QT Udp socket

Tibet

QObject::connect: No such signal QUdpSocket::Read

I get an error.

MainWindow.h looks like this...........................................

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QUdpSocket>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
void Hello1();

signals:

public slots:

void Hello2();
void Read1();

private slots:
void on_pushButton_clicked();

private:
Ui::MainWindow *ui;
QUdpSocket *socket;

};
#endif // MAINWINDOW_H

MainWindow.cpp look like this.............................................

#include "MainWindow.h"
#include "ui_MainWindow.h"
#include <QDebug>
#include <QTimer>
#include <QLabel>
#include<iostream>

QTimer *timer = new QTimer();
static QUdpSocket *socket;

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);

socket = new QUdpSocket(this);
socket->bind(QHostAddress::LocalHost, 1234);
connect(socket, SIGNAL(Read1()), this, SLOT(Read1()));


timer = new QTimer(this);
connect(timer, SIGNAL(timeout()),this,SLOT(Hello2()));
timer -> start(1000);

// connect(timer, SIGNAL(timeout()),this,SLOT(Hello1()));
// timer -> start(1000);

ui -> pushButton -> setCheckable(true);

}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::Hello2()
{
qDebug() << "update..";
}

void MainWindow::Hello1()
{

QByteArray Data;
Data.append("Hello from UDP land");

// char Name[1000];
// std::cout << "Your message : ";
// std::cin >> Name;
// qDebug() << "Hello " << Name << "\n";

socket->writeDatagram(Data, QHostAddress::LocalHost, 1234);

}

void MainWindow::Read1()
{
QByteArray buffer;
buffer.resize(socket->pendingDatagramSize()); //bekleyen data miktarı

QHostAddress sender;
quint16 senderPort;

if ( socket->readDatagram(buffer.data(), buffer.size(),&sender,&senderPort) != -1)
{

qDebug() << "Message from: " << sender.toString();
qDebug() << "Message port: " << senderPort;
qDebug() << "Message: " << buffer;

} else {
;// handle error
}
}

void MainWindow::on_pushButton_clicked()
{

ui ->label->setText("1");

}

and main.cpp look like .......................

#include "MainWindow.h"
#include "MyUDP.h"

#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);

MainWindow client;

client.Hello1();

MainWindow w;
w.show();
return a.exec();

}

Christian Ehrlicher

@Tibet said in QT Udp socket:

QObject::connect: No such signal QUdpSocket::Read

And that's correct - QUdpSocket has no such signal.

/edit: and please fix your post to use the code tags to make the code more readable!

JonB

@Tibet

QObject::connect: No such signal QUdpSocket::Read

Not only as @Christian-Ehrlicher says, but in addition tell us clearly which line you get this error on, and what the code of the line is? Because I don't see any call at all to QUdpSocket::Read anywhere in the code you show, so I don't even see how you could get that error message; if I didn't know better, I'd say you either have not copied & pasted the error message, or your code is not as shown....

Tibet

14:15:32: Starting /home/tibet/build-qtDeneme12-Desktop-Debug/qtDeneme12 ...
QObject::connect: No such signal QUdpSocket::Read1() in ../qtDeneme12/MainWindow.cpp:19
QObject::connect: (receiver name: 'MainWindow')
QObject::connect: No such signal QUdpSocket::Read1() in ../qtDeneme12/MainWindow.cpp:19
QObject::connect: (receiver name: 'MainWindow')

Christian Ehrlicher

@Tibet Again: there is no such signal in QUdpSocket!

JonB

@Tibet
So, as suspected, what you said was the error message never was the error message.... Please, if you post questions take the time to copy & paste the correct code and the correct error message, else people waste time trying to help you.

And again additional to @Christian-Ehrlicher .

I'm sorry, but if you have not already done so you really need to read Signals & Slots and have a proper understanding before you will get anywhere in Qt. Just trying things won't help you.

Also I strongly advise that you change over to the New Signal Slot Syntax before you go further. It will hep you by generating compiler messages when you have done something wrong.

Tibet

I'm very new at Qt. I guess the error might be about signal and slot. because ---- connect (socket, SIGNAL (Read1 ()), this, SLOT (Read1 ())); --- this part doesn't work. I don't know exactly about MyUDP.h

Christian Ehrlicher

@Tibet said in QT Udp socket:

connect (socket, SIGNAL (Read1 ()), this, SLOT (Read1 ())); --- this part doesn't work

And again: we know that it does not work because QUdpSocket has no such signal (said already two times before but you're ignoring it). The documentation has a working code snippet so why don't you follow them?

JonB

@Tibet

connect (socket, SIGNAL (Read1 ()), this, SLOT (Read1 ()));

Yes, it does not work. Because socket is a QUdpSocket, and as per that documentation page there is no such signal (or any method) as QUdpSocket::Read1. There is a signal QUdpSocket::readRead, and there is a method QUdpSocket::readDatagram() which you might want to call in a slot on that signal....

Tibet

@JonB thank u. I get it now <3. I used readyRead() and it was fixed.

Pablo J. Rogina

@Tibet said in QT Udp socket:

it was fixed.

so if your issue is solved now, please don't forget to mark your post as such!