[PyQt] QMessagebox in slot terminates application

[Darryl Wallace]

Tim,

This is the more accurate explanation I was looking for!

darryl
Tim Hoffmann wrote:
> Marc Nations schrieb:
>> Yeah, that's more correct. Since the MessageBox is being called 
>> indirectly the actual value it returns isn't being utilized.
>>
>> Although now I'm a little confused as to why the app is even 
>> returning a value when the MessageBox is closed. Even if you take 
>> sys.exit() out and just print out the value the app returns, it will 
>> still exit. Basically the whole app acts like a DialogBox that gets 
>> triggered by the MessageBox.
>>
>> I'm not sure I fully understand what all the exec() function does.
> int QApplication.exec_() :
> Enters the main event loop and waits until exit() is called, then 
> returns the value that was set to exit()
>
> QMessageBox.information() should call the inherited QDialog.exec_() 
> which installs a local event loop, because the dialog is modal.
>
>
> I found out what's happening:
> Closing the QMessageBox is something like QDialog.done(). This emitts 
> a QApplication.lastWindowClosed() signal if the dialog is the last 
> window. Because of the default app.quitOnLastWindowClosed == True 
> exit() will be called for the main loop and the application terminates 
> regularly.
>
> So by adding app.setQuitOnLastWindowClosed(False) the application does 
> not terminate any more.
>
> Tim
>