Windows下QT实现串口热插拔

在Windows下实现串口热插拔，需要通过Windows API来监测串口的插拔事件并做出相应处理。下面是一个使用QT实现串口热插拔的示例代码：

#include <QCoreApplication>
#include <QtSerialPort/QSerialPort>
#include <QObject>
#include <QDebug>
#include <windows.h>

//定义一个继承自QObject的类，用于处理串口插拔事件
class SerialPortWatcher : public QObject
{
    Q_OBJECT

public:
    SerialPortWatcher(QObject *parent = nullptr) : QObject(parent) {}

signals:
    void serialPortAdded(QString portName);     //定义串口插入信号
    void serialPortRemoved(QString portName);   //定义串口拔出信号

public slots:
    void checkSerialPorts()     //检测串口列表
    {
        QStringList currentSerialPortList = getSerialPortList();     //获取当前串口列表

        for (int i = 0; i < currentSerialPortList.size(); i++)
        {
            if (!m_serialPortList.contains(currentSerialPortList[i]))     //如果当前串口列表中有新串口
            {
                emit serialPortAdded(currentSerialPortList[i]);     //发射串口插入信号
            }
        }

        for (int i = 0; i < m_serialPortList.size(); i++)
        {
            if (!currentSerialPortList.contains(m_serialPortList[i]))     //如果当前串口列表中有串口被拔出
            {
                emit serialPortRemoved(m_serialPortList[i]);     //发射串口拔出信号
            }
        }

        m_serialPortList = currentSerialPortList;     //更新串口列表
    }

private:
    QStringList getSerialPortList()     //获取当前串口列表
    {
        QStringList serialPortList;

        for (int i = 1; i <= 255; i++)
        {
            QString portName = QString("COM%1").arg(i);

            HANDLE handle = CreateFileA(portName.toStdString().c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
            if (handle != INVALID_HANDLE_VALUE)
            {
                CloseHandle(handle);
                serialPortList.append(portName);
            }
        }

        return serialPortList;
    }

    QStringList m_serialPortList;     //保存当前串口列表
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QSerialPort serialPort;

    SerialPortWatcher *serialPortWatcher = new SerialPortWatcher(&a);     //创建串口监测对象

    QObject::connect(serialPortWatcher, &SerialPortWatcher::serialPortAdded, [&serialPort](QString portName)
    {
        qDebug() << "Serial Port Added: " << portName;

        if (!serialPort.isOpen())     //如果串口没有打开，就打开新插入的串口
        {
            serialPort.setPortName(portName);
            serialPort.setBaudRate(QSerialPort::Baud115200);
            serialPort.setParity(QSerialPort::NoParity);
            serialPort.setDataBits(QSerialPort::Data8);
            serialPort.setStopBits(QSerialPort::OneStop);
            if (serialPort.open(QIODevice::ReadWrite))
            {
                qDebug() << "Serial Port Opened: " << portName;
            }
        }
    });

    QObject::connect(serialPortWatcher, &SerialPortWatcher::serialPortRemoved, [&serialPort](QString portName)
    {
        qDebug() << "Serial Port Removed: " << portName;

        if (serialPort.isOpen() && serialPort.portName() == portName)     //如果串口已经打开，并且是当前拔出的串口，就关闭串口
        {
            serialPort.close();
            qDebug() << "Serial Port Closed: " << portName;
        }
    });

    QTimer *timer = new QTimer(&a);
    timer->setInterval(1000);     //设置定时器时间间隔为1秒
    timer->start();

    QObject::connect(timer, &QTimer::timeout, serialPortWatcher, &SerialPortWatcher::checkSerialPorts);     //连接定时器与串口监测对象的检测方法

    return a.exec();
}

#include "main.moc"

上述代码中，我们创建了一个继承自QObject的类SerialPortWatcher，通过Windows API获取当前串口列表，并定时检测串口列表的变化，如果有串口插入或拔出，就发射相应的信号。在主函数中，我们连接SerialPortWatcher的信号与串口打开和关闭的槽函数，实现自动打开和关闭串口。最后，我们启动事件循环，定时检测串口列表的变化。