Plz help me in my code

Question

Hi all Plz tell me why 2D lines are not drawn here by clicking on "make connection" JButton and then on required JButtons to make connection between them........................................................................................................
Plz tell me the reason .......................................... I don't know why u all silent....................................... here is code.....................................................
..................................................plz be hurry in replying.....................................
...................................................thanx in advance..........................................
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Line2D;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.MouseInputAdapter;
public class Connections3
ConnectionsPanel connectionsPanel;
public Connections3()
connectionsPanel = new ConnectionsPanel();
JFrame f = new JFrame("Connection");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(getUIPanel(), "North");
f.getContentPane().add(connectionsPanel);
f.setSize(400,300);
f.setLocation(200,200);
f.setVisible(true);
private Box getUIPanel()
JButton connect = new JButton("make connection");
connect.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e)
connectionsPanel.selectingButtonsForConnection = true;
Box box = Box.createHorizontalBox();
box.setBorder(BorderFactory.createEmptyBorder(2,0,2,0));
box.add(Box.createHorizontalGlue());
box.add(connect);
box.add(Box.createHorizontalGlue());
box.add(Box.createHorizontalGlue());
return box;
public static void main(String[] args)
new Connections3();
class ConnectionsPanel extends JPanel
{ ButtonMover mover;
JButton button1, button2, button3,button4;
JButton[] buttons;
Component selectedButton;
//int offsetX, offsetY;
boolean dragging, selectingButtonsForConnection;
Point start;
List<Component[]> connections;
public ConnectionsPanel()
{ mover=new ButtonMover(this);
dragging = false;
selectingButtonsForConnection = false;
connections = new ArrayList<Component[]>();
setOpaque(false);
setLayout(null);
addButtons();
addMouseListener(new ButtonSelector());
addMouseMotionListener(mover);
public void paintComponent(Graphics g)
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(Color.blue);
for(int j = 0; j < connections.size(); j++)
Component[] pair = connections.get(j);
Point p1 = getCenter(pair[0]);
Point p2 = getCenter(pair[1]);
g2.draw(new Line2D.Double(p1.x, p1.y, p2.x, p2.y));
private Point getCenter(Component c)
Rectangle r = c.getBounds();
return new Point((int)r.getCenterX(), (int)r.getCenterY());
private class ButtonSelector extends MouseAdapter
Component[] components;
boolean haveSelection;
public ButtonSelector()
haveSelection = false;
public void mousePressed(MouseEvent e)
Point p = e.getPoint();
for(int j = 0; j < buttons.length; j++)
Rectangle r = buttons[j].getBounds();
if(r.contains(p))
if(selectingButtonsForConnection)
if(!haveSelection)
components = new Component[2];
components[0] = buttons[j];
else
components[1] = buttons[j];
if(components[0] != components[1])
connections.add(components);
selectingButtonsForConnection = false;
repaint();
haveSelection = !haveSelection;
else // selecting for dragging
selectedButton = buttons[j];
/* selectedButton = (JButton)e.getSource();
start = e.getPoint();*/
dragging = true;
/* offsetX = p.x - r.x;
offsetY = p.y - r.y;
dragging = true;*/
break;
public void mouseReleased(MouseEvent e)
dragging = false;
class ButtonMover extends MouseInputAdapter
ConnectionsPanel connectionPanel;
public ButtonMover(ConnectionsPanel cp)
connectionPanel = cp;
dragging = false;
public void mousePressed(MouseEvent e)
selectedButton = (JButton)e.getSource();
start = e.getPoint();
dragging = true;
public void mouseReleased(MouseEvent e)
dragging = false;
public void mouseDragged(MouseEvent e)
if(dragging)
Point end = e.getPoint();
int x = selectedButton.getX() + end.x - start.x;
int y = selectedButton.getY() + end.y - start.y;
Rectangle r = selectedButton.getBounds();
selectedButton.setBounds(x, y,r.width,r.height);
repaint();
private void addButtons()
int w = 125;
int h = 25;
Border border = BorderFactory.createEtchedBorder();
button1 = new JButton("Button 1");
button2 = new JButton("Button 2");
button3 = new JButton("Button 3");
button4 = new JButton("Button 4");
buttons = new JButton[4];
buttons[0] = button1;
buttons[1] = button2;
buttons[2] = button3;
buttons[3] = button4;
for(int j = 0; j < buttons.length; j++)
buttons[j].setBorder(border);
buttons[j].setOpaque(true);
// buttons[j].setBackground(Color.white);
buttons[j].addMouseListener(mover);
buttons[j]. addMouseMotionListener(mover);
add(buttons[j]);
// buttons[j].addActionListener()
button1.setBounds(40, 40, w, h);
button2.setBounds(215, 40, w, h);
button3.setBounds(40, 200, w, h);
button4.setBounds(215, 200, w, h);
}

Answer 1

Hey im not quite shure what you mean, do you want to press make connection then press 2 buttons to make a connection between them? you might wanna clear it up, some people are to lazy to corrrect your code. but i did waht i could and here it is. but holy crap if that is what your doing, its a mess of code. i would suggest taking another shot at it, sometimes if it doesnt go good the first time try again. good luck.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Line2D;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.MouseInputAdapter;
public class Connections3
     ConnectionsPanel connectionsPanel;
     public Connections3()
          connectionsPanel = new ConnectionsPanel();
          JFrame f = new JFrame("Connection");
          f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          f.getContentPane().add(getUIPanel(), "North");
          f.getContentPane().add(connectionsPanel);
          f.setSize(400,300);
          f.setLocation(200,200);
          f.setVisible(true);
     private Box getUIPanel()
          JButton connect = new JButton("make connection");
          connect.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent e)
                    connectionsPanel.selectingButtonsForConnection = true;
          Box box = Box.createHorizontalBox();
          box.setBorder(BorderFactory.createEmptyBorder(2,0,2,0));
          box.add(Box.createHorizontalGlue());
          box.add(connect);
          box.add(Box.createHorizontalGlue());
          box.add(Box.createHorizontalGlue());
          return box;
     public static void main(String[] args)
          new Connections3();
class ConnectionsPanel extends JPanel
     ButtonMover mover;
     JButton button1, button2, button3,button4;
     JButton[] buttons;
     Component selectedButton;
     //int offsetX, offsetY;
     boolean dragging, selectingButtonsForConnection;
     Point start;
     ArrayList connections;
     public ConnectionsPanel()
          mover=new ButtonMover(this);
          dragging = false;
          selectingButtonsForConnection = false;
          connections = new ArrayList();
          setOpaque(false);
          setLayout(null);
          addButtons();
          addMouseListener(new ButtonSelector());
          addMouseMotionListener(mover);
     public void paintComponent(Graphics g)
          super.paintComponent(g);
          Graphics2D g2 = (Graphics2D)g;
          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
               RenderingHints.VALUE_ANTIALIAS_ON);
          g2.setPaint(Color.blue);
          /* Fixed some Errors with your Component[], converting regular to array
          Not possible, also your loop would go from 0 - list.size and you are accesing
          j through j+1, so your gonna get a index out of bounds */          
          Component pair;
          for(int j = 0; j < connections.size()-1; j++)
               pair = (Component)connections.get(j);
               Point p1 = getCenter(pair);
               pair = (Component)connections.get(j+1);
               Point p2 = getCenter(pair);
               g2.draw(new Line2D.Double(p1.x, p1.y, p2.x, p2.y));
     private Point getCenter(Component c)
          Rectangle r = c.getBounds();
          return new Point((int)r.getCenterX(), (int)r.getCenterY());
     private class ButtonSelector extends MouseAdapter
          Component[] components;
          boolean haveSelection;
          public ButtonSelector()
               haveSelection = false;
     public void mousePressed(MouseEvent e)
          Point p = e.getPoint();
          for(int j = 0; j < buttons.length; j++)
               Rectangle r = buttons[j].getBounds();
               if(r.contains(p))
                    if(selectingButtonsForConnection)
                         if(!haveSelection)
                              components = new Component[2];
                              components[0] = buttons[j];
                         else
                              components[1] = buttons[j];
                              if(components[0] != components[1])
                              connections.add(components);
                              selectingButtonsForConnection = false;
                              repaint();
                         haveSelection = !haveSelection;
                    else // selecting for dragging
                         selectedButton = buttons[j];
                         /* selectedButton = (JButton)e.getSource();
                         start = e.getPoint();*/
                         dragging = true;
                         /* offsetX = p.x - r.x;
                         offsetY = p.y - r.y;
                         dragging = true;*/
                         break;
     public void mouseReleased(MouseEvent e)
          dragging = false;
     class ButtonMover extends MouseInputAdapter
          ConnectionsPanel connectionPanel;
          public ButtonMover(ConnectionsPanel cp)
               connectionPanel = cp;
               dragging = false;
          public void mousePressed(MouseEvent e)
               selectedButton = (JButton)e.getSource();
               start = e.getPoint();
               dragging = true;
          public void mouseReleased(MouseEvent e)
               dragging = false;
               public void mouseDragged(MouseEvent e)
                    if(dragging)
                         Point end = e.getPoint();
                         int x = selectedButton.getX() + end.x - start.x;
                         int y = selectedButton.getY() + end.y - start.y;
                         Rectangle r = selectedButton.getBounds();
                         selectedButton.setBounds(x, y,r.width,r.height);
                         repaint();
     private void addButtons()
          int w = 125;
          int h = 25;
          Border border = BorderFactory.createEtchedBorder();
          button1 = new JButton("Button 1");
          button2 = new JButton("Button 2");
          button3 = new JButton("Button 3");
          button4 = new JButton("Button 4");
          buttons = new JButton[4];
          buttons[0] = button1;
          buttons[1] = button2;
          buttons[2] = button3;
          buttons[3] = button4;
          for(int j = 0; j < buttons.length; j++)
               buttons[j].setBorder(border);
               buttons[j].setOpaque(true);
               // buttons[j].setBackground(Color.white);
               buttons[j].addMouseListener(mover);
               buttons[j]. addMouseMotionListener(mover);
               add(buttons[j]);
               // buttons[j].addActionListener()
          button1.setBounds(40, 40, w, h);
          button2.setBounds(215, 40, w, h);
          button3.setBounds(40, 200, w, h);
          button4.setBounds(215, 200, w, h);
}