[Qt-interest] FW: Scrolling Contents in QScrollArea

[Nikos Chantziaras]

Do not override scrollContentsBy().  You are not allowed to move the 
scrollbars in that function.  Also, you should not attempt to move the 
widgets manually.  QScrollArea will do that for you.  You only need to 
add the widgets you want into the QScrollArea.  Everything else happens 
automatically when the user moves the scrollbars.

If you want to scroll programatically, simply use the setValue() 
function of the scrollbars from wherever you want, *except* from 
scrollContentsBy() which, again, you should not be overriding for this 
purpose.


On 02/02/2011 11:00 AM, Sujan Dasmahapatra wrote:
> See I have many widgets that’s on the QScrollArea, those are already
> added to the QScrollArea. How can we move all of them together as we
> scroll.. That’s what I am looking for. Please help me. Thanks sujan
>
> Kind Regards,
>
> *Sujan Dasmahapatra
> *Project Leader, Aero Group
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> *From:*qt-interest-bounces+sdh=lmwindpower.com at qt.nokia.com
> [mailto:qt-interest-bounces+sdh=lmwindpower.com at qt.nokia.com] *On Behalf
> Of *Bo Thorsen
> *Sent:* Wednesday, February 02, 2011 1:30 PM
> *To:* qt-interest at qt.nokia.com
> *Subject:* Re: [Qt-interest] Scrolling Contents in QScrollArea
>
> Den 02-02-2011 08:01, Sujan Dasmahapatra skrev:
>
> Dear Friends
>
> I am using a QScrollArea which I can see some contents in it. By using
> the following code snippet I am able to see both the vertical and
> horizontal scrollbar. I am also implementing the virtual function
>
> //////////////////////////////////////////////////////////////////////////////////////////////////////////
>
>
> #include <QScrollArea>
>
> Class PageForGraph : public QScrollArea
>
> {
>
> Q_OBJECT
>
> Public:
>
> PageForGraph(QWidget *parent=0);
>
> virtual ~PageForGraph();
>
> };
>
> PageForGraph::PageForGraph(QWidget *parent)
>
> {
>
> verticalScrollBar()->setRange(0, 2 * desk->height());
>
> horizontalScrollBar()->setRange(0, 2 * desk->width());
>
> }
>
> void PageForGraph::scrollContentsBy(int dx, int dy)
>
> {
>
> widget()->move(widget()->x() + dx, widget()->y() + dy);
>
> const int x = horizontalScrollBar()->value() + dx;
>
> horizontalScrollBar()->setValue( x );
>
> const int y = verticalScrollBar()->value() + dy;
>
> verticalScrollBar()->setValue( y );
>
> update();
>
> }
>
> But when I moving the scrollbar my contents are not moving. Any help
> would be highly appreciated. Thanks sujan
>
>
> You are moving in the wrong direction here. Implement your graph widget
> to show off the graph and add it to a QScrollArea. And remember to set
> the size of the widget.
>
> If you want to implement a widget that has it's own scrollbars, then
> subclass QWidget, add two scrollbars yourself, and paint the widget
> according to the scrollbar positions.
>
> And please read the documentation for the class:
> http://doc.qt.nokia.com/4.7/qscrollarea.html.
>
> Bo Thorsen,
>
> Fionia Software.
>
>
>
> --
>
>
>
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>
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