I have an user interface that uses a TableView. It has 3 columns. The last column has a comboBox. All the data is inserted with the delegate. The problem is I can not find a method to send a signal to a public slot of the user interface class when the combobox index is changed.
With the delegate I already know the current index. Do someone know a method to send this index to the ui? I do not think the only possible solution is with signals and slots. Is a direct solution to extract this data?
EDIT
What I understand it is I have to do something like this:
void Delegate :: setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
if(index.column() == COL_Coordonate) // test if we are at the last column
{
QComboBox *comboBox = static_cast<QComboBox*>(editor);
model -> setData(index, comboBox -> currentIndex(), Qt::EditRole);
emit dataChanged(comboBox -> currentIndex(),comboBox -> currentIndex()); // something like this you have in mind?
}
}
And how can I receive that index in the user interface? I create my model in there something like:
QStandardItemModel *model;
Delegate *mydelegate;
And use them like:
mydelegate = new Delegate(this);
model = new QStandardItemModel(0, 3, this); // I add rows dynamically
ui -> tableView -> setModel(model);
ui -> tableView -> setItemDelegate (mydelegate);
I add data with the delegate when I press a button. Do I need do trigger a slot from this interface? If so someone can please provide a sample of code about how do I do this?
You have a QComboBox instance. You can connect to its signals. What do you not know? In any case, you should not be connecting to the delegate: it is an implementation detail of the view. You should interface with the model, not with the view. Connect to the model's dataChanged signal!
Related
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.
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...
My situation looks like this: I have QTableView and LineEdit. I'd like to show data which contains value in LineEdit in real time. I guess I should use QSortProxyFilterModel, but I don't know how to do that. I wrote this:
void MainWindow::on_lineFind_textEdited(const QString &arg1)
{
QSortFilterProxyModel proxy;
proxy.setSourceModel(ui->tableView->model());
proxy.setFilterRegExp(arg1);
QModelIndex index=proxy.mapToSource(proxy.index(0,0));
if(index.isValid())
{
ui->tableView->selectionModel()->select(index,QItemSelectionModel::Select | QItemSelectionModel::Rows);
ui->tableView->scrollTo(index,QAbstractItemView::EnsureVisible);
}
}
But it doesn't work (no change visible). Example how it should work: Clementine Player playlist.
You create QSortFilterProxyModel and destroy it immediately in your function. It's incorrect use. You need to create one object of QSortFilterProxyModel (maybe using new), then call QTableView::setModel for attaching proxy model to your view. After that changes will take effect.
In the initialization:
ui->setupUi(this);
my_model = new QStandardItemModel(); // or any other model class
proxy_model = new QSortFilterProxyModel();
ui->table_view->setModel(proxy_model);
proxy_model->setSourceModel(my_model);
In textEdited slot:
proxy_model->setFilterRegExp(arg1);
I'm making a simple file explorer and I ran into some problems with Qt. I want to show the user a tree view of files on his computer, but I also want to be able to select multiple files/directories and do something with them later on (by selecting checkboxes or multiple select using ctrl+left click or shift+left click). I've placed the QTreeView element and set up a model to it (QFileSystemModel). It gives me a good tree view, but I can't modify the headers (column names) or add my own column with checkbox in every row (for example). Qt is new to me, I've searched for few good hours for some tips/solutions, but nothing is working with QFileSystemModel. Is there anything I can do to get this working?
The code is short and simple:
QString lPath = "C:/";
QString rPath = "C:/";
leftTree_model = new QFileSystemModel(this);
rightTree_model = new QFileSystemModel(this);
leftTree_model->setRootPath(lPath);
rightTree_model->setRootPath(rPath);
//i have actually 2 tree views that work the same
ui->leftTree->setModel(leftTree_model); //ui->leftTree is the first tree view
ui->rightTree->setModel(rightTree_model); //the second
Use something of the following:
CheckStateRole to add checkboxes to your model. To do this, you inherit your custom item model (which you're going to use) from the QFileSystemModel, and reimplement the data() method, where you return bool values for CheckStateRole. You will also need the QAbstractItemModel::setData method to handle changes. You can also check the docs for QAbstractItemModel to see how to change header texts (headerData())
Change the selection mode of your view to allow multiple selections
EDIT:
here's a sample code to inherit from the model
class MyFancyModel : public QFileSystemModel
{
public:
MyFancyModel(QObject* pParent = NULL) : QFileSystemModel(pParent)
{
}
QVariant data(const QModelIndex & index, int role = Qt::DisplayRole ) const
{
if (role == Qt::CheckStateRole)
{
// stub value is true
return true; // here you will return real values
// depending on which item is currently checked
}
return QFileSystemModel::data(index, role);
}
};