Question about using of static QTimer::singleShot() function

[another_one]

Hello!

I'm trying to use the static QTimer::singleShot() function to create delay between write and read cycles via serial interface.

I have done the following code:

Hedaer:

#ifndef CAN_TRANSFER_H
#define CAN_TRANSFER_H
 
#include <QMainWindow>
#include "qextserialport.h"
#include <Qtimer.h>
 
 
namespace Ui {
    class CAN_transfer;
 
}
 
class CAN_transfer : public QMainWindow {
    Q_OBJECT
 
public:
    CAN_transfer(QWidget *parent = 0);
    ~CAN_transfer();
 
 
protected:
    void changeEvent(QEvent *e);
 
private:
    Ui::CAN_transfer *ui;
    QextSerialPort*  _comPort; 
    unsigned char mas[64];
    unsigned char* DATA_pointer;
 
private slots:
 
    void readBR(unsigned char t);
    void on_store_all_button_clicked();
    void on_store_sel_button_clicked();
    void on_connectbutton_clicked();
    void timer_event();
};
 
#endif // CAN_TRANSFER_H

#ifndef CAN_TRANSFER_H
#define CAN_TRANSFER_H

#include <QMainWindow>
#include "qextserialport.h"
#include <Qtimer.h>


namespace Ui {
    class CAN_transfer;

}

class CAN_transfer : public QMainWindow {
    Q_OBJECT

public:
    CAN_transfer(QWidget *parent = 0);
    ~CAN_transfer();


protected:
    void changeEvent(QEvent *e);

private:
    Ui::CAN_transfer *ui;
    QextSerialPort*  _comPort; 
    unsigned char mas[64];
    unsigned char* DATA_pointer;

private slots:

    void readBR(unsigned char t);
    void on_store_all_button_clicked();
    void on_store_sel_button_clicked();
    void on_connectbutton_clicked();
    void timer_event();
};

#endif // CAN_TRANSFER_H

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Source:

#include "can_transfer.h"
#include "ui_can_transfer.h"
#include "qextserialport.h"
#include "win_qextserialport.h"
//#include <Qtimer.h>
#include <QTimer>
unsigned char clkdt,te;
CAN_transfer::CAN_transfer(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::CAN_transfer)
{
    ui->setupUi(this);
    ui->logw->setReadOnly(true);
    ui->logw->setFontWeight(QFont::Bold);
    ui->logw->append(tr("CAN transfer configurator is ready to use!"));
    ui->logw->setFontWeight(QFont::QFont::Normal);
    ui->logw->setTextColor(Qt::black);
    QString s="COM1";
    _comPort  = new QextSerialPort(s);
    _comPort->setBaudRate(BAUD9600);
    _comPort->setFlowControl(FLOW_OFF);
    _comPort->setParity(PAR_NONE);
    _comPort->setDataBits(DATA_8);
    _comPort->setStopBits(STOP_1);
    DATA_pointer = &mas[0];
    clkdt = 0;
}
 
CAN_transfer::~CAN_transfer()
{
    _comPort->close();
    delete(_comPort);
    delete ui;
}
 
void CAN_transfer::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}
 
 
void CAN_transfer :: timer_event()
{
    te = 0;
    timer->stop();
}
void CAN_transfer::on_connectbutton_clicked()
{unsigned char rb=0;
    ui->logw->append(tr("COM1 configurating...."));
     _comPort->open(QIODevice::ReadWrite | QIODevice::Unbuffered);
    ui->logw->append(tr("conneting...."));
    *DATA_pointer = 0x55;
    if(_comPort->write((const char*)DATA_pointer, 1))
    {
 
        te = 1;
        QTimer :: singleShot(100, this, SLOT(timer_event()));
        while(te);
        rb = _comPort->bytesAvailable();
        if(rb)
        {
            _comPort->read((char*)DATA_pointer,rb);
            if(*DATA_pointer==0xAA)
            ui->logw->append(tr("connection established!"));
        }
        else
        {
            ui->logw->append(tr("no connection"));
        }
 
    }
 
    statusBar()->showMessage(tr("Connected"));
    //_comPort->close();
}

#include "can_transfer.h"
#include "ui_can_transfer.h"
#include "qextserialport.h"
#include "win_qextserialport.h"
//#include <Qtimer.h>
#include <QTimer>
unsigned char clkdt,te;
CAN_transfer::CAN_transfer(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::CAN_transfer)
{
    ui->setupUi(this);
    ui->logw->setReadOnly(true);
    ui->logw->setFontWeight(QFont::Bold);
    ui->logw->append(tr("CAN transfer configurator is ready to use!"));
    ui->logw->setFontWeight(QFont::QFont::Normal);
    ui->logw->setTextColor(Qt::black);
    QString s="COM1";
    _comPort  = new QextSerialPort(s);
    _comPort->setBaudRate(BAUD9600);
    _comPort->setFlowControl(FLOW_OFF);
    _comPort->setParity(PAR_NONE);
    _comPort->setDataBits(DATA_8);
    _comPort->setStopBits(STOP_1);
    DATA_pointer = &mas[0];
    clkdt = 0;
}

CAN_transfer::~CAN_transfer()
{
    _comPort->close();
    delete(_comPort);
    delete ui;
}

void CAN_transfer::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}


void CAN_transfer :: timer_event()
{
    te = 0;
    timer->stop();
}
void CAN_transfer::on_connectbutton_clicked()
{unsigned char rb=0;
    ui->logw->append(tr("COM1 configurating...."));
     _comPort->open(QIODevice::ReadWrite | QIODevice::Unbuffered);
    ui->logw->append(tr("conneting...."));
    *DATA_pointer = 0x55;
    if(_comPort->write((const char*)DATA_pointer, 1))
    {

        te = 1;
        QTimer :: singleShot(100, this, SLOT(timer_event()));
        while(te);
        rb = _comPort->bytesAvailable();
        if(rb)
        {
            _comPort->read((char*)DATA_pointer,rb);
            if(*DATA_pointer==0xAA)
            ui->logw->append(tr("connection established!"));
        }
        else
        {
            ui->logw->append(tr("no connection"));
        }

    }

    statusBar()->showMessage(tr("Connected"));
    //_comPort->close();
}

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The problem is in that what application do not affect the SLOT(event_timer) code, at least it seems to be.

Compiler don not issue any warning or errors and I casue of that I don't understand in what the problem is.

I need some help to solve this problem, I would glad of any information about it.


Thanks in advance

[franz]

Why not use the QThread::msleep() function for that?

[Lesiok]

Problem is with line 65. With this construction You disable event dispatcher. Yours loop must be like this :

while(te)
    QCoreApplication::processEvents();

while(te)
    QCoreApplication::processEvents();

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[another_one]

Problem is with line 65. With this construction You disable event dispatcher. Yours loop must be like this :

while(te)
    QCoreApplication::processEvents();

while(te)
    QCoreApplication::processEvents();

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Thank You very much, finally it works!