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Lorsque je lance ce code, la méthode paintComponent n'est pas appelée Il peut s'agir d'une erreur très simple mais je ne sais pas pourquoi cela, plz.La méthode de peinture JPanel n'est pas appelée, pourquoi?
package test;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.image.BufferedImage;
import javax.swing.BorderFactory;
import javax.swing.JPanel;
class Userboard extends JPanel
{
static BufferedImage image;
String shape;
Point start;
Point end;
Point mp;
String selected;
int ex,ey;//eraser
int w,h;
public Userboard()
{
setOpaque(false);
System.out.println("paper");
setBackground(Color.white);
setBorder(BorderFactory.createLineBorder(Color.black));
}
public void paintComponent(Graphics g)
{
System.out.println("userboard-paint");
try
{
//g.drawImage(image, 0, 0, this);
Graphics2D g2 = (Graphics2D)g;
g2.setPaint(Color.black);
if(start!=null && end!=null)
{
if(selected==("elipse"))
{
System.out.println("userboard-elipse");
g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y));
System.out.println("userboard-elipse drawn");
}
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()
{
System.out.println("Userboard-draw");
System.out.println(selected);
System.out.println(start);
System.out.println(end);
Graphics2D g2 = image.createGraphics();
g2.setPaint(Color.black);
if(start!=null && end!=null)
{
if(selected=="line")
g2.drawLine(start.x, start.y, end.x, end.y);
else if(selected=="elipse")
{
System.out.println("userboard-elipse");
g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y));
System.out.println("userboard-elipse drawn");
}
else if(selected=="rect")
g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y));
}
start=null;
repaint();
g2.dispose();
}
//To add the point to the board which is broadcasted by the server
public 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"))
this.selected="elipse";
else if(shape.equals("line"))
this.selected="line";
else if(shape.equals("rect"))
this.selected="rect";
else if(shape.equals("erase"))
erase();
if(end!=null && start!=null)
{
if(varname.equals("end"))
end=ps;
else if(varname.equals("mp"))
mp=ps;
else if(varname.equals("start"))
start=ps;
if(event.equals("drag"))
repaint();
else if(event.equals("release"))
draw();
}
repaint();
}
catch(Exception e)
{
e.printStackTrace();
}
}
//Function which provides the erase functionality
public void erase()
{
Graphics2D pic=(Graphics2D) image.getGraphics();
pic.setPaint(Color.white);
if(start!=null)
pic.fillRect(start.x, start.y, 10, 10);
}
//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_ARGB);
}
//Function to add buttons into the panel, calling this function returns a panel
}
Code
qui instancier la classe userboard
public class Client extends Thread
{
Point point;
Paper paper;
Userboard userboard;
DatagramSocket datasocket=null;
public Client(DatagramSocket datasocket)
{
this.datasocket=datasocket;
}
//This function is to create the JFrame
public void createFrame()
{
JLayeredPane layerpane=new JLayeredPane();
JFrame frame=new JFrame("Whiteboard");
paper= new Paper(datasocket);
userboard=new Userboard();
frame.setLayout(new BorderLayout());
layerpane.setLayout(new BorderLayout());
layerpane.add(paper,BorderLayout.CENTER);
layerpane.add(userboard,BorderLayout.CENTER);//Panel where remote user draws
frame.add(paper.addButtons(),BorderLayout.WEST);
frame.add(layerpane,BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(640, 480);
frame.addWindowListener(new WindowAdapter()
{
public void windowOpened(WindowEvent e) {}
public void windowClosing(WindowEvent e)
{
Draw draw=new Draw();
draw. close();
}
});
paper.setWidth(frame.getWidth(),frame.getHeight());
userboard.setWidth(frame.getWidth(),frame.getHeight());
frame.setVisible(true);
}
/*
* This function is overridden from the thread class
* This function listens for incoming packets from the server
* which contains the points drawn by the other client
*/
public void run()
{
while (true)
{
try
{
byte[] buffer = new byte[512];
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
datasocket.receive(packet);
InputStream in=new ByteArrayInputStream(packet.getData(), packet.getOffset(),packet.getLength());
DataInputStream din=new DataInputStream(in);
int x=din.readInt();
int y=din.readInt();
String varname=din.readLine();
String var[]=varname.split("-",3);
point=new Point(x,y);
userboard.addPoint(point, var[0], var[1],var[2]);
}
catch (IOException ex)
{
ex.printStackTrace();
}
}
}
//This function is to broadcast the newly drawn point to the server
public void broadcast (Point p,String varname,String shape,String event)
{
try
{
ByteArrayOutputStream baos=new ByteArrayOutputStream();
DataOutputStream dos=new DataOutputStream(baos);
dos.writeInt(p.x);
dos.writeInt(p.y);
dos.writeBytes(varname);
dos.writeBytes("-");
dos.writeBytes(shape);
dos.writeBytes("-");
dos.writeBytes(event);
dos.close();
byte[]data=baos.toByteArray();
InetAddress ip=InetAddress.getByName("10.123.97.125");
DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8002);
datasocket.send(packet);
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
La signature de la méthode semble correcte. Pouvez-vous publier le code où vous instanciez UserBoard et l'ajouter à une fenêtre de niveau supérieur? – Adamski
Je viens d'exécuter votre code (en commentant certaines des classes non fournies) et la méthode de peinture de l'utilisateur a été appelée. Je pense que vous devez commencer à simplifier systématiquement votre code jusqu'à ce qu'il fonctionne pour vous, puis ajouter les choses une à la fois jusqu'à ce que vous voyiez où cela ne va pas. – Ash