如何在 QThread 和 QGui 之间传递参数？

Question

我在 QtGui 应用程序上工作，在后台进行套接字编程我想从 gui 中的行编辑中获取 IP 地址和端口并将其传递给 QThread 线程正常工作，但我无法传递我尝试使用构造函数的参数，但它停止了所有项目。

我想在启动 QThread 之前将参数从 Gui 传递给 class 中的构造函数或自定义函数。

我还需要绘制从套接字接收到的数据。所以解决这个问题的任何方法我尝试将对象指针传递给 class 但出现了很多错误

这里是线程代码和ui代码

//client code
#include "clientclass.h"
#include <QThread>
#include <QDebug>

clientClass::clientClass(char *serverIp, unsigned int serverPort, char *idname ="SCR")
{
    this->ip=serverIp;
    this->port=serverPort;
    this->id=idname;


    std::cout<<ip<<port<<id<<std::endl;

};

int clientClass::connection()
{

    SOCKET socketDescriptor;
    int numRead;

    char id[20]="SCR";

    unsigned int maxEpisodes;
    unsigned int maxSteps;
    char trackName[1000];
    BaseDriver::tstage stage;

    tDriver drive;
    strcpy(drive.trackName,trackName);
    drive.stage = stage;


    tSockAddrIn serv_addr;
    struct timeval timeVal;
    fd_set readSet;
    char buf[UDP_MSGLEN];

    // Create a socket (UDP on IPv4 protocol)
    socketDescriptor = socket(AF_INET, SOCK_DGRAM, 0);
    if (INVALID(socketDescriptor))
    {
        response = "Error: cannot create socket";
        return (1);
    }

    // Set some fields in the serverAddress structure.

    serv_addr.sin_family=AF_INET;
    serv_addr.sin_port=htons((this->port));
    serv_addr.sin_addr.s_addr = inet_addr(this->ip);
    //std::cout<<serv_addr.sin_port<<std::endl;
    std::cout<<serv_addr.sin_addr.s_addr<<std::endl;

    bool shutdownClient=false;
    unsigned long curEpisode=0;
    do
    {

        do
        {
            // Initialize the angles of rangefinders
            float angles[19];
            drive.init(angles);
            string initString = SimpleParser::stringify(string("init"),angles,19);
            response =QString ("Sending id to server: %1").arg(id);
            initString.insert(0,id);
            response =QString("Sending init string to the server");
            if (sendto(socketDescriptor, initString.c_str(), initString.length(), 0,
                       (struct sockaddr *) &serv_addr,
                       sizeof(serv_addr)) < 0)
            {

                response ="Error: cannot send data ";
                CLOSE(socketDescriptor);
                return (1);
            }

            // wait until answer comes back, for up to UDP_CLIENT_TIMEUOT micro sec
            FD_ZERO(&readSet);
            FD_SET(socketDescriptor, &readSet);
            timeVal.tv_sec = 0;
            timeVal.tv_usec = UDP_CLIENT_TIMEUOT;

            if (select(socketDescriptor+1, &readSet, NULL, NULL, &timeVal))
            {
                // Read data sent by the solorace server
                memset(buf, 0x0, UDP_MSGLEN);  // Zero out the buffer.
                numRead = recv(socketDescriptor, buf, UDP_MSGLEN, 0);
                if (numRead < 0)
                {
                    response ="Error: didn't get response from server";
                }
        else
        {
                    response = "Received";

                    if (strcmp(buf,"***identified***")==0)
                            break;
                }
          }

        }  while(1);

    unsigned long currentStep=0;

        while(1)
        {
            // wait until answer comes back, for up to UDP_CLIENT_TIMEUOT micro sec
            FD_ZERO(&readSet);
            FD_SET(socketDescriptor, &readSet);
            timeVal.tv_sec = 0;
            timeVal.tv_usec = UDP_CLIENT_TIMEUOT;



            cout<<"in connection"<<endl;



            if (select(socketDescriptor+1, &readSet, NULL, NULL, &timeVal))
            {
                // Read data sent by the solorace server
                memset(buf, 0x0, UDP_MSGLEN);  // Zero out the buffer.
                numRead = recv(socketDescriptor, buf, UDP_MSGLEN, 0);

                if (numRead < 0)
                {
                    response = "Error : didn't get response from server";
                    CLOSE(socketDescriptor);
                    return (1);
                }

                if (strcmp(buf,"***shutdown***")==0)
                {
                    drive.onShutdown();
                    shutdownClient = true;
                    response="Client Shutdown";
                    break;
                }

                if (strcmp(buf,"***restart***")==0)
                {
                    drive.onRestart();
                    response ="Client Restart";
                    break;
                }
                /**************************************************
                 * Compute The Action to send to the solorace sever
                 **************************************************/

        if ( (++currentStep) != maxSteps)
        {
                    string action = drive.drive(string(buf));
                    memset(buf, 0x0, UDP_MSGLEN);
                    sprintf(buf,"%s",action.c_str());

        }
        else
            sprintf (buf, "(meta 1)");

                if (sendto(socketDescriptor, buf, strlen(buf)+1, 0,
                           (struct sockaddr *) &serv_addr,
                           sizeof(serv_addr)) < 0)
                {
                    response = "Error : cannot send data ";
                    CLOSE(socketDescriptor);
                    return (1);
                }
            }
            else
            {
                response ="Server did not respond in 1 second ";
            }
        }
    } while(shutdownClient==false && ( (++curEpisode) != maxEpisodes) );

    if (shutdownClient==false)
    drive.onShutdown();
    CLOSE(socketDescriptor);
    return 0;
}

>

// ui code 
<
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QString>
#include <time.h>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    thread =new QThread();
    QString response;

    mine = new clientClass("127",3001,"SCR");

    mine->moveToThread(thread);


    connect(thread, SIGNAL(started()),mine, SLOT(connection()));

}

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

void MainWindow::on_pushButton_clicked()
{
    thread->start();

    if(thread->isRunning()) std::cout<< "is running"<<endl;


}

Answer 1

创建一个新的 class Worker Subclassing QObject 并使用 signals/slots 在您的工作人员和 UI 之间进行通信。

在我看来，每次您想运行流程时都创建一个新的 worker 比重用同一个 worker 更容易。因此，您必须在创建新工作人员之前删除该工作人员。您可以为此使用 QObject::deleteLater 插槽。

当您必须将结果发送到 UI 时，您需要在 Worker class 中触发一个信号，并且在 MainWindow 中需要一个插槽来处理结果。

您还需要一个标志来停止 worker 并打破无限循环。

一个工人的例子：

class MyWorker: public QObject
{
    Q_OBJECT
public:
    MyWorker(QString const& aAddress, unsigned int aPort, QObject* parent=nullptr): QObject(parent),
        address(aAddress), port(aPort)
    {}
    virtual ~MyWorker()
    {
        qDebug() << "Deleted" << address << port;
    }
public slots:
    void run()
    {
        running = true;
        int count = 0;
        while(running)
        {
            QCoreApplication::processEvents();
            for (int i = 0; i != 100000; ++i) { // Long time processing
            for (int i = 0; i != 100; ++i) {}
            }
            ++count;
            resultAvailable(QString("Loop count %1").arg(count));
        }
        finished(); // Inform that the worker has finished its task
    }

    void stop() // Call it to stop the thread
    {
        qDebug() << QThread::currentThreadId();
        running = false;
    }
signals:
    void resultAvailable(QString const&); // Will send message to the UI
    void finished();
private:
    QString address;
    unsigned int port;
    bool running;
};

一个 UI 调用工作器并显示从它收到的结果。

class MyWindow: public QWidget
{
    Q_OBJECT
public:
    MyWindow(QWidget* parent=nullptr): QWidget(parent),
    address(new QLineEdit),
    port(new QLineEdit),
    ok(new QPushButton("Run")),
    label(new QLabel())
    {

        QVBoxLayout* layout = new QVBoxLayout(this);
        layout->addWidget(address);
        layout->addWidget(port);
        layout->addWidget(ok);
        layout->addWidget(label);
        connect(ok, &QPushButton::clicked, this, &MyWindow::process);
    }
public slots:
    void process()
    {
        // Create a new worker and its thread
        QThread* workerThread = new QThread(this);
        MyWorker* worker = new MyWorker(address->text(), port->text().toUInt());
        worker->moveToThread(workerThread); // Put the worker in a dedicated thread

        connect(ok, &QPushButton::clicked, worker, &MyWorker::stop); // If user clicks on the ok btn again, delete the previous worker
        connect(worker, &MyWorker::resultAvailable, this, &MyWindow::processResult); // Process the data sent by the worker in the UI
        connect(worker, &MyWorker::finished, workerThread, &QThread::quit); // Stop the thread when the worker has finished
        connect(workerThread, &QThread::finished, workerThread, &MyWorker::deleteLater); // Delete the thread when finished
        connect(workerThread, &QThread::finished, worker, &MyWorker::deleteLater); // Delete the thread when finished
        connect(workerThread, &QThread::started, worker, &MyWorker::run); // Starts the worker when the thread is launched
        workerThread->start(); // The worker will be called
    }

    void processResult(QString const& result)
    {
        label->setText("The result: " + result);
    }
private:
    QLineEdit* address;
    QLineEdit* port;
    QPushButton* ok;
    QLabel* label;
};

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