Independence between dialog and application windows

[tobias.hunger]

http://doc.qt.nokia.com/latest/qdialog.html has lots of information about dialogs in Qt. The section on modal dialogs is of special interest to you.

[RSousa]

Hi,

Thank you for your answers.:)

In fact, I was using exec(). :)
The dialog window is non-modal.
I've changed to show() but the dialog window opens and suddenly closes...
I'm calling this dialog window from a menu.

Could you help me.

Many thanks!

All the best

Ricardo Sousa

[giesbert]

Please show us the code where you show your dialog.
I'm sure, it's pretty easy.
Perhaps, the dialog is creatot on the stack and not by new?

[andre]

If it suddenly closes, perhaps you are creating your item on the stack instead of on the heap?

[ivan.todorovich]

[quote author="Andre" date="1300904949"]If it suddenly closes, perhaps you are creating your item on the stack instead of on the heap?[/quote]

That's exactly my thought

[RSousa]

This is the code....
@
//---
connect(ui->actionSpectrogram,SIGNAL(toggled(bool)),this,SLOT(VerMenuSpectrogram()));

//------
void MainWindow::VerMenuSpectrogram(){

Ui_Spectrogram *ui_Spect;
ui_Spect= new Ui_Spectrogram();
QDialog D;
ui_Spect->setupUi(&D);
D.show();

}
@

I really thank you!

Ricardo Sousa

Edit: Fixed code layout. Please use the @ tags; Andre

[andre]

My diagnoses was correct. You are creating your dialog on the stack instead of on the heap.

[RSousa]

How do you know that...?:)

[andre]

[quote author="RSousa" date="1301053052"]How do you know that...?:)[/quote]

I read the piece of code you posted, of course :-)

Look at line 10 of the snippet you just posted. What happens there? You create a variable called D on the stack. What happens once your code reaches line 13? That variable goes out of scope, and gets removed from the stack again. C++, the nice language it is, thoughtfully calls the destructor for the class in question for you (QDialog). Boom! Your dialog is gone again.

[goetz]

Because he knows the difference between stack and heap allocation. You obviously do not, so time to get some good C++ introduction and learn the basics.

Some keywords for google:

• stack allocation
• heap allocation
• scope of variable

[RSousa]

Now I can see.... it works now.... I'm embarassed .... :)

I need vacations.....

I really thank you for all!

All the best!!!

Ricardo Sousa