[Qt-interest] Retrieve a particular item from the QTreeView

[Sajjad]

Thanks Constantin,

The hint was quite a help i must say.

I did not get any warnings while the program was running.


Regards
Sajjad

On Fri, Mar 25, 2011 at 6:47 PM, Constantin Makshin <cmakshin at gmail.com>wrote:

> Here is a part of my application I'm currently working on:
>
> void TechniqueView::selectOperation (const QItemSelection& item)
> {
>    m_selectedOperation = item.isEmpty() ? 0 :
> m_model->operationIdAtRow(item.first().top());
>    emit selectionChanged();
> }
>
> TechniqueView::TechniqueView (...)
> {
>    ...
>    m_table = new QTableView(this);
>    m_model = new TechniqueModel(technique, m_table, false);
>    m_table->setModel(m_model);
>    m_table->setSelectionMode(QTableView::SingleSelection);
>    ...
>    connect(m_table->selectionModel(),
> SIGNAL(selectionChanged(QItemSelection, QItemSelection)),
> SLOT(selectOperation(QItemSelection)));
>    ...
> }
>
> Since I need to track only selected item(s), the second signal parameter is
> ignored.
> QItemSelection contains selection *ranges*, so even if the user selects all
> items in a view, this selection may be represented as one QItemSelection
> object. In my case only one item (table cell) can be selected at once, so
> the slot takes only the first item in the list.
>
> I admit this is somewhat simplified example of selectionChanged() signal
> usage, but unfortunately there's nothing [significantly] more complex I can
> demonstrate.
>
> On Friday 25 March 2011 19:52:14 Sajjad wrote:
> > Hello Constantin,
> >
> > Thanks for the hint.
> >
> > say for example i have to connect the click() signal to a slot. In my
> > previous post i specified how i did it.
> >
> > connect(object1, SIGNAL(clicked()),object2, use_declared_slot());
> >
> > As you have suggested, could you please any example hint either in the
> > QtDemos or in any other
> > free downloadable apps that have used selectionChanged(const
> > QItemSelection&,const QItemSelection&).
> >
> >
> > Thanks
> > Sajjad
> >
> > On Fri, Mar 25, 2011 at 5:02 PM, Constantin Makshin <cmakshin at gmail.com
> >wrote:
> >
> > > I don't know how exactly the pressed() signal of QAbstractItemView
> works, I
> > > used only clicked() signal of item views and signals emitted by
> selection
> > > models (particularly selectionChanged(QItemSelection, QItemSelection)).
> I
> > > think you should try them. And make sure you don't get any
> > > connection-related warning/error messages when the program is running.
> > >
> > > On Friday 25 March 2011 11:18:35 you wrote:
> > > > Hello Constantin,
> > > >
> > > > I gave the pressed signal a try and connected the signal to  a slot.
> > > > Initially the slot definition contains  a cout statement
> > > >
> > > >
> > > > to check if the pressed signal is actually captured. It is connected
> as
> > > > follows:
> > > >
> > > > ///////////////////////////////////////////////////////////////
> > > >
> > > >
> > >
> connect(m_h3dNodeTreeView,SIGNAL(pressed(QModelIndex)),this,SLOT(getH3DTreeItemData(QModelIndex)));
> > > >
> > > >
> > > > ///////////////////////////////////////////////////////////////
> > > >
> > > >
> > > > But withe the pressed signal i get not output. Any other hint?
> > > >
> > > >
> > > > Regards
> > > > Sajjad
> > > >
> > > > On Thu, Mar 24, 2011 at 12:24 AM, Constantin Makshin <
> cmakshin at gmail.com
> > > >wrote:
> > > >
> > > > > I can't say for sure what's the difference, but my guess is that
> > > pressed()
> > > > > is emitted when a mouse button is pressed and clicked() — when it's
> > > > > released.
> > > > >
> > > > > And you don't have to override mousePressEvent() as signals emitted
> by
> > > item
> > > > > views and selection models are more convenient, particularly
> because
> > > they
> > > > > provide index of the selected item.
> > > > >
> > > > > On Thursday 24 March 2011 01:08:39 Sajjad wrote:
> > > > > > Hello Constantin,
> > > > > >
> > > > > > Is there any difference between the signals pressed() and
> clicked().
> > > > > >
> > > > > > I have subclass the QTreeView as well. I was wondering if i
> should
> > > > > over-ride
> > > > > > the mousePressEvent() of QTreeView instead.
> > > > > >
> > > > > > Regards
> > > > > > Sajjad
> > > > > >
> > > > > > On Wed, Mar 23, 2011 at 10:44 PM, Constantin Makshin <
> > > cmakshin at gmail.com
> > > > > >wrote:
> > > > > >
> > > > > > > Take a look at QAbstractItemView::clicked(),
> > > > > QAbstractItemView::pressed()
> > > > > > > signals and selection model (returned by
> > > > > > > QAbstractItemView::selectionModel()) functions.
> > > > > > >
> > > > > > > On Thursday 24 March 2011 00:26:14 Sajjad wrote:
> > > > > > > > Hello forum,
> > > > > > > >
> > > > > > > > I have created a customized model by sub-classing the
> > > > > QAbstractItemModel
> > > > > > > > class and view the model in the QTreeView.
> > > > > > > >
> > > > > > > > Now when the user the click on a particular item in the tree
> view
> > > i
> > > > > want
> > > > > > > > retrieve the tree item from it.
> > > > > > > >
> > > > > > > > I have encapculated the QTreeView inside the customized
> widget.
> > > And
> > > > > then
> > > > > > > i
> > > > > > > > have over-ridden the mousePressEvent()
> > > > > > > >
> > > > > > > > {
> > > > > > > >      //I check for the left mouse press event and if not i
> return
> > > > > > > >
> > > > > > > >     //i need to look for the current clicked item - any way
> > > inside
> > > > > the
> > > > > > > > QTreeView to get it?
> > > > > > > > }
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Any hint to get it?
>
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