我实现了一个类,它可以通过QQueue将数据写入串口并通过插槽读取.我使用QAsyncSerial来反过来使用boost :: asio和回调.
该类被移动到一个线程,并且当QThread发出“started()”时执行其start()方法
该类被移动到一个线程,并且当QThread发出“started()”时执行其start()方法
问题是我使用forever {}和QWaitCondition在start()方法中将QQueue出列.当它正在运行时(显然会永远运行),无法调用连接到QAsyncSerial的dataReceived信号的插槽,因此我从未从串行端口读取任何内容.
SerialPortHandler::SerialPortHandler(SerialPort serialPort,QObject *parent) : QObject(parent),serialPort(serialPort)
{
m_enqueueMessageMutex = new QMutex();
m_messageQueue = new QQueue<BaseMessage*>();
m_waitCondition = new QWaitCondition();
serial.open(serialPort.deviceName(),2400);
connect(&serial,SIGNAL(dataReceived(QByteArray)),this,SLOT(serialSlotReceivedData(QByteArray)));
}
void SerialPortHandler::serialSlotReceivedData(QByteArray line)
{
qDebug() << QString(line).toAscii();
}
void SerialPortHandler::sendTestPing()
{
PingMessage *msg = new PingMessage();
enqueueMessage(msg);
}
void SerialPortHandler::enqueueMessage(BaseMessage *msg)
{
QMutexLocker locker(m_enqueueMessageMutex);
m_messageQueue->enqueue(msg);
m_waitCondition->wakeAll();
}
void SerialPortHandler::start()
{
if (!serial.isOpen())
return;
forever {
m_enqueueMessageMutex->lock();
if (m_messageQueue->isEmpty())
m_waitCondition->wait(m_enqueueMessageMutex);
BaseMessage *msg = m_messageQueue->dequeue();
serial.write(msg->encodeForWriting());
m_enqueueMessageMutex->unlock();
}
}
boost :: asio使用的更改的QAsyncSerial回调：
void QAsyncSerial::readCallback(const char *data,size_t size)
{
emit dataReceived(QByteArray::fromRawData(data,(int) size));
}
编辑：
我用另一种方法解决了这个问题.我抛弃了QAsyncSerial,而是使用了CallbackAsyncSerial,它也是由QAsyncSerial直接分发的.现在boost :: asio使用的回调是serialSlotReceivedData“slot”.这“解决”了这个问题,因为在线程boost :: asio运行中调用了回调.因为它有自己的线程,所以ThreadPortHandler运行的线程被永久循环阻塞并不重要.
新代码:(因为QAsyncSerial类似于CallbackAsyncSerial的包装,只有一些微不足道的事情发生了变化)
SerialPortHandler::SerialPortHandler(SerialPort serialPort,serialPort(serialPort)
{
m_enqueueMessageMutex = new QMutex();
m_messageQueue = new QQueue<BaseMessage*>();
m_waitCondition = new QWaitCondition();
/* serial is now CallbackAsyncSerial and not QAsyncSerial */
serial.open(QString(serialPort.deviceName()).toStdString(),2400);
serial.setCallback(bind(&SerialPortHandler::serialSlotReceivedData,_1,_2));
m_messageProcessingState = MessageProcessingState::Inactive;
}
void SerialPortHandler::start()
{
if (!serial.isOpen())
return;
forever {
m_enqueueMessageMutex->lock();
if (m_messageQueue->isEmpty())
m_waitCondition->wait(m_enqueueMessageMutex);
BaseMessage *msg = m_messageQueue->dequeue();
QByteArray encodedMessage = msg->encodeForWriting();
serial.write(encodedMessage.constData(),encodedMessage.length());
m_enqueueMessageMutex->unlock();
}
}
解决方法
1)在你的线程中创建插槽,例如onMessageReady(),它将完成这项工作.
2)创建一个信号表示新消息准备就绪,并在每次创建新消息时发出.
3)使用QueuedConnection连接它们并调用线程的exec函数.
这不会像WaitforObject那样阻塞你的线程,你将处理所有传入的信号.
像这样的东西：
SerialPortHandler: public QThread
{
Q_OBJECT
...
signals:
void sNewMessageReady();
slots:
void onNewMessageReady();
void serialSlotReceivedData(QByteArray);
};
SerialPortHandler::SerialPortHandler(SerialPort serialPort,QObject *parent) : QThread(parent),serialPort(serialPort)
{
m_enqueueMessageMutex = new QMutex();
m_messageQueue = new QQueue<BaseMessage*>();
serial.open(serialPort.deviceName(),SLOT(serialSlotReceivedData(QByteArray)));
connect(this,SIGNAL(sNewMessageReady()),SLOT(onNewMessageReady()),Qt::QueuedConnection);
}
void SerialPortHandler::enqueueMessage(BaseMessage *msg)
{
QMutexLocker locker(m_enqueueMessageMutex);
m_messageQueue->enqueue(msg);
emit sNewMessageReady();
}
void SerialPortHandler::onNewMessageReady()
{
QMutexLocker locker(m_enqueueMessageMutex);
BaseMessage *msg = m_messageQueue->dequeue();
serial.write(msg->encodeForWriting());
}
