Multiple timers problem

jastmc

I want to use two timers to update graphics on the screen. I have two timers. The first is connected to a slot to change the graphic every 150ms and repeat after 10 iterations. The second is to simulate the completion of internal tests every 2 seconds.

There are a couple of problems which I cannot solve. They are in the Dialog module.

My timer->stop(); command crashes the program with a "SIGSEGV" segmentation fault.
My timer2 seems to count up in steps of two rather than one. It skips every second one of the graphics that I give it to display. With the debugger I can stop the code in each state of test but it does not display the graphic.

Could I get some advice please?

Regards,
James

Here is the Dialog module
@#include <QtGui>
#include <QDialog>
#include <QLabel>
#include <QDebug>
#include <QTimer>

#include "dialog.h"
#include "ui_dialog.h"
#include "probe.h"

Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
Dialog::setWindowFlags(Qt::SplashScreen); // no decoration on the screen
ui->setupUi(this);

// Set up the rolling logo timer
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(state_update()));
timer->start(150);

// Set up the test results timer
QTimer *timer2 = new QTimer(this);
connect(timer2, SIGNAL(timeout()), this, SLOT(results_update()));
timer2->start(2000);

}

void Dialog::state_update()
{
static int counter=0;

switch (counter)
{
case 1:
   ui->label->setPixmap(QPixmap(":/logo/logo1.jpg",0,Qt::AutoColor));
    break;
case 2:
   ui->label->setPixmap(QPixmap(":/logo/logo2.jpg",0,Qt::AutoColor));
    break;
case 3:
   ui->label->setPixmap(QPixmap(":/logo/logo3.jpg",0,Qt::AutoColor));
    break;
case 4:
   ui->label->setPixmap(QPixmap(":/logo/logo4.jpg",0,Qt::AutoColor));
    break;
case 5:
   ui->label->setPixmap(QPixmap(":/logo/logo5.jpg",0,Qt::AutoColor));
    break;
case 6:
   ui->label->setPixmap(QPixmap(":/logo/logo6.jpg",0,Qt::AutoColor));
    break;
case 7:
   ui->label->setPixmap(QPixmap(":/logo/logo7.jpg",0,Qt::AutoColor));
    break;
case 8:
   ui->label->setPixmap(QPixmap(":/logo/logo8.jpg",0,Qt::AutoColor));
    break;
case 9:
   ui->label->setPixmap(QPixmap(":/logo/logo9.jpg",0,Qt::AutoColor));
    break;
case 10:
   ui->label->setPixmap(QPixmap(":/logo/logo10.jpg",0,Qt::AutoColor));
    break;
}

if (++counter > 10) counter = 1;

}

void Dialog::results_update()
{
static int test = 0;
QString str;

switch (test)
{
    case 0:
        ui->label_Clk_Result->setPixmap(QPixmap(":/logo/Pass.jpg",0,Qt::AutoColor));
        break;
    case 1:
        ui->label_USB_Result->setPixmap(QPixmap(":/logo/Pass.jpg",0,Qt::AutoColor));
        break;
    case 2:
        ui->label_Probe_Result->setPixmap(QPixmap(":/logo/Pass.jpg",0,Qt::AutoColor));
        break;
    case 3:
        ui->label_HV_Result->setPixmap(QPixmap(":/logo/Fail.jpg",0,Qt::AutoColor));
        break;
    case 4:
        ui->label_LV_Result->setPixmap(QPixmap(":/logo/Pass.jpg",0,Qt::AutoColor));
        break;
    case 5:
        break;
    case 6:
        timer->stop();

// timer2->stop();

        Probe *j = new Probe();
        j->showMaximized();
        this->close();

        break;

}
test++;
str = QString("Test = %1").arg(test);
ui->label_test->setText(str);

}

Dialog::~Dialog()
{
delete ui;
}

void Dialog::on_buttonBox_accepted()
{
qApp->quit();
}

@

Here is the Main module
@#include "dialog.h"
#include "probe.h"
#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Dialog w;
Dialog Probe;

w.show();

return a.exec&#40;&#41;;

}
@

Here is the Probe module
@#include "probe.h"
#include "ui_probe.h"

Probe::Probe(QWidget *parent) :
QDialog(parent),
ui(new Ui::Probe)
{
Probe::setWindowFlags(Qt::SplashScreen); // no decoration on the screen
ui->setupUi(this);
}

Probe::~Probe()
{
delete ui;
}

void Probe::on_buttonBox_accepted()
{
qApp->quit();
}
@

Here is Dialog.h
@#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QtGui>

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
Q_OBJECT

public:
explicit Dialog(QWidget *parent = 0);
~Dialog();

private slots:
void on_buttonBox_accepted();
void state_update();
void results_update();

private:
Ui::Dialog *ui;
QDialogButtonBox *buttonBox;
QTimer *timer;
QTimer *timer2;

signals:

};

#endif // DIALOG_H
@

Here is Probe.h
@#ifndef PROBE_H
#define PROBE_H

#include <QDialog>

namespace Ui {
class Probe;
}

class Probe : public QDialog
{
Q_OBJECT

public:
explicit Probe(QWidget *parent = 0);
~Probe();

private slots:
void on_buttonBox_accepted();

private:
Ui::Probe *ui;
};

#endif // PROBE_H
@

SGaist

Hi,

You shadowed both your Dialog timer variable in the constructor so it's no initialized.
Try this:
@
timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(state_update()));
timer->start(150);

timer2 = new QTimer(this);
connect(timer2, SIGNAL(timeout()), this, SLOT(results_update()));
timer2->start(2000);

@

I would recommend to change the class variables naming with something like _timer or m_timer. It helps separating local variables from class variable.

Hope it helps

jastmc

Hi,

Sorry but being new to Qt, I don't understand what you mean by
[quote]You shadowed both your Dialog timer variable in the constructor so it’s no initialized.
[/quote]

Can you explain or point me to something where I can learn about this?

Regards,
James

jastmc

Hi,

Thanks for your suggestion, that helped with the crashing problem.

Any ideas about the counting up in twos?

Regards
James

mlong

[quote author="jastmc" date="1366645117"]Hi,

Sorry but being new to Qt, I don't understand what you mean by
[quote]You shadowed both your Dialog timer variable in the constructor so it’s no initialized.
[/quote]

Can you explain or point me to something where I can learn about this?
[/quote]

http://en.wikipedia.org/wiki/Variable_shadowing