swing - get component clicked on JPanel

问题:

OK so I've got a JPanel with a GridLayout. Each cell of the grid then contains another JPanel.

What I'd like to be able to do is have a listener on the "underneath" JPanel which then tells me which of the "overlayed" JPanels was clicked - so I can react to it and the surrounding ones, without making the covering JPanels aware of their position (they change!!)

Is there a way of doing this - similar to Determine clicked JPanel component in the MouseListener. Event handling but I couldn't find a way of grabbing the component on top.

I could probably grab the co-oridnates and work it out using that info - but I'd rather not!!

Any help/pointers/tips would be appreciated :D

回答1:

Do the same thing but use getParent() on the source. Or you can search up the hierarchy if it is deeper, even some helper methods for that: javax.swing.SwingUtilities.getAncestorOfClass and getAncestorNamed

回答2:

use putClientProperty / getClientProperty, nothing simplest around ..., you can put endless numbers of ClientProperty to the one Object

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;

public class MyGridLayout {

    public MyGridLayout() {
        JPanel bPanel = new JPanel();
        bPanel.setLayout(new GridLayout(10, 10, 2, 2));
        for (int row = 0; row < 10; row++) {
            for (int col = 0; col < 10; col++) {
                JPanel b = new JPanel();
                System.out.println("(" + row + ", " + col + ")");
                b.putClientProperty("column", row);
                b.putClientProperty("row", col);
                b.addMouseListener(new MouseAdapter() {

                    @Override
                    public void mouseClicked(MouseEvent e) {
                        JPanel btn = (JPanel) e.getSource();
                        System.out.println("clicked column " + btn.getClientProperty("column")
                                + ", row " + btn.getClientProperty("row"));
                    }
                });
                b.setBorder(new LineBorder(Color.blue, 1));
                bPanel.add(b);
            }
        }
        JFrame frame = new JFrame("PutClientProperty Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(bPanel);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                MyGridLayout myGridLayout = new MyGridLayout();
            }
        });
    }
}