[Qt-interest] Trying to create custom Qt Designer plugin for real-time data

[Friedemann Kleint]

Hi,

hoping I understand the problem correctly, I would suggest:

1) Declare the 'channel' property in the custom widget header:
Q_PROPERTY(QString channel READ channel WRITE setChannel DESIGNABLE true)
(see http://doc.trolltech.com/4.6/qobject.html#Q_PROPERTY ) and implement the 
getters/setters. The property will then appear in the property editor of Qt 
Designer, enabling the user to enter a channel name. 

Alternatively, if you want to present a combo box listing the available   
channels in a dialog box, you could implement a QDesignerTaskMenuExtension 
instance for your custom widget  (see 
http://doc.trolltech.com/4.6/qdesignertaskmenuextension.html), It would then 
set the channel chosen using QDesignerFormWindowCursorInterface::setProperty 
(see  http://doc.trolltech.com/4.6/qdesignerformwindowcursorinterface.html).

2) I assume it is desirable that the data retrieval is not triggered by the 
widgets on the form editor while editing. To achieve that, you could for 
example add a hidden property
Q_PROPERTY(bool dataRetrievalActive READ  isDataRetrievalActive WRITE 
setDataRetrievalActive  DESIGNABLE false)

defaulting to true. You would then set it to false if the widget is located on 
a form in the implementation of 
QDesignerCustomWidgetInterface::createWidget(). To find out if the widget is on 
a form, QDesignerFormWindowInterface::findFormWindow() can be used on the 
parent parameter:

MyCustomWidgetInterface::createWidget(QWidget *parent)
{
    MyWidget *mw = new MyWidget(parent);
    if (QDesignerFormWindowInterface::findFormWindow(parent))
        mw->setDataRetrievalActive(false);
...

Data retrieval would then start as soon as the user does a preview of the 
form.

I hope this helps,

Regards,
Friedemann
-- 
Friedemann Kleint
Nokia, Qt Development Frameworks