Problème avec mon application tableau blanc

Question

Je dois développer une application de tableau blanc dans lequel à la fois l'utilisateur local et l'utilisateur distant doivent être able to draw simultaneously, est-ce possible? Si possible, alors toute logique?

Je l'ai déjà développé un code, mais dans lequel je ne suis pas en mesure de le faire, lorsque l'utilisateur distant commence à dessiner la forme que je dessine est remplacée par sa forme et coordonnées. Ce problème est que lorsque les deux tirer simultanément.

any gars idée?

Voici mon code

class  Paper extends JPanel implements MouseListener,MouseMotionListener,ActionListener
{
    static BufferedImage image;
    int bpressed;
    Color color;
    Point start;
    Point end;
    Point mp;
    Button elipse=new Button("elipse");
    Button rectangle=new Button("rect");
    Button line=new Button("line");
    Button empty=new Button("");
    JButton save=new JButton("Save");
    JButton erase=new JButton("Erase");
    String selected;
    int ex,ey;//eraser
    DatagramSocket dataSocket;
    JButton button = new JButton("test");
    Client client;
    Point p=new Point();
    int w,h;
    public Paper(DatagramSocket dataSocket) 
    {        
        this.dataSocket=dataSocket;
        client=new Client(dataSocket);
        System.out.println("paper");
        setBackground(Color.white);
        addMouseListener(this);
        addMouseMotionListener(this);
        color = Color.black; 
        setBorder(BorderFactory.createLineBorder(Color.black));         
        //save.setPreferredSize(new Dimension(100,20));
        save.setMaximumSize(new Dimension(75,27));
        erase.setMaximumSize(new Dimension(75,27));
    }

    public  void paintComponent(Graphics g) 
    {
        try
        {
        g.drawImage(image, 0, 0, this);
        Graphics2D g2 = (Graphics2D)g;
        g2.setPaint(Color.black);
        if(selected==("elipse"))
            g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y));
        else if(selected==("rect"))
            g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y));
        else if(selected==("line"))
            g2.drawLine(start.x,start.y,end.x,end.y);
        }
        catch(Exception e)
        {}
        }
    //Function to draw the shape on image
    public void draw()
    {
      Graphics2D g2 = image.createGraphics();
      g2.setPaint(color);
      if(selected=="line")
            g2.drawLine(start.x, start.y, end.x, end.y);
      if(selected=="elipse")
            g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y));
      if(selected=="rect")
            g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y));
      repaint();
      g2.dispose();
      start=null;
    } 

    //To add the point to the board which is broadcasted by the server  
    public  synchronized void addPoint(Point ps,String varname,String shape,String event) 
    {
        try
        {
            if(end==null)
                end = new Point();
            if(start==null)
                start = new Point();
            if(shape.equals("elipse"))
                selected="elipse";
            else if(shape.equals("line"))
                selected="line";
            else if(shape.equals("rect"))
                selected="rect";
            else if(shape.equals("erase"))
            {
                selected="erase";
                erase();
            }
            if(end!=null && start!=null)
            {
                if(varname.equals("end"))
                        end=ps;
                if(varname.equals("mp"))
                        mp=ps;          
                if(varname.equals("start"))
                        start=ps;
                if(event.equals("drag"))
                       repaint();
                else if(event.equals("release"))
                        draw();
        }
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
} 
    //To set the size of the image
    public void setWidth(int x,int y)
    {
        System.out.println("("+x+","+y+")");
        w=x;
        h=y;
        image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
         Graphics2D g2 = image.createGraphics();
         g2.setPaint(Color.white);
         g2.fillRect(0,0,w,h);
         g2.dispose();
    }

    //Function which provides the erase functionality
    public void erase() 
    {
        Graphics2D pic=(Graphics2D) image.getGraphics();
        pic.setPaint(Color.white);
        pic.fillRect(start.x, start.y, 10, 10);
    }

    //Function to add buttons into the panel, calling this function returns a panel  
    public JPanel addButtons()
    {
        JPanel buttonpanel=new JPanel();
        JPanel row1=new JPanel();
        JPanel row2=new JPanel();
        JPanel row3=new JPanel();
        JPanel row4=new JPanel();
        buttonpanel.setPreferredSize(new Dimension(80,80));

        //buttonpanel.setMinimumSize(new Dimension(150,150));
        row1.setLayout(new BoxLayout(row1,BoxLayout.X_AXIS));
        row1.setPreferredSize(new Dimension(150,150));
        row2.setLayout(new BoxLayout(row2,BoxLayout.X_AXIS));
        row3.setLayout(new BoxLayout(row3,BoxLayout.X_AXIS));
        row4.setLayout(new BoxLayout(row4,BoxLayout.X_AXIS));
        buttonpanel.setLayout(new BoxLayout(buttonpanel,BoxLayout.Y_AXIS));

        elipse.addActionListener(this);
        rectangle.addActionListener(this);
        line.addActionListener( this);
        save.addActionListener( this);
        erase.addActionListener( this);

        buttonpanel.add(Box.createRigidArea(new Dimension(10,10)));
        row1.add(elipse);
        row1.add(Box.createRigidArea(new Dimension(5,0)));
        row1.add(rectangle);
        buttonpanel.add(row1);
        buttonpanel.add(Box.createRigidArea(new Dimension(10,10)));

        row2.add(line);
        row2.add(Box.createRigidArea(new Dimension(5,0)));
        row2.add(empty);
        buttonpanel.add(row2);
        buttonpanel.add(Box.createRigidArea(new Dimension(10,10)));

        row3.add(save);
        buttonpanel.add(row3);
        buttonpanel.add(Box.createRigidArea(new Dimension(10,10)));

        row4.add(erase);
        buttonpanel.add(row4);
        return buttonpanel;
    }
    //To save the image drawn
    public void save()
    {
        try 
        {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos);
            JFileChooser fc = new JFileChooser();
            fc.showSaveDialog(this);        
            encoder.encode(image);
            byte[] jpgData = bos.toByteArray();
            FileOutputStream fos = new FileOutputStream(fc.getSelectedFile()+".jpeg");
            fos.write(jpgData);
            fos.close();
        //add replce confirmation here

        } 
        catch (IOException e) 
        {           
            System.out.println(e);
        }
    }
    public void mouseClicked(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mouseEntered(MouseEvent arg0) {

    }
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    public void mousePressed(MouseEvent e) 
    {
            if(selected=="line"||selected=="erase")
            {
                start=e.getPoint();
                client.broadcast(start,"start", selected,"press");
            }
            else if(selected=="elipse"||selected=="rect")
            {
                mp = e.getPoint();
                client.broadcast(mp,"mp", selected,"press");
            }
    }
    public void mouseReleased(MouseEvent e) 
    {
        if(start!=null)
        {
            if(selected=="line")
            {
                end=e.getPoint();           
                client.broadcast(end,"end", selected,"release");
            }
            else if(selected=="elipse"||selected=="rect")
            {
                end.x = Math.max(mp.x,e.getX());
                end.y = Math.max(mp.y,e.getY());
                client.broadcast(end,"end", selected,"release");
            }
            draw();
        }
    //start=null;
    }
    public void mouseDragged(MouseEvent e) 
    {
        if(end==null)
            end = new Point();

        if(start==null)
                start = new Point();

         if(selected=="line")
         {
            end=e.getPoint();
            client.broadcast(end,"end", selected,"drag");
         }
        else if(selected=="erase")
        {
             start=e.getPoint();
             erase();
            client.broadcast(start,"start", selected,"drag");
        }
        else if(selected=="elipse"||selected=="rect")
        {
            start.x = Math.min(mp.x,e.getX());
            start.y = Math.min(mp.y,e.getY());
            end.x = Math.max(mp.x,e.getX());
            end.y = Math.max(mp.y,e.getY());
            client.broadcast(start,"start", selected,"drag");
            client.broadcast(end,"end", selected,"drag");
        }
        repaint();
    }
    @Override
    public void mouseMoved(MouseEvent arg0) {
        // TODO Auto-generated method stub

    } 
    public void actionPerformed(ActionEvent e) 
    {
        if(e.getSource()==elipse)
            selected="elipse";
        if(e.getSource()==line)
            selected="line";    
        if(e.getSource()==rectangle)
            selected="rect";
        if(e.getSource()==save)
            save();
        if(e.getSource()==erase)
        {
            selected="erase";
            erase();
        }
    }
} 

class Button extends JButton
{
    String name;
    public Button(String name) 
    {
        this.name=name; 
        Dimension buttonSize = new Dimension(35,35);
        setMaximumSize(buttonSize);     
    }
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        //g2.setStroke(new BasicStroke(1.2f));
        if (name == "line")     g.drawLine(5,5,30,30);   
        if (name == "elipse") g.drawOval(5,7,25,20);
        if (name== "rect") g.drawRect(5,5,25,23);

    }
}

Answer 1

Essayez de maintenir un panneau pour chaque utilisateur, et les couche sur le dessus de l'autre. Tant que les arrière-plans sont transparents, vous devriez les voir très bien.

Modifier Pour atteindre les couches, vous pouvez essayer JLayeredPane .

Answer 2

Je ne vois pas de code là que traite les demandes qui arrivent du client. En supposant que se passe sur un fil d'arrière-plan, assurez-vous d'utiliser SwingUtilities.invokeLater pour effectuer les modifications du EDT. Mise à jour de composants d'interface utilisateur de partout, mais l'EDT provoque un comportement imprévisible. Voir aussi Concurrency Swing

En outre, ce genre de chose ne va pas travailler:

    if (name == "line")     g.drawLine(5,5,30,30);   

En Java, l'opérateur effectue une comparaison == d'identité. Il évalue vrai si name et "line" sont le même objet. Il évaluera false si elles font référence à des objets différents, même si elles ont la même valeur. Pour comparer l'égalité, vous devez utiliser la méthode .equals().