[Qt-interest] the problem of QProgressDialog & QProgressBar

[Gan Xiebin]

Malyushytsky, Alex wrote:
> Because of    p_ShowSysInfoDlg->exec(); I guess.
>
> I don’t think event loop of application is running when you open another
> modal dialog.
>

John McClurkin wrote:
> Alex is correct. calling p_ShowSysInfoDialog->exec() blocks the
> application until it returns. If you want the progress dialog to show
> progress during the execution of the SysInfoDialog, create the progress
> dialog first on the heap and pass a pointer to the SysInfoDialog
> constructor. Then, in the SysInfoDialog exec function, update the
> progress dialog periodically and call QApplication::processEvents().

> I forgot to add that you show() the progress dialog in the SysInfoDialog.


Thanks Alex and John.

OK. The exec() blocks the application until it returns.
But although I create the progress dialogue and pass a pointer to the
SysInfoDialog constructor,
the GUI thread still blocks while I used wait() in the event loop, right ?
What should I do ?
Any reply is welcome. Thanks.

-------------------------------------------------
void MainWindow::SysInfoFunc()
{

    progressDlg = new QProgressDialog("Operation in progress.", "Cancel", 0,
100, this);

    SysInfoDlg *p_ShowSysInfoDlg = new SysInfoDlg(node, progressDlg);
    p_ShowSysInfoDlg->exec();

}

ysInfoDlg::SysInfoDlg(Node *node, QProgressDialog *progressDlg, QWidget
*parent)
    : QDialog( parent )
{
    this->progressDlg = progressDlg;
    this->progressDlg->setValue(0);

    timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(performProgressDlg()));
    timer->start(1000);

    this->progressDlg->show();
    QApplication::processEvents();

// set text
  textLabel = new QLabel();

  thread1.start();  // A task
  thread2.start();  // Another task

  thread1.wait(); // wait for task finished, and set text to the label
  thread2.wait(); // like thread1 ...

  textLabel->setText( ... );

// close dialog
    timer->stop();
    this->progressDlg->close();
}

void SysInfoDlg::performProgressDlg()
{
    if(progressDlg->value() + 1 < progressDlg->maximum())
    {
        progressDlg->setValue(progressDlg->value() + 1);
    }
    else
    {
        timer->stop();
        progressDlg->close();
    }
    progressDlg->show();
    QApplication::processEvents();
}

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