectedPanel.revalidate();
            selectedPanel.repaint();
         }
      });
   }

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

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}