this is the current application looks like this:
It has a Qlistwidget listWidget_links where each item has own itemwidget set (combobox, checkbox, button, ...) Now I came upon a problem that neither google or I can solve.
If the user presses the create button or any other item's itemwidget how do I let a method know the item the widget was pressed changed inside.
item_widget.comboBox_type.currentIndexChanged.connect(self.itemupdate_linktype)
item_widget.checkBox_hide.stateChanged.connect(self.itemupdate_hidden)
cbox = self.sender() # gives the widget that released the signal
cbox.parent() #I discovered by a lucky try, returns NodeLinkItemWidgetUI.Ui_Form object which is a item's itemwidget
Here is how items get created to in order to understand the program structure better:
def createNewLink(self, nodename, nodeclass):
item = QtWidgets.QListWidgetItem(self.listWidget_links)
item_widget = NodeLinkItemWidgetUI.Ui_Form(nodename, nodeclass)
item.nodename = nodename
item.nodeclass = nodeclass
item.setSizeHint(QtCore.QSize(130, 160))
self.listWidget_links.addItem(item)
self.listWidget_links.setItemWidget(item, item_widget)
Edit: solved setting the variable item_widget.item = item seems to work, but is there a more elegant way?
Related
My environment is Python 2.7, running on Windows 7.
I'm trying get a Tkinter Listbox to trigger a callback in response to the user changing the 'active' item (i.e. the item with focus). I'm using a binding to the <<ListboxSelect>> event to make this happen, and it's working -- sort of.
The callback itself is supposed to check what the new active item is, and carry out some processing accordingly. This logic operates the way I expect when I change the active item via the up/down arrow keys. But when I point & click on a new item instead, the code mistakenly identifies the prior active item as the current one.
Here's a stripped-down code sample that illustrates the behavior I'm getting:
import Tkinter as tk
#Root window
root = tk.Tk()
#Callback to show focus change
def updateDisplay(*args):
focusIndex = str(lb.index(tk.ACTIVE))
ctrlFI.set('Focus is at index '+focusIndex)
#Control variables
ctrlLB = tk.StringVar()
ctrlFI = tk.StringVar()
#Widgets
lb = tk.Listbox(root,
width=20, height=10,
relief=tk.FLAT,highlightthickness=0,
selectmode=tk.EXTENDED,
activestyle='dotbox',
listvariable=ctrlLB)
lbl = tk.Label(root,
justify=tk.LEFT, anchor=tk.W,
textvariable=ctrlFI)
lb.grid(row=0,column=0,sticky=tk.NW,padx=(5,0),pady=5)
lbl.grid(row=1,column=0,columnspan=2,sticky=tk.NW,padx=5,pady=5)
#Listbox binding to trigger callback
lb.bind('<<ListboxSelect>>',updateDisplay)
#Initializations to prep GUI
ctrlLB.set('Index0-entry Index1-entry Index2-entry Index3-entry Index4-entry')
ctrlFI.set('Ready')
#Begin app
tk.mainloop()
Here are the results when you use the arrow keys:
But here's what you get when you click with the mouse:
The information 'lags' one behind, showing the prior selection instead. (If you click the same item a second time, it 'catches up.')
So my questions are:
What is causing the discrepancy?
How do I fix it so the mouse click gives the right result?
The active item is not necessarily the same as the selected item. When you press the mouse down it changes the selected value but it does not change the active item. The active item only changes once you release the mouse button.
You should be able to see this by clicking and holding the mouse button over an item that is not currently selected. When you do, you'll see something like this:
In the above image, the active item is the one surrounded by a dotted outline. The selected item is in blue. When your code displays the 'focus', it's displaying the active element rather than the selected element.
If you want the selected item, you need to use curselection to get the index of the selected item. It returns a tuple, so in extended mode you need to get the first element that is returned (eg: lb.curselection()[0]). Be sure to handle the case where curselection returns an empty string.
I have a QTreeView in my widget. When an item is selected in the view, I have
a signal handler that updates a series of information widgets in a detail window
about the selected item. The user can then edit the item details and commit the
changes back to the model.
If the data in the details view has been edited when this selection change
happens, I present a confirmation dialog to the user before replacing the data
when a new item is selected. If the user cancels, I want to set the selection of
the tree back to what it was before.
I have my slot connected like so:
auto selection_model = treeview->selectionModel();
connect(
selection_model, &QItemSelectionModel::currentChanged,
this, &Editor::on_tree_selection_changed
)
Inside my slot, the code is structured as follows:
void on_tree_selection_changed(QModelIndex const& index, QModelIndex const& previous)
{
if(not confirm_editor_discard())
{
// user does not want to override current edits
log.trace("cancel item selection change");
using SF = QItemSelectionModel::SelectionFlags;
auto sm = treeview->selectionModel();
sm->setCurrentIndex(previous, SF::SelectCurrent | SF::Rows);
}
else
{
// user wants to discard, so update the details view.
log.trace("discard pending edits");
set_details_from_model(index);
}
}
However, the setting of the current index back to the previous does not seem to
affect the TreeView; it still displays the newly selected item as selected, and
the interface becomes non-coherent since the item displayed in the details is
not the one shown as selected in the tree.
The intended behaviour is to re-select the previously selected item, as if no
new selection was made at all.
Apparently the QTreeView ignores any updates from the selection model while the currentChanged slot is being called.
The solution here was to call the slot as a QueuedConnection, so the connect line would look like this:
connect(
selection_model, &QItemSelectionModel::currentChanged,
this, &Editor::on_tree_selection_changed,
Qt::QueuedConnection // <-- connection must be queued.
)
This will ensure that the change in selection of the selection model will not happen directly inside a slot call.
Here's my code:
class DefaultServiceClassWidget(ServiceClassWidget):
def __init__(self, mpet_widget, sc_data, idx):
super(DefaultServiceClassWidget, self).__init__(mpet_widget, sc_data, idx, DefaultServiceClassRow.number)
delete_default_sc_button = Button(mpet_widget.listFrame,justify=LEFT,text="x",fg="red",command= lambda: mpet_widget.delete_sc(self.idx))
delete_default_sc_button.grid(column=4,row=DefaultServiceClassRow.number)
self.select_default_class_label = Label(mpet_widget.listFrame,anchor=W,justify=LEFT,text="Select a Class")
self.select_default_class_label.grid(column=0,row=DefaultServiceClassRow.number)
options = ["All","CS Registration","GPRS Attach","PDP Activation","SMS","Reset","USSD","LTE"]
self.menu_pick_a_class = OptionMenu(mpet_widget.listFrame, sc_data.get_name(), *options, command=lambda event: sc_data.set_id())
self.menu_pick_a_class.grid(column=1,row=DefaultServiceClassRow.number)
self.row = DefaultServiceClassRow.number
DefaultServiceClassRow.number = DefaultServiceClassRow.number+2
def delete(self):
DefaultServiceClassRow.number = DefaultServiceClassRow.number - 2
default_list = (list(self.mpet_widget.listFrame.grid_slaves(row=self.row)) +
list(self.mpet_widget.listFrame.grid_slaves(row=self.row+1)))
for l in default_list:
l.grid_remove()
What happens is that there's a button connected to this function, every time the button is clicked, this function gets called and created a new grid on the GUI. What I want is that if for example "SMS" in optionmenu is selected, the next time this function gets called, "SMS" option will be grayed out (i.e. each option can be only selected once in the program)
I've tried updating status of the selected option by using status = "disabled" but it only works for the same grid, once a new grid(instance) is created, everything gets reset and all the options became available again :(
Also, in the same grid, if I disabled an option by selecting it and then changed to something else, the original selection is still grayed and cannot be selected again - I know why this happens but how do I fix it?
Sorry for the long question but I can't seem to find a solution online :(
Thank you in advance!
I have QTreeView with some items and search QLineEdit with connected slot on textEdited signal.
With this code:
QSortFilterProxyModel *proxyModel = new QSortFilterProxyModel(this);
proxyModel->setSourceModel(messagesModel);
proxyModel->setFilterFixedString(text);
ui.treeView->setModel(proxyModel);
text filtering is ok, but when I clicked on QTreeView QStandardItems checkboxes (after proxy model assigned to QTreeView), I have the program crashes in slot, that connected to this QTreeView original model (before proxy was assigned).
What is the right way to processing item checkbox clicks? Need I use new connect/slot to processing model changes, or I can use the same code for original model with some changes? I just need to hide filtered items in QTreeView. In QTreeWidget is hide() method, does QTreeView has something like this, or QSortFilterProxyModel - is what I need? Thx!
UPD crashed in slot, connected to treeView:
auto item = messagesModel->itemFromIndex(index); // item is NULL because proxyModel is set for TreeView now
if(item->whatsThis().isEmpty()) return; // error below
#ifndef QT_NO_WHATSTHIS
inline QString whatsThis() const {
return qvariant_cast<QString>(data(Qt::WhatsThisRole));
}
inline void setWhatsThis(const QString &whatsThis);
#endif
because I set proxyModel to treeView, but messagesModel have whatsThis...
I changed my code with that:
QStandardItem* item;
if(ui.leFilter->text().isEmpty())
item = messagesModel->itemFromIndex(index);
else
item = messagesModel->itemFromIndex(proxyModel->mapToSource(index));
if(item->whatsThis().isEmpty()) return;
and it works. Is that correct way? Proxy model is member of my UI class ... not local.
UPD how can I update source model when checkbox checked in proxyModel?
UPD 2 I have load "original" model for QtreeView and show it. When I edit text in QListEdit, I use proxyModel (code from 1st post). When text edited, I have check checkboxes in QtreeView (now proxyModel is active) and at this step all is ok. But when I do some changes in UI, in QTreeView set the original model and it has no changes that was made for proxyModel. How can I notify and update items in source Model with new data from proxyModel?
UPD3 Yes, source model is also modified ... I have just clear it)
I'm trying to do exclusive checkboxes as a QListView items. I'm using QStandardItemModel as a model with QStandardItem's.
I'm adding items to the list dynamically and set it checkable:
QStandardItem *item = new QStandardItem(treeView->model()->data(index).toString());
item->setCheckable(true);
m_categoriesModel->appendRow(item);
I tried connect all items to QSignalMapper but QStandardItem doesn't have checked(bool) signal (basically it does not have any).
Is there any way to solve the problem?
You can always make it in the way described below. Firstly connect the clicked signal of ListView to the slot which will handle your items click. Secondly inside of the slot you can get the item from QModelIndex and check the state of the item. Below is pseudo code:
For example, in constructor of ListView:
connect(this, SIGNAL(clicked(QModelIndex)), this, SLOT(_handleItemClicked(QModelIndex)));
Slot of ListView:
void ListView::_handleItemClicked(QModelIndex index)
{
QStandardItem* item = _model->itemFromIndex(index);
if( item->checkState() == Qt::Checked) qDebug() << "Checked!";
}
There actually is a class for exactly doing this: QButtonGroup
It's easy to use:
QButtonGroup *group = new QButtonGroup(this);
group->setExclusive(true);//now only one will be checked at a time
//add all buttons
group->addButton(this->ui->myFirstCheckbox);
//...
... at least for manually added buttons. Of course you can use it for the model too, but it would require you to find all the checkbox elements inside the view...