[Qt-interest] Retrieve a particular item from the QTreeView
Sajjad
dosto.walla at gmail.com
Sat Mar 26 13:57:57 CET 2011
Hello Constantin,
I was sub-classing the QTreeView before , because i was not sure if i have
to do something special for the mouse press event. And probably this is why
i was not getting the selection by click event.
Now i removed the sub-classing and creating the object directly from the
QTreeView instead. Now i get the selection both with click and keyboard.
Do you think is it what i think - Sub classing the QTReeView shadows the
event capturing capability?
Regards
Sajjad
On Sat, Mar 26, 2011 at 1:22 PM, Constantin Makshin <cmakshin at gmail.com>wrote:
> I guess selection models work with clicked() or similar event, emitting
> signals when the user releases the mouse button (to allow selecting several
> items at once by using selection rectangle, for example).
>
> You may want to take a look at
>
>
> http://doc.qt.nokia.com/4.7/model-view-programming.html#using-drag-and-drop-with-item-views
>
> for information about drag&drop in item views.
>
> On Saturday 26 March 2011 15:02:12 Sajjad wrote:
> > Hello Constantin,
> >
> > Do you you if the selection model works only with the press event. I have
> to
> > enable the drag and drop event with the tree views .
> > But the item in the tree view only get selected with the keypress and not
> > with mouse press event.
> >
> > Any hint on this?
> >
> >
> > Regards
> > Sajjad
> >
> > On Fri, Mar 25, 2011 at 9:55 PM, Sajjad <dosto.walla at gmail.com> wrote:
> >
> > > 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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