Qt: QObject::connect: No such slot QObject::processPendingDatagrams() [duplicate] - qt

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When should Q_OBJECT be used?
(4 answers)
QT "No such slot" Error [duplicate]
(1 answer)
Closed 6 years ago.
I have written an UDP programme with Qt, and when I connect this:
connect(socket,SIGNAL(readyRead()),this,SLOT(processPendingDatagrams()));
the complier tells me that
no such slot
the error click here
and I want to know how to fix it, thank you!
P.S.
Here are my files:
files
Here are my codes:
enter code here
udptest.cpp:
#include "udptest.h"
#include <QObject>
#include <QUdpSocket>
#include <QtNetwork>
UDPtest::UDPtest()
{
socket = new QUdpSocket();
port = 2016;
socket->bind(port,QUdpSocket::ShareAddress
| QUdpSocket::ReuseAddressHint);
connect(socket,SIGNAL(readyRead()),this,SLOT(processPendingDatagrams()));
}
QString UDPtest::getIP()
{
QList<QHostAddress> list = QNetworkInterface::allAddresses();
foreach (QHostAddress address, list)
{
if(address.protocol() == QAbstractSocket::IPv4Protocol)
return address.toString();
}
return 0;
}
void UDPtest::sendMessage(QString message)
{
QByteArray data;
QDataStream out(&data,QIODevice::WriteOnly);
QString localHostName = QHostInfo::localHostName();
QString address = getIP();
out <<"123"<< localHostName << address << message;
socket->writeDatagram(data,data.length(),QHostAddress::Broadcast, port);
}
void UDPtest::processPendingDatagrams()
{qDebug()<<"receive";
while(socket->hasPendingDatagrams())
{
QByteArray datagram;
datagram.resize(socket->pendingDatagramSize());
socket->readDatagram(datagram.data(),datagram.size());
QDataStream in(&datagram,QIODevice::ReadOnly);
QString userName,localHostName,ipAddress,message;
QString time = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");
in >>userName >>localHostName >>ipAddress >>message;
QString msg=time+userName+localHostName+ipAddress+message;
msger=msg;
qDebug()<<msg;
}
}
QString UDPtest:: messager()
{
return msger;
}
main.cpp:
#include"udptest.h"
#include<QDebug>
#include <QtCore/QCoreApplication>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
qDebug()<<"123";
UDPtest test;
test.sendMessage("aha");
return a.exec();
}
udptest.h:
#ifndef UDPTEST_H
#define UDPTEST_H
#include <QObject>
#include <QUdpSocket>
#include <QtCore/QCoreApplication>
#include <QtNetwork>
class UDPtest:public QObject
{
public:
UDPtest();
QString messager();
void sendMessage(QString);
private slots:
void processPendingDatagrams();
private:
QString msger;
QUdpSocket *socket;
qint16 port;
QString getIP();
};
#endif // UDPTEST_H
QudptestConsole.pro:
QT += core
QT -= gui
QT += network
CONFIG += c++11
TARGET = QudptestConsole
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp \
udptest.cpp
HEADERS += \
udptest.h

Answer 1

You have forgotten Q_OBJECT macro in UDPtest class
class UDPtest: public QObject
{
Q_OBJECT
public:
UDPtest();
.....
}