[Qt-interest] Tree Item view Highlighter

[André Somers]

Verstuurd vanaf mijn iPhone

Op 4 jan. 2011 om 19:51 heeft Sajjad <dosto.walla at gmail.com> het volgende geschreven:

> Hello 
> 
> emitting the dataChanged() is done only when we re-implement the setData() function. Should i over-ride data() or the setData() function?
No, emitting dataChanged is done when data in the model changes. That happens often when setData is called, but that is not the only thing that can trigger it. In this case, changing your regexp changes the data. So, you override data() as explained earlier, and you emit dataChanged when the regexp changes. 

André
> 
> 
> 
> Regards
> Sajjad
> 
> On Tue, Jan 4, 2011 at 6:53 PM, Scott Aron Bloom <Scott.Bloom at onshorecs.com> wrote:
> On Tue, Jan 4, 2011 at 10:21 AM, Andre Somers <andre at familiesomers.nl> wrote:
> 
> Op Di, 4 januari, 2011 9:21 am, schreef Sajjad:
> 
> 
> >>  Is there anything missing up there? I removed the other function that i
> >> over-rid mentioned in the previous post.
> >>
> >>  I am still not getting any effect. The textchanged() signal is
> >> connected
> >> to  the slot as before.
> >>
> >> Ah, of course... Sorry about that.
> >>
> >> First of all: are you getting an effect if you set a fixed regexp to
> >> begin
> >> with? If not, then something is wrong in the code above. Set a
> >> breakpoint
> >> where you return the color and see if you ever arrive there at all...
> >>
> >
> > I set the breakpoint at the slot
> >
> >   void H3DNodeListWidget::highlightRegExpChanged()
> >
> > {
> >
> >     QRegExp
> > regExp(m_nodeHighlightingEditor->text(),Qt::CaseInsensitive,QRegExp::FixedString);
> >
> >      m_highlightModel->setFilterRegExp(regExp);
> >
> > }
> >
> 
> I meant setting the breakpoint in the data() function.
> 
>  
> 
> The breakpoint  has been set there as well.
> 
> 
> > And i did not reach  the data() function while stepping into the code.
> 
> I can imagine it did not.
> 
> 
> >> However, I think the problem is, that you need to notify your view that
> >> the
> >> data has changed if your regexp changes. For testing, just emit reset(),
> >> but
> >> in your real implementation, you should probably be a bit nicer and emit
> >> dataChanged() with the right modelindexes.
> >>
> 
> i believ ethat the dataChanged() signal two model indexes as input parameter. I need to highlight only one tree item that maches the expression in the line edit. In that case how should i set the value for the signal that takes 2 input parameters. Should it be the same source index specified twice? I tried something as follows:
> 
>  
> 
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> 
>  
> 
> QVariant H3DHighlighterProxyModel::data(const QModelIndex &index, int role) const
> {
>     //get  the handle to  the underlyiing data
>     QModelIndex  sourceIndex = mapToSource(index);
>     if(!sourceIndex.isValid())
>     {
>         return QVariant();
>     }
>     if(role == Qt::BackgroundRole)
>     {
>         if(sourceModel()->data(sourceIndex).toString().contains(filterRegExp()))
>         {
>  
>             //the following statement gives error because the virtual function itself  
>  
>             //declared const 
>             emit dataChanged(sourceIndex,sourceIndex);
>             return Qt::cyan;
>         }
>         else
>         {
>             //return the default background color
>             //whatever may it be
>             return QVariant();
>         }
>     }
>     else
>     {
>         return sourceIndex.data(role);
>     }
> }
>  
> 
> ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> 
>  
> 
>  
> 
> And then if i have to set the connection as follows, i believe that it will not be valid:
> 
>  
> 
> connect(m_proxyMode,dataChanged(QModelIndex,QModelIndex),m_treeView,SLOT(update(QModelIndex))));
> 
>  
> 
> As you can see that the parameters are not matching. 
> 
>  
> 
> From all  the discussions you can imagine that i am having trouble to grasp the basic idea of model.view programming.
> 
> Could you provide some references where these issues are well discussed?
> 
>  
> 
>  
> 
> Regards
> 
> Sajjad
> 
> -----------------------
> 
>  
> 
>  
> 
> Yes, read the Qt documentation on model view programming…  and the signal/slot programming…
> 
>  
> 
> The dataChanged signal, allows you to send out a “square” of topLeft to bottomRight inclusive…  If topLeft == bottomRight, then only that cell is updated.
> 
>  
> 
> As to your update connection, you shouldn’t have to, all views are automatically connected to the dataChanged signal
> 
>  
> 
> Scott
> 
> 
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