Question

So i have a program that uses a subclass of QMainWindow for QMdiArea widgets. I’m only doing this because QDockWidgets can only be used in a QMainWindow (and my subclass needed dock widgets).

I was testing my class’s serialization for saving purposes and my pointer wasn’t correct. Here is the code

    if (ui->mdiMain->subWindowList().length() > 0)
    {
        QString path = QFileDialog::getSaveFileName(this, "Save Build Order", "" ,"*.cbo");

        if (path > 0)
        {
            QFile file(path, this);
            if (file.open(QFile::WriteOnly) == true)
            {
                QWidget* widget = reinterpret_cast<QWidget*>(ui->mdiMain->activeSubWindow());
                WidgetBuildOrder* widgetBuildOrder = reinterpret_cast<WidgetBuildOrder*>(widget);

                QDataStream stream(&file);
                stream << widgetBuildOrder;

                file.close();
                ui->statusBar->showMessage("Save Successful.", 5000);
            }
        }

    }
}

WidgetBuildOrder is a subclass of MainWindow.

so my thought was that I could keep casting the pointer to what it actually is. When I created the MDI area, i passed a new WidgetBuildOrder. Is there a way to do this?

To Clarify, after the casting I do get a pointer its just pointing to garbage. Not the values set in the WidgetBuildOrder I actually have open.

Any help will be appreciated,

Thanks,

Jec

Answer 1

QMdiArea::activeSubWindow returns a QMdiSubWindow*, or 0 it the QMdiArea doesn’t have the focus.

As you can’t possibly have a class that inherits from QMainWindow and QMdiSubWindow, what you want is to get the widget inside the current sub-window:

QMdiSubWindow *subWindow = ui->mdiMain->currentSubWindow();
WidgetBuildOrder* widgetBuildOrder = 
    static_cast<WidgetBuildOrder*>(subwindow->widget());