QSerialPort dont emitted readyRead if window is resizing or moving

Varvara

Hello, help me, please.

I have class for work with some device by COM port. But it dont emitted readyRead if i'm resizing or moving program's window. How solve this problem?

@class Device : public QObject
{
Q_OBJECT

public:
explicit Device(QObject *parent = 0);
~Device();
bool openPort(const QString &portName);
void closePort();
bool isPortOpen() const;
bool sendCommand(unsigned char cmd, unsigned char arg = 0);
bool connectDevice();

private slots:
void onReadData();
void error(QSerialPort::SerialPortError error);

private:
QSerialPort *port;
QByteArray buffer;

signals:
void newDataAvailbled(CurrentData* data);
};@

@Device::Device(QObject *parent) : QObject(parent)
{
...
this->port = new QSerialPort(this);
connect(this->port, SIGNAL(readyRead()), this, SLOT(onReadData()));
}

Device::~Device()
{
this->closePort();
delete this->port;
}

bool Device::openPort(const QString &portName)
{
this->closePort();
this->port->setPortName(portName);
const bool isOpen = this->port->open(QIODevice::ReadWrite);
if (isOpen == true) {
this->port->setBaudRate(QSerialPort::Baud115200);
this->port->setDataBits(QSerialPort::Data8);
this->port->setFlowControl(QSerialPort::NoFlowControl);
this->port->setParity(QSerialPort::NoParity);
this->port->setStopBits(QSerialPort::OneStop);
}
return isOpen;
}

void Device::closePort()
{
if (this->port->isOpen())
this->port->close();
}

bool Device::isPortOpen() const
{
return this->port->isOpen();
}

bool Device::sendCommand(unsigned char cmd, unsigned char arg)
{
if (this->isPortOpen() == false)
return false;
...
QByteArray buf;
if (this->port->write(buf) != buf.size())
return false;
return true;
}

bool Device::connectDevice()
{
return this->sendCommand(DeviceCommands::TurnOffSMode);
}

void Device::onReadData()
{
this->buffer.append(this->port->readAll());
...
emit this->newDataAvailbled(newData);
}@

SGaist

Hi and welcome to devnet,

I would say that the event loop is "blocked" processing the resizing hence the readyRead are not processed while your moving your window. You could move Device in another thread.

@
QThread *serialThread = new QThread(this);
Device *device = new Device;
device->moveToThread(serialThread);
serialThread->start();
// do connections etc...
@

Something like that

Hope it helps

kuzulis

Yes, SGaist is right.

At present the single decision is use of a separate thread. But in the future (for Qt >= 5.x only) is planned to use I/O completion port feature for resolve this problem (but it just ideas on the future).

Varvara

I used moveToThread(), but problem was left((
I'm use windows 7 and Qt5.1

also, if connected readyRead to slot in Device by Qt:AutoConnection, then I have Heap Corruption on reading data. if connect by DirectConnection or BlockingQueuedConnection, then it's OK, but problem with moving of window was left

Varvara

So...
I moved method from signal from readyRead() to timerEvent...
@void Device::timerEvent(QTimerEvent *)
{
int c = port->bytesAvailable();
...
emit testSignal(QTime::currentTime().toString() + " " + QString::number(c));
...
}@

and if I'm moving window, then c is zero, but signal was emitted and I getting current time and zero

Varvara

sorry, I forgot waitForReadyBytes