Close / Stop MDIChild in its constructor

pixbyte

I want to avoid to see empty data tables in my app. So I want to stop MDIChild creation while it is created.
As sample:

MdiChildDiskInfo::MdiChildDiskInfo(QWidget* parent, const QString &device)
    :strBurnDrive(device){
      setAttribute(Qt::WA_DeleteOnClose);

      readDiskInfo();

}

void MdiChildDiskInfo::readDiskInfo()
{
   int nError = 0;
   .....
   if( nError == 1 ) this->parentWidget()->close();
}

The problem here is, if I run this code the whole app is closed. Without parentWidget() it leaves empty dialogs. So how can I programmatically stop MDIChild creation?

JonB

@pixbyte
What "dialogs", there are no dialogs here? The code should probably be one of

if( nError == 1 ) this->close();
if( nError == 1 ) this->hide();

Maybe it does not like you closing/hiding from the constructor, I don't know. Temporarily try it from elsewhere to test.

You might also want to read e.g. https://www.qtcentre.org/threads/12409-Close-a-QMdiSubwindow . I'm not sure if it relates to what you see.

pixbyte

Dialog or widgets...I think everyone knows what I mean.

mrjj

@pixbyte said in Close / Stop MDIChild in its constructor:

Dialog or widgets...I think everyone knows what I mean.

Yep, but for dialogs, there are Accept and Reject etc so in some use cases its really not the same :)
Anyway

if whole application closes, please try setting
setQuitOnLastWindowClosed(false); on the application.
https://doc.qt.io/qt-5/qguiapplication.html#quitOnLastWindowClosed-prop
and see if that is what you are experiencing.

That said, its really not super to try to cancel construction from within the ctor.
However, it should work. ( i think)

Is there a reason you cant just do

bool MdiChildDiskInfo::readDiskInfo() .. <<< let it return a status if empty or not

MdiChildDiskInfo * di = new MdiChildDiskInfo(..)
if (! di->readDiskInfo() )
di->DeleteLater(); // nothing to show get rid of it
else
di->show();
(psudo code)