Event handling problem

[Mel Seyle]

I'm trying to get an object to handle a QCloseEvent. The object, DDS, is instantiated in Main_Widget, and pops up as a smaller window. In this case all the close event in the new DDS object is supposed to do is execute a printf that shows that closeEvent was indeed called. However, when the DDS object is closed, it appears that closeEvent is never called. Note that a similar closeEvent in Main_Widget will execute its printf, and the desired message appears.

I'm missing something fundamental here, but haven't been able to track it down.

Thanks.

Mel Seyle

code follows:

#include <qapplication.h>
#include <qfontdatabase.h>
#include "main_widget.h"
#include "app.xpm"
 
//int DDS::loLcdValue=0;
 
int main (int argc, char **argv)
{
    QApplication app(argc, argv);
    Main_Widget *w = new Main_Widget;; 
    app.setWindowIcon( QIcon(app_xpm) );
    app.setStyleSheet("QFrame {border : 1px solid rgb(255,200,55)}"); 
    w->show();
    return app.exec();
}
 
#include "main_widget.h"
 
Main_Widget::Main_Widget(QWidget *parent)
        : QWidget(parent)
{
    setDds( 5 );
}
 
void Main_Widget::closeEvent( QCloseEvent * )
{
    printf("Main_Widget::closeEvent\n");
    finish();
}
 
void Main_Widget::finish()
{
//    saveSettings();
    exit( 0 );
}
 
void Main_Widget::setDds( int )
{
    SDR_ShellDDS = new DDS;          
}
 
 
#ifndef SDXCVR_MAINWIDGET_H
#define SDXCVR_MAINWIDGET_H
 
#include <qwidget.h>
#include <qapplication.h>
 
#include "DDS.h"
 
class Main_Widget : public QWidget
{
 
 
 Q_OBJECT
 
 private:
    DDS *SDR_ShellDDS; 
 
 public:
    Main_Widget(QWidget *parent = 0);    
 
 public slots:
    void finish();   
    void setDds( int );
 
 protected: 
    void closeEvent( QCloseEvent * );
 
};
#endif
 
 
#include "DDS.h"
 
DDS::DDS( QWidget *parent) 
	: QWidget( parent)
{
 
    ddsFrame = new QFrame();
    ddsFrame->setGeometry( 400, 200, 450, 300 );
    ddsFrame->setMinimumWidth( 450 );
    ddsFrame->setMinimumHeight( 300 );
    ddsFrame->setWindowTitle("SDR-Shell : Frequency Control ");
 
    ddsFrame->show();
 
}
 
void DDS::closeEvent( QCloseEvent *e )
{
printf("closeEvent( QCloseEvent * )\n");
    e->accept();
    finish();
}
 
void DDS::finish()
{
printf("finish()\n");
//   exit( 0 );
}
 
 
#ifndef DDS_H
#define DDS_H
 
#include <QWidget>
#include <QFrame>
#include <QCloseEvent>
#include <QEvent>
#include <QAction>
#include <QObject>
 
 
class DDS : public QWidget
{
    Q_OBJECT
 
 
    private:
 
        QFrame *ddsFrame;
 
    public:
 
        DDS(QWidget *parent = 0);
 
    private slots:
 
        void finish();
 
    protected:
        void closeEvent( QCloseEvent * );
 
};
#endif

#include <qapplication.h>
#include <qfontdatabase.h>
#include "main_widget.h"
#include "app.xpm"

//int DDS::loLcdValue=0;

int main (int argc, char **argv)
{
    QApplication app(argc, argv);
    Main_Widget *w = new Main_Widget;; 
    app.setWindowIcon( QIcon(app_xpm) );
    app.setStyleSheet("QFrame {border : 1px solid rgb(255,200,55)}"); 
    w->show();
    return app.exec();
}

#include "main_widget.h"

Main_Widget::Main_Widget(QWidget *parent)
        : QWidget(parent)
{
    setDds( 5 );
}

void Main_Widget::closeEvent( QCloseEvent * )
{
    printf("Main_Widget::closeEvent\n");
    finish();
}

void Main_Widget::finish()
{
//    saveSettings();
    exit( 0 );
}

void Main_Widget::setDds( int )
{
    SDR_ShellDDS = new DDS;          
}


#ifndef SDXCVR_MAINWIDGET_H
#define SDXCVR_MAINWIDGET_H

#include <qwidget.h>
#include <qapplication.h>

#include "DDS.h"

class Main_Widget : public QWidget
{


 Q_OBJECT
 
 private:
    DDS *SDR_ShellDDS; 
    
 public:
    Main_Widget(QWidget *parent = 0);    
        
 public slots:
    void finish();   
    void setDds( int );
       
 protected: 
    void closeEvent( QCloseEvent * );
    	
};
#endif


#include "DDS.h"

DDS::DDS( QWidget *parent) 
	: QWidget( parent)
{
 
    ddsFrame = new QFrame();
    ddsFrame->setGeometry( 400, 200, 450, 300 );
    ddsFrame->setMinimumWidth( 450 );
    ddsFrame->setMinimumHeight( 300 );
    ddsFrame->setWindowTitle("SDR-Shell : Frequency Control ");

    ddsFrame->show();
    
}

void DDS::closeEvent( QCloseEvent *e )
{
printf("closeEvent( QCloseEvent * )\n");
    e->accept();
    finish();
}

void DDS::finish()
{
printf("finish()\n");
//   exit( 0 );
}


#ifndef DDS_H
#define DDS_H

#include <QWidget>
#include <QFrame>
#include <QCloseEvent>
#include <QEvent>
#include <QAction>
#include <QObject>


class DDS : public QWidget
{
    Q_OBJECT
    

    private:
    
        QFrame *ddsFrame;
       
    public:
    
        DDS(QWidget *parent = 0);
   
    private slots:

        void finish();
        
    protected:
        void closeEvent( QCloseEvent * );

};
#endif

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[jacek]

The problem is that you never show that DDS widget, only ddsFrame, so DDS doesn't receive any close events.

[Mel Seyle]

Jacek,

Thanks for the reply. Yep, that was indeed the problem. I knew it had to be something fundamental. I'm still learning about C++ and Qt, and the forum has been a big help.

Thanks again for your response.


Mel Seyle