Thread: Drawing a selection box using swing

I have written an application with a panel and three buttons. I want to add selection this buttons using the mouse. I mean like we have in Windows on the Desktop. I press the left mouse button and with the movement of the mouse the area selection is growing.

Is there a specific interface in this or do I have it manually call the appropriate methods for event listeners and there draw transparent rectangle? Here is a picture:


So I have a problem when I paint rectangle using event mouse-dragged, button is repainting so user see blinking button. I want to this button don't disapear when I paint rectangle. I think that I need to use glassPane. This is my conception. I have a frame. In frame I add panel with button and I need another panel where I will paint transparent rectangle. I am thinking then my button will not be still repainting. What do you think about this conception. Or maybe someone have another idea. This is code:

   import java.awt.AlphaComposite;
 
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Rectangle2D;
import java.util.Vector;
 
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
 
public class zaznacz extends JPanel implements MouseListener, MouseMotionListener
{
 
 
     Rectangle newLine=null;
     public zaznacz() 
     {
 
            addMouseListener(this);
            addMouseMotionListener(this);
 
        }
 
 
        static class Rectangle {
 
            int x1,y1,x2,y2;
 
            Rectangle(int _x1, int _y1,int _x2, int _y2){
 
                x1=_x1;y1=_y1;x2=_x2;y2=_y2;
            }
 
 
 
             void paint(Graphics g)
             {
 
 
 
                 g.drawRect(x1, y1, x2, y2);
 
 
            }
 
        }
        public void mouseClicked(MouseEvent e) {
 
                }
 
        @Override
        public void mouseEntered(MouseEvent arg0) {
            // TODO Auto-generated method stub
 
        }
        @Override
        public void mouseExited(MouseEvent arg0) {
            // TODO Auto-generated method stub
 
        }
        @Override
        public void mousePressed(MouseEvent e) {
            startPoint=e.getPoint();
            setOpaque(true);
 
            Graphics2D g2 = (Graphics2D)getGraphics();
 
            Rectangle2D prostokat = new Rectangle2D.Double();
            prostokat.setFrameFromDiagonal(e.getPoint().x, e.getPoint().y,startPoint.x, startPoint.y);
            g2.setComposite(AlphaComposite.getInstance(rule, alpha));
            g2.draw(prostokat);
            g2.setColor(Color.BLUE);
            g2.fill(prostokat);
 
 
        }
        @Override
        public void mouseReleased(MouseEvent e) 
        {
            repaint();
 
        }
        Point startPoint;
 
 
        @Override
        public void mouseDragged(MouseEvent e) {
            setOpaque(true);
 
            Graphics2D g2 = (Graphics2D)getGraphics();
            Rectangle2D prostokat = new Rectangle2D.Double();
 
            prostokat.setFrameFromDiagonal(e.getPoint().x, e.getPoint().y,startPoint.x, startPoint.y);
            g2.setComposite(AlphaComposite.getInstance(rule, alpha));
            g2.draw(prostokat);
            g2.setColor(Color.BLUE);
            g2.fill(prostokat);
            paintComponent(g2);
 
 
        }
        @Override
        public void mouseMoved(MouseEvent e) {
 
 
        }
        int rule = AlphaComposite.SRC_OVER;
        float alpha = 0.85F;
 
 
 
 
    public static void main(String[] args) {
 
        EventQueue.invokeLater(new Runnable()
        {
public void run()
            {
                zaznacz rys = new zaznacz();
                JFrame frame = new JFrame();
                JButton Button = new JButton("1");
                JPanel panel = new JPanel();
 
 
 
                panel.add(Button);
                rys.add(panel);
                frame.setSize(400,300);
                frame.setVisible(true);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                panel.setOpaque(false);
 
                frame.add(rys);
 
 
            }
        });
    }
 
}

I know that code is no perfect but almost work. I have a little problem. When I press the mousebutton and dragging my button disapear.


I don't need advise like "your code is wrong". I know that and I want to somebody help me what I must correct. I know that I shouldn't use paintComponent() in mouseEvents but only that way I can paint transparent rectangle. Or maybe you can othet idea how I can draw transparent rectangle. I try and try and I think that i must change mouseDragged method. because when I delete code from this method and only draw rectangle over a button all is ok. But problem is when I need draw rectangle by dragging mouse. I should change paint but I don't have idea how. Maybe I should use glass pane and paint only on glass pane? I need some ideas. Pls help me.

Thx for advise. I do not ignore all my and others posts. I read more info and correct my code. Sorry for crossposts