java gui graphics problem

what i'm trying to do is everytime i click, a square should come up in the Jpanel, but for some reason the Jpanel is blocking the squares(click on the edges). I'm really not sure what i did wrong, thanks for your help!

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class VIewa extends JFrame implements ActionListener {

    JRadioButton[]      buttons;
    JRadioButton[]      colorBut;
    JButton             colorButton;
    JPanel     blankArea; 
    panel ppp;
    public VIewa(String title) {

        super(title);
        try {
            UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
            } catch (Exc开发者_如何学运维eption e) {}
        setLayout(new FlowLayout());

        add(new JLabel("shapes:"));
        ButtonGroup     operations = new ButtonGroup();
        buttons = new JRadioButton[8];
        buttons[0] = new JRadioButton("line", false);
        buttons[1] = new JRadioButton("FillRec", false);
        buttons[2] = new JRadioButton("HolRec", false);
        buttons[3] = new JRadioButton("FilCir", false);
        buttons[4] = new JRadioButton("HolCir", false);
        buttons[5] = new JRadioButton("FilPol", false);
        buttons[6] = new JRadioButton("HolPol", false);
        buttons[7] = new JRadioButton("Text", false);
        for (int i=0; i<8; i++) {
            add(buttons[i]);
            operations.add(buttons[i]);
            buttons[i].addActionListener(this);
        }
        add(new JLabel("colors:"));
        ButtonGroup     colo = new ButtonGroup();
        colorBut = new JRadioButton[8];
        colorBut[0] = new JRadioButton("red", false);
        colorBut[1] = new JRadioButton("orange", false);
        colorBut[2] = new JRadioButton("yellow", false);
        colorBut[3] = new JRadioButton("green", false);
        colorBut[4] = new JRadioButton("blue", false);
        colorBut[5] = new JRadioButton("black", false);
        colorBut[6] = new JRadioButton("gray", false);
        colorBut[7] = new JRadioButton("white", false);
        for (int i=0; i<8; i++) {
            add(colorBut[i]);
            colo.add(colorBut[i]);
            colorBut[i].addActionListener(this);
        }
        add(new JLabel("current color:"));
        colorButton = new JButton();
        add(colorButton); 
        ppp = new panel();
        add(ppp);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(600,670);
    }

    public class panel extends JPanel implements MouseListener {

        private ArrayList<Point>  squares;
        public panel(){
              squares = new ArrayList<Point>(); 
            JPanel     blankArea;
            blankArea = new JPanel(); 
            blankArea.setLayout(null); 
            //blankArea.setOpaque(true); 
            blankArea.setBorder(BorderFactory.createLineBorder(Color.black)); 
            blankArea.setPreferredSize(new Dimension(450, 550)); 
            addMouseListener(this); 
            add(blankArea);
        }
        public void paintComponent(Graphics graphics) { 
            super.paintComponent(graphics);

            graphics.setColor(Color.black);
            for (Point center: squares)
                graphics.drawRect(center.x - 20, center.y - 20, 40, 40); 
        }
        public void mouseClicked(MouseEvent arg0) {}
        public void mouseEntered(MouseEvent arg0) {}
        public void mouseExited(MouseEvent arg0) {}
        public void mousePressed(MouseEvent event) {
            squares.add(event.getPoint()); 
            repaint(); }
        public void mouseReleased(MouseEvent arg0) {}
    }

    public static void main(String args[]) {
        JFrame frame = new VIewa("Graphics");
        JPanel framex = new JPanel(); 
        framex.add(new SquareCanvas()); 
        framex.setVisible(true); 
        frame.setVisible(true);
    }
    public void actionPerformed(ActionEvent arg0) {
    }
}

try this code. I just removed your 'blankArea' panel..

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

class VIewa extends JFrame implements ActionListener {

JRadioButton[] buttons;
JRadioButton[] colorBut;
JButton colorButton;
JPanel blankArea;
panel ppp;

public VIewa(String title) {

    super(title);
    try {
        UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
    } catch (Exception e) {
    }
    setLayout(new FlowLayout());

    add(new JLabel("shapes:"));
    ButtonGroup operations = new ButtonGroup();
    buttons = new JRadioButton[8];
    buttons[0] = new JRadioButton("line", false);
    buttons[1] = new JRadioButton("FillRec", false);
    buttons[2] = new JRadioButton("HolRec", false);
    buttons[3] = new JRadioButton("FilCir", false);
    buttons[4] = new JRadioButton("HolCir", false);
    buttons[5] = new JRadioButton("FilPol", false);
    buttons[6] = new JRadioButton("HolPol", false);
    buttons[7] = new JRadioButton("Text", false);
    for (int i = 0; i < 8; i++) {
        add(buttons[i]);
        operations.add(buttons[i]);
        buttons[i].addActionListener(this);
    }
    add(new JLabel("colors:"));
    ButtonGroup colo = new ButtonGroup();
    colorBut = new JRadioButton[8];
    colorBut[0] = new JRadioButton("red", false);
    colorBut[1] = new JRadioButton("orange", false);
    colorBut[2] = new JRadioButton("yellow", false);
    colorBut[3] = new JRadioButton("green", false);
    colorBut[4] = new JRadioButton("blue", false);
    colorBut[5] = new JRadioButton("black", false);
    colorBut[6] = new JRadioButton("gray", false);
    colorBut[7] = new JRadioButton("white", false);
    for (int i = 0; i < 8; i++) {
        add(colorBut[i]);
        colo.add(colorBut[i]);
        colorBut[i].addActionListener(this);
    }
    add(new JLabel("current color:"));
    colorButton = new JButton();
    add(colorButton);
    ppp = new panel();
    add(ppp);
    ppp.setBorder(BorderFactory.createLineBorder(Color.black));
    ppp.setPreferredSize(new Dimension(450, 550));
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(600, 670);
}

public class panel extends JPanel implements MouseListener {

    private ArrayList<Point> squares;

    public panel() {
        squares = new ArrayList<Point>();
        //JPanel blankArea;
        //blankArea = new JPanel();
        //blankArea.setLayout(null);
        //blankArea.setOpaque(true);
        //blankArea.setBorder(BorderFactory.createLineBorder(Color.black));
        //blankArea.setPreferredSize(new Dimension(450, 550));
        addMouseListener(panel.this);
        //add(blankArea);
    }

    @Override
    public void paintComponent(Graphics graphics) {
        super.paintComponent(graphics);

        graphics.setColor(Color.black);
        for (Point center : squares) {
            graphics.drawRect(center.x - 20, center.y - 20, 40, 40);
        }
    }

    public void mouseClicked(MouseEvent arg0) {
        squares.add(arg0.getPoint());
        repaint();
    }

    public void mouseEntered(MouseEvent arg0) {
    }

    public void mouseExited(MouseEvent arg0) {
    }

    public void mousePressed(MouseEvent event) {
        squares.add(event.getPoint());
        repaint();
    }

    public void mouseReleased(MouseEvent arg0) {
    }
}

public static void main(String args[]) {
    JFrame frame = new VIewa("Graphics");
    JPanel framex = new JPanel();
    JPanel p = new JPanel();
    p.setBounds(new Rectangle(100,50));
    framex.add(p);
    framex.setVisible(true);
    frame.setVisible(true);
}

public void actionPerformed(ActionEvent arg0) {
}
}

but for some reason the Jpanel is blocking the squares

What do you mean, the squares are not visible? This might be because blankArea overlays the parent panel in which you draw the squares.