Qt-interest Archive, June 2007
Re: QScrollArea - how to access events? - SOLVED
Message 1 in thread
I worked out a very simple solution to this problem - create a sub-class
of QScrollArea that redirects the events to the object contained in the
QScrollArea.
class NewScroll : public QScrollArea
{
void keyPressEvent(QKeyEvent *e)
{
QApplication::sendEvent(widget(),e);
}
void resizeEvent(QResizeEvent *e)
{
QScrollArea::resizeEvent(e);
QApplication::sendEvent(widget(),e);
}
void moveEvent(QMoveEvent *e)
{
QScrollArea::moveEvent(e);
QApplication::sendEvent(widget(),e);
}
void closeEvent(QCloseEvent *e)
{
QApplication::sendEvent(widget(),e);
QWidget::closeEvent(e);
}
public:
NewScroll() {};
};
I swallow all of the keystrokes in my contained class as PgUp PgDn rt&lft
arrow have specific functions in the contained class. The mouse scrolling still
works.
A bit kludgey, but it works!
DS
>----- Original Message ----
>From: David Scriven <davidwriter@xxxxxxxxx>
>To: qt-interest@xxxxxxxxxxxxx
>Sent: Thursday, May 24, 2007 11:09:59 AM
>Subject: QScrollArea - how to access events?
>
>I've created a data-image display system that is based on QGLWidget
>which pops up a stand-alone window containing the image. The size
>of the pseudo-image (i.e. derived from the data) is determined after
>the data is read in.
>
>class DataDisplay : public QGLWidget
>....
>void DataDisplay::Setup(QString FileName)
>{
> GetData(FileName);
> resize(nImageXdim,nImageYdim);
> show();
>}
>which works very nicely. I have a number of event handlers that
>deal with keyboard, mouse, move, resize and close events.
>
>I need to deal with the situation where either 1) the image size is
>greater than the screen size or 2) the image is zoomed to greater
>than the screen size.
>
>I tried embedding a QScrollArea in my code:
>
>void DataDisplay::Setup(QString FileName)
>{
> GetData(FileName);
>
> imageScroll = new QScrollArea();
> imageScroll->setWidget(this);
> imageScroll->setBackgroundRole(QPalette::Dark);
> resize(nImageXdim,nImageYdim);
> imageScroll->resize(nImageXdim+5,nImageYdim+5);
>// this last seems to be necessary so that the image frame matches
>// the size of the image and only adds a scroll bar when the image
>// has exceeds the screen size - is there a better way to do this?
>.........
>and that works, up to a point - but, of course, now all events such as
>keyboard, move, etc. are sent to the QScrollArea and not to my original
>class - so how to access them? There seems to be a viewportEvent in
>the base class, but I'm not sure how how to use this.
>
>DS
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