QT网络通信 UDP广播+多线程问题 - QTCN开发网

suzhuorui

2019-08-22 09:56

问题解决了，上完整的代码

发送端界面cpp

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#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QUdpSocket>
#include "udpsend.h"
#include <QMutex>

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

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

int num=0;
QMutex mutex;

void MainWindow::on_pushButton_clicked()
{
      UdpSend *thread[5];
      for(int i=0;i<5;i++)
      {
            mutex.lock();
            qDebug()<<i;
            thread[i]=new UdpSend();
            connect(thread[i],SIGNAL(finished()),this,SLOT(deleteLater()));
            thread[i]->start();
      }
}

发送端线程cpp
UdpSend线程类

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[color=#000000]#include "udpsend.h"[/color]
[color=#000000]#include <QMutex>[/color]
[color=#000000]UdpSend::UdpSend(QObject *parent) : QThread(parent)[/color]
[color=#000000]{[/color]

[color=#000000]}[/color]

[color=#000000]extern int num;[/color]
[color=#000000]extern QMutex mutex;[/color]

[color=#000000]void UdpSend::run()[/color]
[color=#000000]{[/color]
[color=#000000]    myUdpSocket=new QUdpSocket(this);[/color]
[color=#000000]    QString data="广播"+QString::number(num);[/color]
[color=#000000]    num++;[/color]
[color=#000000]    myUdpSocket->writeDatagram(data.toUtf8(),QHostAddress::Broadcast,quint16(5555));[/color]
[color=#000000]    mutex.unlock();[/color]
[color=#000000]    exec();[/color]
[color=#000000]}[/color]

接收端cpp

复制代码

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
      ui->setupUi(this);
      udpsocket=new QUdpSocket(this);
      udpsocket->bind(QHostAddress::AnyIPv4,quint16(5555));
      connect(udpsocket,SIGNAL(readyRead()),this,SLOT(ricv_msg()));
}

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

void MainWindow::ricv_msg()
{
      QHostAddress sendID;
      quint16 sendport;
      QByteArray data;
      if(udpsocket->hasPendingDatagrams())
      {
            data.resize(udpsocket->pendingDatagramSize());
            udpsocket->readDatagram(data.data(),data.size(),&sendID,&sendport);
      }
      QString str="发送端的IP："+sendID.toString()+"  端口号："+QString::number(sendport)+"  内容："+data;
      ui->textBrowser->append(str);
}

总结一下
1.首先使用循环创建多线程时需要加锁
2.在接收端的接收函数不要使用while(udpsocket->hasPendingDatagrams()),而要用if(udpsocket->hasPendingDatagrams())
3.接收数据的大小不能用data.resize(udpsocket->bytesAvailable());，而要用data.resize(udpsocket->pendingDatagramSize());，否则可能会有接收大小不一致，会导致出现意外乱码

以上代码为我个人意见，若有问题请指出来共同进步