Hello everyone,

I have three class
Server : QTcpServer
ServerThread : QThread

and main class (GUI)

Have a look at my code.
Qt Code: 
  1. #ifndef SERVER_H
  2. #define SERVER_H
  3.  
  4. #include <QTcpServer>
  5. #include <QByteArray>
  6.  
  7. class ServerThread;
  8. class Dialog;
  9.  
  10. class Server : public QTcpServer
  11. {
  12.     Q_OBJECT
  13. private:
  14.     Dialog *parent_;
  15. public:
  16.     explicit Server(Dialog *parent);
  17.     void incomingConnection(int socketDescriptor
  18.                             );
  19.     void startServer(int);
  20. signals:
  21.    void received(QString data);
  22. public slots:
  23.  void onreceived(QString data);
  24. };
  25.  
  26. #endif // SERVER_H
  27.  
  28. #ifndef SERVERTHREAD_H
  29. #define SERVERTHREAD_H
  30.  
  31. #include <QThread>
  32. #include <QByteArray>
  33. #include "dialog.h"
  34. class QTcpSocket;
  35.  
  36. class ServerThread : public QThread
  37. {
  38.     Q_OBJECT
  39. private:
  40.     int socketDescriptor_;
  41.  
  42.     Dialog *parent_;
  43. public:
  44.     explicit ServerThread(int socketDescriptor,Dialog *parent);
  45.     QTcpSocket *tcpSocket;
  46.     void run(void);
  47.     bool emit_signal;
  48. signals:
  49.     void received_sgl(QString str);
  50. public slots:
  51.     void received(void);
  52.     void disconnected(void);
  53.  
  54. };
  55.  
  56. #endif // SERVERTHREAD_H
  57.  
  58. #ifndef DIALOG_H
  59. #define DIALOG_H
  60.  
  61. #include <QDialog>
  62. #include <QString>
  63. #include <QByteArray>
  64. namespace Ui {
  65.     class Dialog;
  66. }
  67.  
  68. class QTcpSocket;
  69. class Server;
  70. class Dialog : public QDialog
  71. {
  72.     Q_OBJECT
  73.  
  74. public:
  75.     explicit Dialog(QWidget *parent = 0);
  76.     ~Dialog();
  77.     QTcpSocket *socket;
  78.      Server *s;
  79.  
  80.      void update(QString s);
  81.  
  82. private slots:
  83.     void on_pushButton_2_clicked();
  84.     void on_pushButton_clicked();
  85.     void received();
  86.     void rcd_(QByteArray arr);
  87.  
  88.  
  89. signals:
  90. private:
  91.     Ui::Dialog *ui;
  92. };
  93.  
  94. #endif // DIALOG_H
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and following implementation
Qt Code: 
  1. SERVER.cpp
  2.  
  3. #include "server.h"
  4. #include "serverthread.h"
  5. #include <QDebug>
  6. Server::Server(Dialog *parent) :
  7.     QTcpServer(parent),parent_(parent)
  8. {
  9. }
  10. void Server::startServer(int port)
  11. {
  12.  
  13.     this->listen(QHostAddress::Any,port);
  14.     qDebug()<<"listening!";
  15. }
  16.  
  17. void Server::incomingConnection(int socketDescriptor)
  18. {
  19.     qDebug()<<"Server::incomming connection";
  20.     ServerThread *thread=new ServerThread(socketDescriptor,parent_);
  21.     connect(thread,SIGNAL(received_sgl(QString)),this,SLOT(onreceived(QString)));
  22.     connect(thread,SIGNAL(finished()),thread,SLOT(deleteLater()));
  23.     thread->start();
  24.  
  25. }
  26.  
  27.  
  28. void Server::onreceived(QString data)
  29. {
  30.     qDebug()<<"updating...::::"<<QString(data);
  31.     parent_->update("updating..."+data);
  32.  
  33.  
  34. }
  35.  
  36. ServerThread.cpp
  37. #include "serverthread.h"
  38. #include <QTcpSocket>
  39. #include <QDebug>
  40.  
  41.  
  42.  
  43. ServerThread::ServerThread(int socketDescriptor,Dialog *parent) :
  44.     QThread(parent),socketDescriptor_(socketDescriptor),parent_(parent)
  45. {
  46.  
  47. }
  48.  
  49.  
  50.  
  51.  
  52. void ServerThread::run()
  53. {
  54.     tcpSocket=new QTcpSocket(parent_);
  55.        tcpSocket->setSocketDescriptor(socketDescriptor_);
  56.  
  57.        connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(received()),Qt::DirectConnection);
  58.        connect(tcpSocket,SIGNAL(disconnected()),this,SLOT(disconnected()),Qt::DirectConnection);
  59.  
  60.        qDebug()<<"ServerThread::run";
  61.  
  62.        exec();
  63. }
  64.  
  65.  
  66. void ServerThread::received()
  67. {
  68.  
  69.     qDebug()<<"ServerThread::received()"<<QString(tcpSocket->readAll());
  70.  
  71. emit received_sgl(QString(tcpSocket->readAll()));
  72.  
  73.     if (tcpSocket->isWritable())
  74.     {
  75.         tcpSocket->write(QByteArray("writing..."));
  76.  
  77.     }
  78. }
  79.  
  80. void ServerThread::disconnected()
  81. {
  82.     tcpSocket->deleteLater();   //delete tcpSocket once exit() for thread is executed
  83.     exit(); //exit the thread
  84. }
  85.  
  86. Dialog.cpp
  87.  
  88. #include "dialog.h"
  89. #include "ui_dialog.h"
  90. #include "server.h"
  91.  
  92. #include <QTcpSocket>
  93. #include <QDebug>
  94. Dialog::Dialog(QWidget *parent) :
  95.     QDialog(parent),
  96.     ui(new Ui::Dialog)
  97. {
  98.     ui->setupUi(this);
  99.  
  100.     s=new Server(this);
  101.     socket=new QTcpSocket(this);
  102.  
  103.     QObject::connect(socket, SIGNAL(readyRead()), this, SLOT(received()));
  104.     QObject::connect(s, SIGNAL(received(QByteArray)), this, SLOT(rcd_(QByteArray)));
  105.  
  106. }
  107.  
  108. Dialog::~Dialog()
  109. {
  110.     delete ui;
  111. }
  112. void Dialog::rcd_(QByteArray arr)
  113. {
  114.     ui->lblmsg->setText(QString(arr));
  115.     qDebug()<<QString(arr);
  116. }
  117.  
  118. void Dialog::on_pushButton_2_clicked()
  119. {
  120.  
  121.  
  122.     s->startServer(ui->lineEdit->text().toInt());
  123.     ui->lineEdit->setEnabled(false);
  124.  
  125. }
  126. void Dialog::received()
  127. {
  128.     qDebug()<<"received by client";
  129.  
  130.     update(QString(socket->readAll()));
  131.  
  132. }
  133.  
  134. void Dialog::on_pushButton_clicked()
  135. {
  136.     qDebug()<<"sending...";
  137.     socket->open(QAbstractSocket::ReadWrite);
  138.  
  139.     socket->connectToHost(ui->lineEdit_3->text(),ui->lineEdit_2->text().toInt());
  140.     socket->write("write now");
  141.  
  142.     socket->close();
  143.    // socket->close();
  144.     //delete socket;
  145.  
  146. }
  147.  
  148. void Dialog::update(QString s)
  149. {
  150.     ui->lblmsg->setText(s);
  151. }
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it works fine and emits signal and is caught my slot. But by the time slot catches the signal "data" is already lost

could someone spot out problem?

(if i need to emit signal in run() i have tried to do it using boolean flag but didn't quite work)


Thank you so much for your time