Why can't I add or remove a QListWidgetItem? - c++

I have two ListWidget at my ui and I want to move one QListWidgetItem from availableMeasurementsListWidget to selectedMeasurementListWidget
But this won't work for me. Nothing adds into selectedMeasurementListWidget and the item does not removes from availableMeasurementsListWidget. Why?
That only who works is displaying the text of the qDebug() << item->text();
void ChartSettingsWindow::on_availableMeasurementsListWidget_doubleClicked(const QModelIndex &index)
{
Q_UNUSED(index);
QListWidgetItem *item = ui->availableMeasurementsListWidget->currentItem();
qDebug() << item->text();
ui->selectedMeasurementListWidget->addItem(item);
ui->availableMeasurementsListWidget->removeItemWidget(item);
}

Note that QListWidget:: removeItemWidget doesn't remove the QListWidgetItem from the QListWidget: it only...
Removes the widget set on the given item.
To remove an item (row) from the list entirely, either delete the item
or use takeItem().
So you probably want something like...
auto *available = ui->availableMeasurementsListWidget;
auto *selected = ui->selectedMeasurementListWidget;
auto *item = available->currentItem();
selected->addItem(available->takeItem(available->indexFromItem(item).row()));

Related

How to select item in QComboBox with QTreeView

I was trying to select item "leaf2" from QComboBox with QTreeView in the below code.
I just want to select items with no child from text by code. (if there is a child, it won't be selectable)
How can I select item or index with no child item?
Can anyone help me with this problem?
Thank you.
void Main::initView()
{
QStandardItemModel *model = new QStandardItemModel;
QStandardItem *root_item = model->invisibleRootItem();
// Build Model Items
QStandardItem *node_item = NULL;
node_item = new QStandardItem("Node");
node_item->setFlags(Qt::ItemIsEnabled);
root_item->appendRow(node_item);
QStandardItem *leaf_item = new QStandardItem("leaf1");
leaf_item ->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable);
node_item->appendRow(leaf_item );
leaf_item = new QStandardItem("leaf2");
leaf_item ->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable);
node_item->appendRow(leaf_item );
// Set Model to TreeViewComboBox
ui.cb_treevew->setModel(model);
ui.cb_treeview->setCurrentIndex(0); // "Node" is selected.
ui.cb_treeview->setCurrentIndex(1); // Nothing is selected.
ui.cb_treeview->setCurrentIndex(2); // Nothing is selected.
ui.cb_treeview->setCurrentIndex(3); // Nothing is selected.
}
Here is my code for CTreeViewComboBox.
CTreeViewComboBox::CTreeViewComboBox(QWidget *parent) : QComboBox(parent)
{
QTreeView* treeView = new QTreeView(this);
treeView->setEditTriggers(QTreeView::NoEditTriggers);
treeView->setSelectionBehavior(QTreeView::SelectRows);
treeView->setSelectionMode(QTreeView::SingleSelection);
treeView->setItemsExpandable(true);
treeView->header()->setVisible(false);
treeView->setWordWrap(true);
setView(treeView);
}
PS: I tried to select items as following, but not working. :(
ui.cb_treeview->treeView()->setCurrentIndex(getModelIndexFromText("leaf2"));
If the nodes with children will never have the same text with the nodes without children then the following method is appropriate.
QModelIndexList modelIndexes = model->match(
model->index(0, 0),
Qt::DisplayRole,
"leaf2",
-1,
Qt::MatchRecursive);
QModelIndex index = modelIndexes.first();
ui.cb_treeview.setRootModelIndex(index.parent());
ui.cb_treeview.setCurrentIndex(index.row());
On the other hand, if the nodes with children can have the same text as the nodes without children, you should use the following method.
QModelIndexList modelIndexes = model->match(
model->index(0, 0),
Qt::DisplayRole,
"leaf2",
-1,
Qt::MatchRecursive);
QModelIndexList::iterator tstIt = std::find_if(modelIndexes.begin(),
modelIndexes.end(),
[] (const QModelIndex & index) {
return !index.model()->hasChildren(index);
});
ui.cb_treeview.setRootModelIndex(tstIt->parent());
ui.cb_treeview.setCurrentIndex(tstIt->row());
In both cases I am assuming that nodes without children always have different texts. If nodes without children match the name, choose one of them.

Qt5 : Get value of item clicked in a listview

I'm making a Qt5.7 application where I am populating a QListView after reading stuff from a file. Here's the exact code of it.
QStringListModel *model;
model = new QStringListModel(this);
model->setStringList(stringList); //stringList has a list of strings
ui->listView->setModel(model);
ui->listView->setEditTriggers(QAbstractItemView::NoEditTriggers); //To disable editing
Now this displays the list just fine in a QListView that I have set up. What I need to do now is to get the string that has been double clicked and use that value elsewhere. How do I achieve that?
What I tried doing was to attach a listener to the QListView this way
... // the rest of the code
connect(ui->listView, SIGNAL(doubleClicked(QModelIndex)), this, SLOT(fetch()));
...
And then I have the function fetch
void Window::fetch () {
qDebug() << "Something was clicked!";
QObject *s = sender();
qDebug() << s->objectName();
}
However the objectName() function returns "listView" and not the listView item or the index.
The signal already provides you with a QModelIndex which was clicked.
So you should change your slot to this:
void Window::fetch (QModelIndex index)
{
....
QModelIndex has now a column and a row property. Because a list has no columns you are interessted in the row. This is the index of the item clicked.
//get model and cast to QStringListModel
QStringListModel* listModel= qobject_cast<QStringListModel*>(ui->listView->model());
//get value at row()
QString value = listModel->stringList().at(index.row());
You should add the index as parameter of your slot. You can use that index to access the list
Your code should be some thing like this.
void Window::fetch (QModelIndex index) {
/* Do some thing you want to do*/
}

C++ QListView with icons And Signals on items clicked

I have a QListview where I have set a model. The model contains the QList. Now I want to get the contents of QListview on clicking the item. But I don't know how to do this? Through some tutorials I followed I am able to get two items appear in the QListview as follows. But I dont know how to make it work?? Please anyone help. The code which I am working as follows.
listviewmodel =new QListView;
listviewmodel->setModel( createModel() );
listviewmodel->setViewMode(QListView::IconMode);
listviewmodel->setIconSize(QSize(size().width()/8, size().height()/8));
connect(listviewmodel,SIGNAL(clicked(const QModelIndex)),this,SLOT(ItemClicked(QModelIndex)));
QAbstractItemModel *MainWindow::createModel()
{
QStandardItemModel *model = new QStandardItemModel();
QList<QStandardItem *> listItem;
QStandardItem *item2 = new QStandardItem();
item2->setIcon(QIcon(QPixmap::fromImage(qimages2)));
listItem << item2;
QStandardItem *item1 = new QStandardItem();
item1->setIcon(QIcon(QPixmap::fromImage(qimages1)));
listItem << item1;
model->appendColumn(listItem);
return model;
}
void MainWindow::ItemClicked (QModelIndex index )
{
textEdit->setText(index.data().toString());
}
I checked your code in QtCreator and it works as you described. So what is the problem? Are you getting some errors? Maybe did you not put declaration of ItemClicked(QModelIndex) below the public slots:? Are you sure that connect returns true? Try to check it:
bool success = connect(listviewmodel,SIGNAL(clicked(const QModelIndex)),this,SLOT(ItemClicked(QModelIndex)));
Q_ASSERT(success);
EDIT: If you want to display only icons at QListView and get some text informations after clicking on specified item, you can do it in the following way:
item2->setIcon(QIcon(QPixmap::fromImage(qimages2)));
item2->setData("informations about item2", Qt::UserRole);
(...)
void MainWindow::ItemClicked (QModelIndex index )
{
QString data = index.data(Qt::UserRole).value<QString>();
ui->textEdit->setText(data);
}

Changing data in a QTableView depending on the selection of a QComboBox

I have a QComboBox in one of the columns of a QTableView. How can I change the other columns depending on what I selected in the ComboBox? I am using the QComboBox as a delegate.
There are at least 2 approaches.
Use natural for Qt's model itemChanged signal.
emit signal from your delegate and catch it inside your main window.
If your delegate is standard which means that inside setModelData() method you have something like:
QComboBox *line = static_cast<QComboBox*>(editor);
QString data = line->currentText();
//...
model->setData(index, data);
then I think you should use just natural way. For example:
connect(model,&QStandardItemModel::itemChanged,[=](QStandardItem * item) {
if(item->column() == NEEDED_COLUMN)
{
//you found, just get data and use it as you want
qDebug() << item->text();
}
});
I used here C++11 (CONFIG += c++11 to .pro file) and new syntax of signals and slots, but of course you can use old syntax if you want.
I already reproduced your code(delegate with combobox) and my solution works if I select something in combobox and confirm that by enter clicking for example. But if you want to get solution where data will be changed automatically, when you select another item in combobox(without pressing enter) then see next case:
Create special signal onside delegate:
signals:
void boxDataChanged(const QString & str);
Create connection inside createEditor() method:
QWidget *ItemDelegate::createEditor(QWidget *parent,
const QStyleOptionViewItem &option,
const QModelIndex &index) const
{
QComboBox *editor = new QComboBox(parent);
connect(editor,SIGNAL(currentIndexChanged(QString)),this,SIGNAL(boxDataChanged(QString)));
return editor;
}
And use it!
ItemDelegate *del = new ItemDelegate;
ui->tableView->setItemDelegate( del);
ui->tableView->setModel(model);
connect(del,&ItemDelegate::boxDataChanged,[=](const QString & str) {
//you found, just get data and use it as you want
qDebug() << str;
});

Getting variable from widget in a QListWidget

I have a custom QWidget class called VideoWidget. Its source file looks something like this:
VideoWidget::VideoWidget(QWidget *parent, string test) :
QWidget(parent)
{
pathname=test;
QLabel *label= new QLabel(pathname.c_str(), this);
//...
}
string VideoWidget::getFilePath(){
return pathname;
}
In my MainWindow class I add the VideoWidget to a QListWidget through looping through a xml file and getting the string argument from that file like this:
QDomNode node = rootXML.firstChild();
while( !node.isNull() )
{
if( node.isElement() )
{
QDomElement element = node.toElement();
VideoWidget* mytest = new VideoWidget(this, element.attribute( "Pathname", "not set").toStdString());
QListWidgetItem* item = new QListWidgetItem;
item->setSizeHint(QSize(150,100));
ui->myList->addItem(item);
ui->myList->setItemWidget(item,mytest);
}
node = node.nextSibling();
}
This correctly fills my QListWidget with the VideoWidget where all the labels have a different value.
Now I'd like to get the pathname variable everytime I doubleclick on a item in the QListWidget like this:
connect(ui->myList,SIGNAL(doubleClicked(QModelIndex)),this,SLOT(playClip(QModelIndex)));
void MainWindow::playClip(QModelIndex index){
QListWidgetItem* item = ui->myList->itemAt(0,index.row());
VideoWidget* widget = dynamic_cast<VideoWidget*>(ui->myList->itemWidget(item));
cout << widget->getFilePath() << endl;
}
My problem is that widget->getFilePath() always returns the same value for every clicked widget. It is the value of the first time I set pathname=test;. What am I missing here?
This is probably mistake:
QListWidgetItem* item = ui->myList->itemAt(0,index.row());
Method "itemAt" takes x and y coordinates, not indexes. Use "takeItem" instead.
Next thing I want to say is that this part:
ui->myList->itemWidget(item)
is useless. You can convert "item" directly.
And last - use qobject_cast since you use Qt. And never use dynamic_case (especially when you anyway do not check result against NULL).