如何双向通信 Qt 应用程序

Question

我想在我的 Qt 应用程序之间创建双向通信。我想使用 QProcess 来做到这一点。我从根应用程序成功调用子应用程序并发送测试数据而没有任何错误，但我无法在子应用程序中接收任何数据。我将不胜感激任何帮助。我正在使用 Qt 4.7.1。在我的测试代码下面：

根应用：

InterProcess::InterProcess(QObject *parent) : QProcess(parent)
{
    process = new QProcess(this);
    process->start(myChildApp);
    process->waitForStarted();
    process->setCurrentWriteChannel(QProcess::StandardOutput);
    process->write("Test");

    connect( process, SIGNAL(error(QProcess::ProcessError)), this, SLOT(error(QProcess::ProcessError)) );
    connect( process, SIGNAL(readyReadStandardError()), this, SLOT(readyReadStandardError()) );
    connect( process, SIGNAL(readyReadStandardOutput()), this, SLOT(readyReadStandardOutput()) );     

QByteArray InterProcess::read()
{
    QByteArray readBuffer = process->readAllStandardOutput();
    return readBuffer;
}

void InterProcess::error( QProcess::ProcessError error )
{
    qDebug() << "Error!";
    qDebug() << error;
}

void InterProcess::readyReadStandardError()
{
    qDebug() << "Ready to read error.";
    qDebug() << process->readAllStandardError();
}

void InterProcess::readyReadStandardOutput()
{
    qDebug() << "The output:";
    QByteArray readBuffer = process->readAllStandardOutput();
    qDebug() << readBuffer;
}

子应用：

InterProcess::InterProcess(QObject *parent) : QProcess(parent)
{
    process = new QProcess();
    process->setCurrentReadChannel(QProcess::StandardOutput);

    connect( process, SIGNAL(readyRead()), this, SLOT(readyReadStandardOutput()));
    connect( process, SIGNAL(error(QProcess::ProcessError)), this, SLOT(error(QProcess::ProcessError)) );
    connect( process, SIGNAL(readyReadStandardError()), this, SLOT(readyReadStandardError()) );
    connect( process, SIGNAL(readyReadStandardOutput()), this, SLOT(readyReadStandardOutput()) );

    process->waitForReadyRead(5000);
}

void InterProcess::readyReadStandardError()
{
    qDebug() << "Ready to read error.";
    qDebug() << process->readAllStandardError();
    setText("REady error");
}

void InterProcess::readyReadStandardOutput()
{
    setMessage("2");
    qDebug() << "The output:";
    QByteArray readBuffer = process->readAllStandardOutput();
    qDebug() << readBuffer;
}
void InterProcess::error( QProcess::ProcessError error )
{
    qDebug() << "Error!";
    qDebug() << error;
    setText(QString(error));
}

Answer 1

很难在一个答案中解释所有错误，因此只需查看代码并询问您是否仍有问题。 这是使用 QProcess 作为 IPC 的示例。

这是你的主要进程，它创建额外的进程并连接到它的信号

MyApplicaiton.h

#ifndef MYAPPLICATION_H
#define MYAPPLICATION_H
#include <QApplication>

class InterProcess;
class MyApplication : public QApplication {
    Q_OBJECT
public:
    MyApplication(int &argc, char **argv);
signals:
    void mainApplicationSignal();
private slots:
    void onInterProcessSignal();
private:
    InterProcess *mProcess;
};
#endif // MYAPPLICATION_H

MyApplicaiton.cpp

#include "MyApplication.h"
#include "InterProcess.h"

MyApplication::MyApplication(int &argc, char **argv) : QApplication(argc, argv) {
    mProcess = new InterProcess(this);
    connect(mProcess, SIGNAL(interProcessSignal()),
            this, SLOT(onInterProcessSignal()));
    mProcess->start();
}

void MyApplication::onInterProcessSignal() {}

这是您的 interProcess 类的示例实现：

InterProcess.h

class InterProcess : public QProcess {
    Q_OBJECT
public:
    explicit InterProcess(QObject *parent = nullptr);
signals:
    void interProcessSignal();
private slots:
    void onMainApplicationSignal();
};

InterProcess.cpp

#include "InterProcess.h"
#include "MyApplication.h"


InterProcess::InterProcess(QObject *parent) : QProcess(parent) {
    if(parent) {
        auto myApp = qobject_cast<MyApplication *>(parent);
        if(myApp) {
            connect(myApp, SIGNAL(mainApplicationSignal()),
                    this, SLOT(onMainApplicationSignal()));
        }
    }
}

void InterProcess::onMainApplicationSignal() {}

Answer 2

在本地，使用UDP非常方便高效

void Server::initSocket() {
  udpSocket = new QUdpSocket(this);
  udpSocket->bind(QHostAddress::LocalHost, 7755);
  connect(udpSocket, SIGNAL(readyRead()), this, SLOT(readPendingDatagrams()));}


void Server::readPendingDatagrams(){
  while (udpSocket->hasPendingDatagrams()) {
      QByteArray datagram;
      datagram.resize(udpSocket->pendingDatagramSize());
      QHostAddress sender;
      quint16 senderPort;

      udpSocket->readDatagram(datagram.data(), datagram.size(),
                              &sender, &senderPort);

      processTheDatagram(datagram);
  }}