clean solution?

[Dumbledore]

For a chat program, when I receive some text from a peer, how do I display this in my QTextBrowser?

I know about QTextBrowser::append(), but what I mean is: how do I get my socket instance to know about my QTextBrowser instance?

I could pass the pointer to QTextBrowser to QServer's constructor then to QSocket's constructor so that in my receiveText() slot I can use QTextBrowser::append() to output the text I receive... but is there a cleaner solution?

[wysota]

You can subclass a socket and make it emit a signal with the message you want to append to the browser. Then you can connect the socket and the browser from within a component which knows them both.

[Dumbledore]

I see what you are saying, and I have already subclassed tcpSocket, but I don't see an easy way to connect the signal to the appropriate slot.

The code is really simple, its just split into many files.

MSocket.cpp

#include "MSocket.h"
 
void MSocket::recv() {
  QTextStream in(this);
  QString inChat; 
  inChat = in.readLine();
  //chatOutput->append(inChat);  <- this can't work.
}

#include "MSocket.h"

void MSocket::recv() {
  QTextStream in(this);
  QString inChat; 
  inChat = in.readLine();
  //chatOutput->append(inChat);  <- this can't work.
}

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MServer.cpp

#include "MServer.h"
 
MServer::MServer(QObject* parent) : QTcpServer(parent) {
}	
 
void MServer::incomingConnection(int socketDescriptor) {
  MSocket* socket = new MSocket(this);
  socket->setSocketDescriptor(socketDescriptor);
}

#include "MServer.h"

MServer::MServer(QObject* parent) : QTcpServer(parent) {
}	

void MServer::incomingConnection(int socketDescriptor) {
  MSocket* socket = new MSocket(this);
  socket->setSocketDescriptor(socketDescriptor);
}

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MChat.cpp

#include "MChat.h"
#include <QMessageBox>
 
 
MChat::MChat(QMainWindow *parent) : QMainWindow(parent), tcpServer(NULL) {
  setupUi(this);
 
  //connections
  connect(inputChat, SIGNAL(pressedReturn()),
                sendButton, SLOT(animateClick()));
 
}
 
void MChat::on_actionConnect_activated() {
  if (NULL == tcpServer) {
    tcpServer = new MServer(this);
    connect(tcpServer, SIGNAL(inText(QString&)), this,  
                  SLOT(outputText(QString&)));
    if (!tcpServer->listen(QHostAddress::Any, 43545)) {
      QMessageBox::critical(this, tr("MChat"),
			    tr("Unable to start the server: %1.")
			    .arg(tcpServer->errorString()));
      close();
      return;
    }  
 
  }
}
 
}

#include "MChat.h"
#include <QMessageBox>


MChat::MChat(QMainWindow *parent) : QMainWindow(parent), tcpServer(NULL) {
  setupUi(this);

  //connections
  connect(inputChat, SIGNAL(pressedReturn()),
                sendButton, SLOT(animateClick()));

}

void MChat::on_actionConnect_activated() {
  if (NULL == tcpServer) {
    tcpServer = new MServer(this);
    connect(tcpServer, SIGNAL(inText(QString&)), this,  
                  SLOT(outputText(QString&)));
    if (!tcpServer->listen(QHostAddress::Any, 43545)) {
      QMessageBox::critical(this, tr("MChat"),
			    tr("Unable to start the server: %1.")
			    .arg(tcpServer->errorString()));
      close();
      return;
    }  

  }
}

}

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[Dumbledore]

So my solution is to first emit a signal with MSocket:

emit incomingChat(text);

emit incomingChat(text);

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Catch it with a slot from MServer, and emit it again to MChat:

slot relayText(text) { 
   emit text(text); 
}

slot relayText(text) { 
   emit text(text); 
}

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Catch it in MChat with a slot:

MChat:: outputText(QString& text) {
   chatOutput->append(text); 
}

MChat:: outputText(QString& text) {
   chatOutput->append(text); 
}

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There must be a cleaner way though.

[jacek]

You can connect a signal to a signal.

[Dumbledore]

alright, that makes it a little nicer.