After some other tests, I think I've found which is the issue and how to solve it.
Here a simplified snippet of my code, where there is a class Button used by a class Parent.
When button is clicked, it could cause a panel change, or raise a message, or do some other actions (not detailed beause not relevant to the question).
What I found is in slot onClicked of class Button: entering the first if, the program emits the signal request_GoToPrev, which cause the class Panel to delete current panel (and its childs, even compirsed the Button!) and raise a new one.
But after emitting the signal and do all actions required, the program "comes back" to the point when it has emitted the signal and continue the instruction execution: when it reaches the second if it creashes because this is no more consistent.
That's what it seems to be after my tests. Putting a return call just after the signal emission in the first if problem is solved.
// HEADER: Button.h
class Button : public QPushButton
{
Q_OBJECT
public:
Button( QWidget *parent = 0 );
~Button();
signals:
void request_GoToPrev(); //!< Go to previous panel
void request_GoToNext( QString ); //!< Go to next panel
void signal_Error( int ); //!< Error code
private slots:
void onClicked();
private:
typ_Button_tags *widgetTags; //!< Pointer to the tags structure that defines the \ref Button widget
typ_Shared *privateCtx; //!< Reference to runtime application structure
};
// C: Button.cpp
Button::Button( QWidget *parent )
:
QPushButton(parent)
{
// Do some settings, like: font, stylesheet, focus, size..
}
Button::~Button()
{
}
void Button::onClicked()
{
// Callback to be called when button clicked
if( !this->widgetTags->callbackClick.isEmpty() )
{
emit this->request_GoToPrev();
/* !!! ATTENTION !!!
*
* Here the instruction return HAS to be written, otherwise the application crashes.
* In fact, when running, the signal 'request_GoToPrev' is sent, but the flow of the
* process should exit the call of this slot.
* Doing that, 'this' is no more consistent after having emitted the signal, so the
* application face a segmentation fault.
*/
return;
}
// Message box
if( !this->widgetTags->msgText.isEmpty() )
{
// Do some other actions on 'this'...
}
}
// HEADER: Panel.h
class Panel : public QMainWindow
{
Q_OBJECT
public:
Panel( QWidget *parent = 0 );
private slots:
void on_GoToNext(int index);
void on_GoToPrevious();
void on_Error(int errId);
private:
Button *Btn;
};
// C: Panel.h
Panel::Panel( QWidget *parent )
:
QMainWindow(parent)
{
// Do some settings: font, stylesheet, focus, size...
this->Btn = new Button( this );
connect( this->Btn, SIGNAL(request_GoToPrev()), this, SLOT(on_GoToPrevious()), Qt::UniqueConnection );
// Do some actions to layout the button inside the panel
}
void Panel::on_GoToPrevious()
{
// Do some check...
delete this->Btn;
// Do some actions...
}
