问题描述
我刚刚开始为我的 Qt 应用程序实现 UDP 客户端。我跟着this example。我能够向远程主机发送数据和从远程主机接收数据。这已经在我的远程主机以及我正在为其开发此应用程序的本地客户端进行了验证(通过从我的 main.cpp 调用 handleReadyRead() 进行本地验证)。我似乎无法让 QUdpSocket 发出其 readyRead 信号。这是为什么?
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QTimer>
#include "udpclient.h"
static double value = 0;
static bool flash = true;
static UDPClient client;
int update1000()
{
QByteArray Data;
Data.append((char) 0x00);
Data.append((char) 0x2c);
Data.append((char) 0x1a);
Data.append((char) 0x2c);
Data.append((char) 0x92);
Data.append((char) 0xe6);
Data.append((char) 0xf6);
Data.append((char) 0xa0);
client.SendPacket(Data);
return 0;
}
int packetReady()
{
qInfo() << "packetReady";
return 0;
}
int main(int argc,char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc,argv);
qmlRegisterType<HorizontalBargraph>("com.kubie.horizontalBargraph",1,"HorizontalBargraph");
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
if (engine.rootObjects().isEmpty())
return -1;
QObject *object = engine.rootObjects()[0];
//qInfo() << "Initializing timer.";
QTimer timer1000;
QObject::connect(&timer1000,&QTimer::timeout,update1000);
timer1000.start(1000);
return app.exec();
}
udpclient.h
#ifndef UDPCLIENT_H
#define UDPCLIENT_H
#include <QUdpSocket>
class UDPClient : public QObject
{
Q_OBJECT
public:
explicit UDPClient(QObject *parent = nullptr);
void SendPacket(const QByteArray &buffer);
private:
QUdpSocket *socket = nullptr;
signals:
public slots:
void handleReadyRead();
};
#endif // UDPCLIENT_H
udpclient.cpp
#include "udpclient.h"
UDPClient::UDPClient(QObject *parent) :
QObject(parent)
{
socket = new QUdpSocket(this);
//We need to bind the UDP socket to an address and a port
//socket->bind(QHostAddress::LocalHost,1234); //ex. Address localhost,port 1234
socket->bind(QHostAddress::AnyIPv4,6969); //ex. Address localhost,port 1234
//connect(socket,SIGNAL(readyRead()),this,SLOT(handleReadyRead()));
connect(socket,&QUdpSocket::readyRead,&UDPClient::handleReadyRead);
}
void UDPClient::SendPacket(const QByteArray &buffer)
{
socket->writeDatagram(buffer,QHostAddress("192.168.174.10"),6969);
}
void UDPClient::handleReadyRead() //Read something
{
qInfo() << socket->hasPendingDatagrams();
QByteArray Buffer;
Buffer.resize(socket->pendingDatagramSize());
QHostAddress sender;
quint16 senderPort;
socket->readDatagram(Buffer.data(),Buffer.size(),&sender,&senderPort);
qInfo() << Buffer;
//The address will be sender.toString()
}
解决方法
一个 QML 应用程序需要(至少)一个 QGuiApplication 来运行。您将在命令行或 IDE 调试应用程序输出窗口中获得与此相关的调试输出。要针对此类问题获得更致命的警告,您可以设置环境变量 QT_FATAL_WARNINGS
(有关详细信息,请参阅 QDebug documentation)