java - 向图形添加功能

Question

这是我的代码，我想向我制作的矩形添加功能，例如当您单击它时，会弹出一个窗口

public class codetwo extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        this.setBackground(Color.LIGHT_GRAY);
        g.setColor(Color.RED);
        g.fillRect(110,110, 120, 120);
    }

    public static void main(String args[]) {
        codetwo cd = new codetwo(); 
        JFrame frame = new JFrame("Title");
        frame.add(cd);
        frame.setSize(440,350);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

Answer 1

为此，您需要使用 Mouselistener。

public class codetwo extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        this.setBackground(Color.LIGHT_GRAY);
        g.setColor(Color.RED);
        g.fillRect(110,110, 120, 120);
    }

    public static void main(String args[]) {
        codetwo cd = new codetwo(); 
cd.addMouseListener(new MouseListener(){

            @Override
            public void mouseClicked(MouseEvent e) {
                // TODO Auto-generated method stub
                if  (e.getX() >= 110 && e.getX() <= 230 && e.getY() >= 110 && e.getY() <= 230) { 
                    JOptionPane.showMessageDialog(cd, "Some one clicked here ?", "Listening", JOptionPane.INFORMATION_MESSAGE);
                }
            }

            @Override
            public void mousePressed(MouseEvent e) {
                // TODO Auto-generated method stub

            }

            @Override
            public void mouseReleased(MouseEvent e) {
                // TODO Auto-generated method stub

            }

            @Override
            public void mouseEntered(MouseEvent e) {
                // TODO Auto-generated method stub

            }

            @Override
            public void mouseExited(MouseEvent e) {
                // TODO Auto-generated method stub

            }
        JFrame frame = new JFrame("Title");
        frame.add(cd);
        frame.setSize(440,350);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}