clickable line

[Ravi Gupta]

hi all

I would like to know if there is a way to make a line that connects two buttons clickable? i.e. on being clicked the line should change colour.

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Line2D;
import javax.swing.*;
 
public class Clickables extends JPanel {
    Point selection = new Point(-1,-1);
 
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        Component[] c = getComponents();
        for(int j = 0; j < c.length; j++) {
            Rectangle r = c[j].getBounds();
            double x1 = r.getCenterX();
            double y1 = r.getCenterY();
            for(int k = j+1; k < c.length; k++) {
                r = c[k].getBounds();
                double x2 = r.getCenterX();
                double y2 = r.getCenterY();
                Color color = (j==selection.x && k==selection.y) ? Color.red
                                                                 : Color.blue;
                g2.setPaint(color);
                g2.draw(new Line2D.Double(x1, y1, x2, y2));
            }
        }
    }
 
    public static void main(String[] args) {
        Clickables test = new Clickables();
        test.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.weightx = 1.0;
        test.add(new JButton("Button 1"), gbc);
        test.add(new JButton("Button 2"), gbc);
        test.addMouseListener(test.ml);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(test);
        f.setSize(400,200);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private MouseListener ml = new MouseAdapter() {
        final int S = 6;
        Rectangle sensor = new Rectangle(S,S);
 
        public void mousePressed(MouseEvent e) {
            Point p = e.getPoint();
            sensor.setFrameFromCenter(p.x, p.y, p.x+S/2, p.y+S/2);
            Container source = (Container)e.getComponent();
            Component[] c = source.getComponents();
            for(int j = 0; j < c.length; j++) {
                Rectangle r = c[j].getBounds();
                double x1 = r.getCenterX();
                double y1 = r.getCenterY();
                for(int k = j+1; k < c.length; k++) {
                    r = c[k].getBounds();
                    double x2 = r.getCenterX();
                    double y2 = r.getCenterY();
                    if(new Line2D.Double(x1,y1,x2,y2).intersects(sensor)) {
                        if(selection.x == j && selection.y == k)
                            selection.setLocation(-1,-1);  // toggle off
                        else
                            selection.setLocation(j, k);   // set values
                        source.repaint();
                        return;
                    }
                }
            }
        }
    };
}