Border of JPanel with mouseEvent handling

Question

How to create a border of JPanel, which will be able to handle MouseEvents?

I tried to do something like that:

abstract public class MyBorder extends LineBorder implements MouseListener

But after implementing virtual methods I cannot assign mouseListener to my class. I guess, that I have to assign it into some JComponent.

So, how can I create some sort of border with mouseListener?

Answer 1

Here is an SSCCE that supports that borders get mouse events on the component to which they are applied.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.LineBorder;

class BorderListener {

    private void initGui() {
        final JPanel gui = new JPanel();
        gui.setBackground(Color.green);
        gui.setPreferredSize(new Dimension(300,50));
        gui.setBorder(new LineBorder(Color.blue, 10));
        gui.addMouseListener( new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent me) {
                System.out.println(me.getPoint());
            }
        });
        JOptionPane.showMessageDialog(null, gui);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                BorderListener bl = new BorderListener();
                bl.initGui();
            }
        });
    }
}

Typical Output

When clicking in the wide border assigned to this panel, you might see output along these lines.

java.awt.Point[x=8,y=3]
java.awt.Point[x=3,y=26]
java.awt.Point[x=1,y=43]
java.awt.Point[x=15,y=6]
java.awt.Point[x=101,y=5]
java.awt.Point[x=220,y=4]
java.awt.Point[x=287,y=5]
java.awt.Point[x=295,y=3]
Press any key to continue . . .

The border is 10px wide, so if (x||y < 10), it is within the line border.

---

Update

(Comment to camickr, which also applied to my answer)

Yes but then this mouseListener will be added for the whole JPanel. Not only for my Border. Am I wrong?

Just ignore the event if it happens in the non-border area of the panel.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.LineBorder;

class BorderListener {

    private void initGui() {
        final JPanel gui = new JPanel();
        gui.setBackground(Color.yellow);
        gui.setPreferredSize(new Dimension(300,50));
        gui.setBorder(new LineBorder(Color.orange, 15));
        gui.addMouseListener( new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent me) {
                int w = gui.getWidth();
                int h = gui.getHeight();
                int x = me.getPoint().x;
                int y = me.getPoint().y;
                Insets ins = gui.getInsets();
                boolean inBorder =
                    ( x<ins.left ||
                    x>w-ins.right ||
                    y<ins.top ||
                    y>h-ins.bottom);
                if (inBorder) {
                    System.out.println(me.getPoint());
                } else {
                    System.out.println("Ignore!");
                }
            }
        });
        JOptionPane.showMessageDialog(null, gui);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                BorderListener bl = new BorderListener();
                bl.initGui();
            }
        });
    }
}

Output

java.awt.Point[x=168,y=7]
Ignore!
java.awt.Point[x=164,y=41]
java.awt.Point[x=297,y=39]
java.awt.Point[x=297,y=21]
Ignore!
Ignore!
java.awt.Point[x=2,y=21]
Press any key to continue . . .

Answer 2

A MouseListener must be added to a Component, not a Border. So to use your class the code would need to be something like:

Border border = new MyBorder();
panel.setBorder( border );
panel.addMouseListener( border );