qt window close but process still running

[sazzad08]

ok, I have changed my code and it is like this now;

QTMainForm::QTMainForm(QWidget* parent)
{

btn.setText("Start");
connect(&btn, SIGNAL(clicked()), this, SLOT(OnBtnstrt()));
progress.setValue(0);

progress.setRange(0, 1000000);

vb.addWidget(&progress);
vb.addWidget(&btn);
setLayout(&vb);
}

void QTMainForm::OnBtnstrt()
{
double i=0;
while(i<=1000000)
{
i++;
qApp->processEvents();

progress.setValue(i);
}
}

still the same problem occurs. As I was observing if I put the value of "i" 1000000 the process stop when I close the window but if I put the value of "i" >1000000 then the problem occurs. any suggestions?

[Santosh Reddy]

Can you post a compilable code...

1. I am still guessing QTMainForm is QWidget/QMainWindow ?
2. How and where you are creating QTMainForm ?
3. Did to follow suggestion by d_stranz above

[sazzad08]

yes. you are right. this is my full code

class QTMainForm : public QWidget
{
Q_OBJECT

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



private slots:

void OnBtnstrt();
// void closer();
// DWORD WINAPI SocketHandler(void*);

private:

QProgressBar progress;
QPushButton btn;

//QVBoxLayout vboxMainLayout;
QVBoxLayout vb;

};


QTMainForm::QTMainForm(QWidget* parent)
{

btn.setText("Start");
connect(&btn, SIGNAL(clicked()), this, SLOT(OnBtnstrt()));
progress.setValue(0);

progress.setRange(0, 10000000);

vb.addWidget(&progress);
vb.addWidget(&btn);
setLayout(&vb);
}

void QTMainForm::OnBtnstrt()
{
double i=0;
while(i<=10000000)
{
i++;
qApp->processEvents();

progress.setValue(i);

}
}

QTMainForm::~QTMainForm()
{

}


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

QTMainForm* pMainForm = 0;

QApplication app(argc, argv);
pMainForm = new QTMainForm();
pMainForm->resize(300, 300);
pMainForm->show();
return app.exec();
}

[Santosh Reddy]

Not sure what is your long term goal, whatever it be using such a for loop(> 10000000) in button click (or any other slot) will land in to various issues.\

For now to solve the problem, just modify the button click slot

void QTMainForm::OnBtnstrt()
{
    double i=0;
    while(i<=10000000)
    {
        i++;
        qApp->processEvents();
 
        progress.setValue(i);
 
        if(!isVisible()) // <<<<<<<<<<<<<<<<<<<<<
            break;
    }
}

void QTMainForm::OnBtnstrt()
{
    double i=0;
    while(i<=10000000)
    {
        i++;
        qApp->processEvents();

        progress.setValue(i);

        if(!isVisible()) // <<<<<<<<<<<<<<<<<<<<<
            break;
    }
}

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One more observation in the main, pMainForm is not being deleted, this is a leak in memory (it will not be a concern now, as the app exits anyway). As a good practice (in Qt) always pass the parent handle to the base classs QWidget/QObject

QTMainForm::QTMainForm(QWidget* parent)
    : QWidget(parent) // <<<<<<<<<<<<<<<<<<<<<<<<<<<
{
...
}

QTMainForm::QTMainForm(QWidget* parent)
    : QWidget(parent) // <<<<<<<<<<<<<<<<<<<<<<<<<<<
{
...
}

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[sazzad08]

it works great. thanks a lot.