i need to use Alt+Ctrl+arrow keys combination

**prasad.ece2** · 4th September 2013, 07:02

i need to use Alt+Ctrl+arrow keys on custamised QGraphicsItem, i have tried below one, not working can any one suggest me better one

Qt Code:

Switch view

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)   //CBoxViewItem derived from Qgraphicsitem
{
    if(Qt::ControlModifier & Qt::AltModifier & f_event->modifiers())        //  i tried this also if( (Qt::ControlModifier && Qt::AltModifier) == f_event->modifiers()) 
    {
        qDebug()<<"ctrl+Alt";
 
        switch(f_event->key())
        {
            case Qt::Key_Up:
 
                break;
            case Qt::Key_Down:
 
                break;
            case Qt::Key_Left:
 
                break;
            case Qt::Key_Right:
 
                break;
    }
 }

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)   //CBoxViewItem derived from Qgraphicsitem
{
    if(Qt::ControlModifier & Qt::AltModifier & f_event->modifiers())        //  i tried this also if( (Qt::ControlModifier && Qt::AltModifier) == f_event->modifiers()) 
    {
        qDebug()<<"ctrl+Alt";

        switch(f_event->key())
        {
            case Qt::Key_Up:
               
                break;
            case Qt::Key_Down:
               
                break;
            case Qt::Key_Left:
                
                break;
            case Qt::Key_Right:
                
                break;
    }
 }

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**Santosh Reddy** · 4th September 2013, 07:22

This should help

Qt Code:

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class Widget : public QLabel
{
public:
    explicit Widget(QWidget * parent = 0)
        : QLabel(parent)
    {
        installEventFilter(this);
    }
protected:
    bool eventFilter(QObject *, QEvent * event)
    {
        if(event->KeyPress)
        {
            QKeyEvent * keyEvent = static_cast<QKeyEvent *>(event);
 
            if(keyEvent->type() == QEvent::KeyPress)
            {
                if(keyEvent->modifiers().testFlag(Qt::AltModifier)      &&
                   keyEvent->modifiers().testFlag(Qt::ControlModifier)   )
                {
                    switch(keyEvent->key())
                    {
                        case Qt::Key_Left:  setText("Alt + Ctrl + Key_Left");   break;
                        case Qt::Key_Up:    setText("Alt + Ctrl + Key_Up");     break;
                        case Qt::Key_Right: setText("Alt + Ctrl + Key_Right");  break;
                        case Qt::Key_Down:  setText("Alt + Ctrl + Key_Down");   break;
                        default:            setText("Use Only Arrow Keys");     break;
                    }
                }
                else
                    setText("Use Alt + Ctrl");
            }
        }
 
        return false;
    }
};
 
int main(int argc, char **argv)
{
    QApplication app(argc, argv);
 
    Widget widget;
    widget.show();
 
    return app.exec();
}

class Widget : public QLabel
{
public:
    explicit Widget(QWidget * parent = 0)
        : QLabel(parent)
    {
        installEventFilter(this);
    }
protected:
    bool eventFilter(QObject *, QEvent * event)
    {
        if(event->KeyPress)
        {
            QKeyEvent * keyEvent = static_cast<QKeyEvent *>(event);

            if(keyEvent->type() == QEvent::KeyPress)
            {
                if(keyEvent->modifiers().testFlag(Qt::AltModifier)      &&
                   keyEvent->modifiers().testFlag(Qt::ControlModifier)   )
                {
                    switch(keyEvent->key())
                    {
                        case Qt::Key_Left:  setText("Alt + Ctrl + Key_Left");   break;
                        case Qt::Key_Up:    setText("Alt + Ctrl + Key_Up");     break;
                        case Qt::Key_Right: setText("Alt + Ctrl + Key_Right");  break;
                        case Qt::Key_Down:  setText("Alt + Ctrl + Key_Down");   break;
                        default:            setText("Use Only Arrow Keys");     break;
                    }
                }
                else
                    setText("Use Alt + Ctrl");
            }
        }

        return false;
    }
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    Widget widget;
    widget.show();

    return app.exec();
}

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or simple

Qt Code:

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...
if((Qt::ControlModifier | Qt::AltModifier) & f_event->modifiers()) 
...

...
if((Qt::ControlModifier | Qt::AltModifier) & f_event->modifiers()) 
...

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**prasad.ece2** · 4th September 2013, 08:08

fine bro its working but the problem is as soon as i press Alt+Ctrl it going to default case (Use Only Arrow Keys), Alt+Ctrl+any arrow key it is going to default case only.

i have done as below

Qt Code:

Switch view

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
  if(f_event->KeyPress)
  {
     QKeyEvent * keyEvent = static_cast<QKeyEvent *>(f_event);
 
         if(f_event->type() == QEvent::KeyPress)
        {
            if(f_event->modifiers().testFlag(Qt::AltModifier) &&  f_event->modifiers().testFlag(Qt::ControlModifier) )
            {
                switch(f_event->key())
                {
                case Qt::Key_Left: 
                    qDebug()<<"Alt + Ctrl + Key_Left"; 
                    break;
                case Qt::Key_Up: 
                    qDebug()<<"Alt + Ctrl + Key_Up"; 
                    break;
                case Qt::Key_Right: 
                    qDebug()<<"Alt + Ctrl + Key_Right"; 
                    break;
                case Qt::Key_Down: 
                    qDebug()<<"Alt + Ctrl + Key_Down"; 
                    break;
                default: 
                    qDebug()<<"Use Only Arrow Keys"; 
                    break;
                }
           }
       }
   }

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
  if(f_event->KeyPress)
  {
     QKeyEvent * keyEvent = static_cast<QKeyEvent *>(f_event);
    
         if(f_event->type() == QEvent::KeyPress)
        {
            if(f_event->modifiers().testFlag(Qt::AltModifier) &&  f_event->modifiers().testFlag(Qt::ControlModifier) )
            {
                switch(f_event->key())
                {
                case Qt::Key_Left: 
                    qDebug()<<"Alt + Ctrl + Key_Left"; 
                    break;
                case Qt::Key_Up: 
                    qDebug()<<"Alt + Ctrl + Key_Up"; 
                    break;
                case Qt::Key_Right: 
                    qDebug()<<"Alt + Ctrl + Key_Right"; 
                    break;
                case Qt::Key_Down: 
                    qDebug()<<"Alt + Ctrl + Key_Down"; 
                    break;
                default: 
                    qDebug()<<"Use Only Arrow Keys"; 
                    break;
                }
           }
       }
   }

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**Santosh Reddy** · 4th September 2013, 08:41

Qt Code:

Switch view

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->type() == QEvent::KeyPress)
    {
        if(f_event->modifiers().testFlag(Qt::AltModifier) && f_event->modifiers().testFlag(Qt::ControlModifier) )
        {
            switch(f_event->key())
            {
                case Qt::Key_Left:
                    qDebug()<<"Alt + Ctrl + Key_Left";
                    break;
                case Qt::Key_Up:
                    qDebug()<<"Alt + Ctrl + Key_Up";
                    break;
                case Qt::Key_Right:
                    qDebug()<<"Alt + Ctrl + Key_Right";
                    break;
                case Qt::Key_Down:
                    qDebug()<<"Alt + Ctrl + Key_Down";
                    break;
                default:
                    qDebug()<<"Use Only Arrow Keys";
                    break;
            }
        }
    }
}

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->type() == QEvent::KeyPress)
    {
        if(f_event->modifiers().testFlag(Qt::AltModifier) && f_event->modifiers().testFlag(Qt::ControlModifier) )
        {
            switch(f_event->key())
            {
                case Qt::Key_Left:
                    qDebug()<<"Alt + Ctrl + Key_Left";
                    break;
                case Qt::Key_Up:
                    qDebug()<<"Alt + Ctrl + Key_Up";
                    break;
                case Qt::Key_Right:
                    qDebug()<<"Alt + Ctrl + Key_Right";
                    break;
                case Qt::Key_Down:
                    qDebug()<<"Alt + Ctrl + Key_Down";
                    break;
                default:
                    qDebug()<<"Use Only Arrow Keys";
                    break;
            }
        }
    }
}

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Please may attention while copying the code.

**prasad.ece2** · 4th September 2013, 10:05

yes, still i am facing same problem.. its going to default case always .

**Santosh Reddy** · 4th September 2013, 10:51

What is your platform and Qt Version, also can post a minimal code to reproduce the problem.

**prasad.ece2** · 4th September 2013, 11:15

windows 64-bit and Qt version is 4.8.5, i am using VS2010 by adding Qt plugin

Qt Code:

Switch view

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->KeyPress)
    {
        if(f_event->type() == QEvent::KeyPress)
        {
            if(f_event->modifiers().testFlag(Qt::AltModifier) && f_event->modifiers().testFlag(Qt::ControlModifier).)
            {
                switch(f_event->key())
                {
                    case Qt::Key_Left: 
                            qDebug()<<"Alt + Ctrl + Key_Left"; 
                            break;
                    case Qt::Key_Up: 
                            qDebug()<<"Alt + Ctrl + Key_Up"; 
                            break;
                    case Qt::Key_Right: 
                              qDebug()<<"Alt + Ctrl + Key_Right"; 
                               break;
                    case Qt::Key_Down:
                              qDebug()<<"Alt + Ctrl + Key_Down"; 
                              break;
                    default: 
                           qDebug()<<"Use Only Arrow Keys"; 
                           break;
                }
            }
            else
              qDebug()<<"Use Alt + Ctrl";
        }
    }
}

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->KeyPress)
    {
        if(f_event->type() == QEvent::KeyPress)
        {
            if(f_event->modifiers().testFlag(Qt::AltModifier) && f_event->modifiers().testFlag(Qt::ControlModifier).)
            {
                switch(f_event->key())
                {
                    case Qt::Key_Left: 
                            qDebug()<<"Alt + Ctrl + Key_Left"; 
                            break;
                    case Qt::Key_Up: 
                            qDebug()<<"Alt + Ctrl + Key_Up"; 
                            break;
                    case Qt::Key_Right: 
                              qDebug()<<"Alt + Ctrl + Key_Right"; 
                               break;
                    case Qt::Key_Down:
                              qDebug()<<"Alt + Ctrl + Key_Down"; 
                              break;
                    default: 
                           qDebug()<<"Use Only Arrow Keys"; 
                           break;
                }
            }
            else
              qDebug()<<"Use Alt + Ctrl";
        }
    }
}

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this is always going to default case only.

**Santosh Reddy** · 4th September 2013, 11:20

When the default case executes what is the value in f_event->key()?

**prasad.ece2** · 4th September 2013, 11:38

16777249

http://www.codeproject.com/Questions...inations-in-QT
he is saying that it is working in xp but not in Win7

**high_flyer** · 4th September 2013, 11:40

This code:

Qt Code:

Switch view

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->KeyPress)
    {...}

void CBoxViewItem::keyPressEvent(QKeyEvent* f_event)
{
    if(f_event->KeyPress)
    {...}

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Should not compile.
Are you sure this is the code you are compiling?

And please: use code tags when you post code its hard to read it that way.

**prasad.ece2** · 4th September 2013, 11:57

yes the same code i am compiling .

**high_flyer** · 4th September 2013, 11:58

Strange, since QKeyEvent doesn't have a member called 'KeyPress'.

**prasad.ece2** · 4th September 2013, 12:00

and sorry for inconvenience i am new to blog .

don't knw suddenly its working for for some time in between and stops working again .

**prasad.ece2** · 27th September 2013, 07:34

Finally came to know what is the problem... in the scene we have to set focus (item->setFocus(); QGraphicsScene::keyPressEvent(event); ) to the selected item then scene pass that event to that selected item...

- thank you Santosh Reddy .

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