Qt - How to Transfer QListView Items to another QListView? - qt

I have a QLineEdit, 2 QPush buttons (Add & Remove Buttons) and a QListView. The Text which i am entering in the QLineEdit will gets added in the QListView when the add button is clicked. And if I'm selecting any one of the Item from the QListView and click the Remove Button the selected item will be removed. I finished these things and it works fine. Now i want to add a another QListView and if am Double clicking the QListView Items (QListView 1) the items should be transfered (items in the QListView 1 should be removed completely) to the new QListView (QListView 2) and vice versa. plz help me with your suggestions. Thanks in Advance.

Example.h
class Example : public QWidget
{
Q_OBJECT
public:
explicit Example(QWidget *parent = 0);
~Example();
private slots:
void on_listView_doubleClicked(const QModelIndex &index);
void on_listView_2_doubleClicked(const QModelIndex &index);
private:
QStandardItemModel *model; // This model is used when the add button is clicked.
QStandardItemModel *listViewModel;
};
Example.cpp
void Example::on_listView_doubleClicked(const QModelIndex &index)
{
QStandardItem *Item1;
Items1 = new QStandardItem();
Items1->setData(ui->listView->currentIndex().data(), Qt::DisplayRole );
Items1->setEditable( false );
listViewModel->appendRow( Items1 );
listViewModel->sort( 0, Qt::AscendingOrder );
ui->listView_2->setModel( listViewModel );
model->removeRow( ui->listView->currentIndex().row() );
}
void Example::on_listView_2_doubleClicked(const QModelIndex &index)
{
QStandardItem *Items2;
Items2 = new QStandardItem();
Items2->setData( ui->listView_2->currentIndex().data(), Qt::DisplayRole );
Items2->setEditable( false);
model->appendRow( Items2 );
model->sort( 0,Qt::AscendingOrder );
ui->listView->setModel( model );
model->removeRow( ui->listView_2->currentIndex().row() );
}

A more extensible way would be to create a custom model (possibly inheriting the QStringListModel if that suits your needs) and then implementing moveRows and/or the Drag&Drop facilities.

Related

Set QItemDelegate on a particular QTreeWidgetItem

Is it possible to set a QItemDelegate on a particular QTreeWidgetItem? I need to color some of the QTreeWidgetItems with a particular color.
I assume it is possible as we have QAbstractItemView::setItemDelegateForRow but I can't figure out how. I can't use QAbstractItemView::setItemDelegateForRow because I need to set a custom delegate on a child row inside the QTreeWidget.
Does anyone know a solution for that?
You can't use QTreeWidgetItem in delegate directly (probably you can store list of this items inside delegates but I think that it is not efficient), because delegates works with QModelIndex and data inside different roles. You can set data to Qt::UserRole+1 and access it inside delegate. For example:
QTreeWidgetItem *cities = new QTreeWidgetItem(ui->treeWidget);
//...
cities->setData(0,Qt::UserRole+1,"chosen one");
QTreeWidgetItem *osloItem = new QTreeWidgetItem(cities);
//...
QTreeWidgetItem *berlinItem = new QTreeWidgetItem(cities);
//...
berlinItem->setData(0,Qt::UserRole+1,"chosen one");
Inside delegate (just example):
void ItemDelegatePaint::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QString txt = index.model()->data( index, Qt::DisplayRole ).toString();
if( option.state & QStyle::State_Selected )
{
if(index.data(Qt::UserRole+1).toString() == "chosen one")
painter->fillRect( option.rect,Qt::green );
else
painter->fillRect( option.rect, option.palette.highlight() );
}else
if(option.state & QStyle::State_MouseOver)
{
if(index.data(Qt::UserRole+1).toString() == "chosen one")
painter->fillRect( option.rect,Qt::yellow );
else
painter->fillRect( option.rect, Qt::transparent );
}
else
{
QStyledItemDelegate::paint(painter,option,index);
}
}
You can access the QTreeWidget from you delegate's paint routine to check if a condition for painting the background is met
void custom_delegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
const QTreeWidget* tree_widget = qobject_cast<const QTreeWidget*>(qstyleoption_cast<const QStyleOptionViewItemV3*>(&option)->widget);
....
}
or you store something in the QModelIndex UserData as Chernobyl suggested. In that case I would however create an enum for flags (if this is applicable in your case):
enum custom_painter_flags{
paint_default = 0,
paint_background = 1
};
void somewhere_creating_the_items()
{
QTreeWidgetItem* newitem = new QTreeWidgetItem(...);
newitem->setData(0, Qt::UserRole, QVariant::fromValue<int>(custom_painter_flags::paint_background));
}
void custom_delegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
custom_painter_flags painter_flags = static_cast<painter>(index.data(Qt::UserRole).value<int>());
if(painter_flags & paint_background){
....
}
}
Unfortunately I have not much time right now so this is thrown together pretty quick. Feel free to edit if you find any errors.
You can use qss on the QTreeWidgetItem to change color or background color.
I have done it for a QTableWidget, You must check the value of all your QTreeWidgetItem and set a background color / color.
For example, for my QTableWidget i have done something like this in a loop :
if(good item):
MyQTableItem.setBackground(QtGui.QColor(255,255,255))

QListView and delegate display unintended item

I've a problem with my QListView, it paint an unintended item on the top left of the QListView :
http://s4.postimage.org/64orbk5kd/Screen_Shot_2013_02_14_at_20_23_14.png
I use a QStyledItemDelegate in my QListView :
m_stringList.push_back("FIRST");
m_stringList.push_back("SECOND");
m_stringList.push_back("THIRD");
m_model.setStringList(m_stringList);
ui->processesListView->setFlow(QListView::LeftToRight);
ui->processesListView->setModel(&m_model);
ui->processesListView->setItemDelegate(new ProcessItemDelegate(this, ui->processesListView));
The delegate (ProcessItemDelegate) paint method use a custom QWidget to display the information :
void ProcessItemDelegate::paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex &inIndex ) const
{
_listItem->setContent(_listView->model()->data(inIndex).toString());
painter->save();
painter->translate(option.rect.center());
_listItem->render(painter);
painter->restore();
}
The setContent method of the QWidget is very simple :
void ProcessItem::setContent(const QString &s)
{
ui->processId->setText(s);
}
I have another way to add a widget to some list using a QListWidget.
For example knowing that ui->historyView is a QListWidget element and HistoryElementView a subclass of QWidget.
void View::onHistoryChanged(const QList<HistoryElement> &history)
{
clearHistory();
foreach(HistoryElement elt, history)
{
HistoryElementView *historyViewElement = new HistoryElementView(elt.getDateTime("dd/MM/yyyy - hh:mm"), elt.getFilename());
QListWidgetItem *item = new QListWidgetItem();
ui->historyView->addItem(item);
ui->historyView->setItemWidget(item, historyViewElement);
}
}
void View::clearHistory()
{
QListWidgetItem *item;
while (ui->historyView->count() != 0)
{
item = ui->historyView->takeItem(0);
delete item;
}
}
You do not need to delete the widgets inside your QListWidgetItem, it will be handle by Qt.
Once your widgets are inside the list, you can retrieve them using :
// Using index
QListWidgetItem *item = ui->historyView->item(0);
HistoryElementView *elt = qobject_cast<HistoryElementView *>(ui->historyView->itemWidget(item));
// Using position
QListWidgetItem *item = ui->historyView->itemAt(pos);
HistoryElementView *historyElement = qobject_cast<HistoryElementView *>(ui->historyView->itemWidget(item));
Hope it helps.

QStyledItemDelegate - How does updateEditorGeometry works?

I'm using Qt 4.7.
I have a model that I display in a QTableView in two columns, and my goal is to provide inline editing of this model in my QTableView.
+-----------------+----------------+
| Axis position | Axis range |
+-----------------+----------------+
| Left | Fixed [0,1] |
| Left | Source: SRC1 |
| Right | Source: SRC2 |
| Left | Fixed [5,10] |
+-----------------+----------------+
The first column is editable by using a simple QComboxBox to switch between Right and Left, and it works quite well. The problem is with my second column, which is editable using a custom widget.
This widget is kind of simple, it describes a range. So there is a QComboBox to select the kind of range ("Fixed": the values are given by the user, "Source": the value are adjusted dynamically from the min/max of a source).
Here is the source code of my custom widget:
class RangeEditor : public QWidget
{
Q_OBJECT
public:
RangeEditor( ... );
~RangeEditor();
public:
CurveView::ConfigAxes::Range range () const;
QVariant minimum() const;
QVariant maximum() const;
DataModel* model () const;
void range ( CurveView::ConfigAxes::Range range );
void minimum( QVariant minimum );
void maximum( QVariant maximum );
void model ( DataModel* model );
public slots:
void rangeTypeChanged( int type );
private: // --- External editors
QComboBox* editRange_;
QSpinBox* editMinimum_;
QSpinBox* editMaximum_;
QComboBox* editModel_;
};
RangeEditor::RangeEditor( ... ) : QWidget(parent)
{
editRange_ = new QComboBox(this);
editMinimum_ = new QSpinBox (this);
editMaximum_ = new QSpinBox (this);
editModel_ = new QComboBox(this);
QHBoxLayout* layout = new QHBoxLayout();
setLayout(layout);
layout->addWidget( editRange_ );
layout->addWidget( editMinimum_ );
layout->addWidget( editMaximum_ );
layout->addWidget( editModel_ );
editRange_->addItem( "Fixed" );
editRange_->addItem( "Source" );
editModel_->setCurrentIndex(0);
editModel_->hide();
QObject::connect( editRange_, SIGNAL(currentIndexChanged(int)),
this, SLOT (rangeTypeChanged(int)) );
}
void RangeEditor::rangeTypeChanged( int type )
{
if ( type==CurveView::ConfigAxes::FIXED )
{
editMinimum_->show();
editMaximum_->show();
editModel_->hide();
}
else if ( type==CurveView::ConfigAxes::SOURCE )
{
editMinimum_->hide();
editMaximum_->hide();
editModel_->show();
}
}
Okay, so now, I created a QStyledItemDelegate to provide the view a custom editor for my columns. Here is how I did it:
class ConfigAxesDelegate : public QStyledItemDelegate
{
public:
ConfigAxesDelegate( ... );
~ConfigAxesDelegate();
public:
virtual QWidget* createEditor ( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const;
virtual void setEditorData ( QWidget* editor, const QModelIndex& index ) const;
virtual void setModelData ( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const;
virtual void updateEditorGeometry( QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index ) const;
};
QWidget* ConfigAxesDelegate::createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
if ( index.column()==0 ) // Position
{
PositionEditor* editor = new PositionEditor(parent);
return editor;
}
else if ( index.column()==1 ) // Range
{
RangeEditor* editor = new RangeEditor(parent);
return editor;
}
else
{
return QStyledItemDelegate::createEditor(parent,option,index);
}
}
void ConfigAxesDelegate::updateEditorGeometry( QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
// WHAT TO DO HERE?
editor->setGeometry( option.rect );
}
Basically, what I get is a single pixel height editor.
Here is a screenshot of the result:
I tried to changed updateEditorGeometry to the following:
void ConfigAxesDelegate::updateEditorGeometry( QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
QRect r = option.rect;
r.setSize( editor->sizeHint() );
editor->setGeometry( r );
}
Which seems to fix the size problem, but not the position:
I feel kind of lost since I don't know if the problem comes from my custom widget (not providing enough information for Qt to compute its position properly), or the view (maybe some margins that would crush the editor size), or the updateEditorGeometry() method.
Any help greatly appreciated, thanks for reading!
I would say setting editor's geometry by calling:
editor->setGeometry(rect);
should work correctly; What happens in your case is that your editor is built using QHBoxLayout which has default margins and spacing set. Default height of your tableview rows is less then editor's height and this makes your editor to resize; one pixel row on your screen shot would be: top margin + what's left from controls + bottom margin.
By enabling the vertical header for your tableview you would be able to resize row height to make your editor controls completely visible.
What you could possibly do:
1.Remove\decrease spacing and margins for the layout:
QHBoxLayout* layout = new QHBoxLayout();
layout->setSpacing(1);
layout->setMargin(1);
setLayout(layout);
in this case, updating editor's geometry this way:
QRect rect = option.rect;
QSize sizeHint = editor->sizeHint();
if (rect.width()<sizeHint.width()) rect.setWidth(sizeHint.width());
if (rect.height()<sizeHint.height()) rect.setHeight(sizeHint.height());
editor->setGeometry(rect);
or just
editor->setGeometry(rect);
should work fine for you
2.You can also consider using popup editors for your rows\cells values
3.Resize widget's row heights to fit cell editors.
hope this helps, regards

Determine if QTableView has an open editor

Is there any way to determine if a QTableView has an open editor in the current cell? I need to handle the following situation:
A user double-clicks a cell and edits the data, but leaves the cell in the "edit" state.
On another part of the UI, an action is taken that changes the selected row of the underlying model.
Back on my view, I want to determine if the newly selected row is the same as the open row. If not, I need to take an action. (Prompt the user? Commit automatically? Revert?)
I see how to get the current item, and can get the delegate on that item, but I don't see any isEditMode() property I was hoping to find.
Can someone point me in the right direction?
Just check whether the return value of
State QAbstractItemView::state () const
is
QTableView::EditingState
Connect to underlying model dataChanged signal
void QAbstractItemModel::dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight )
You can check if the cell where data has changed is the same than the currentIndex
QModelIndex QAbstractItemView::currentIndex () const
You cannot know if the current cell had an open editor straight, but can check if the view is in QAbstractItemView::EditingState
State QAbstractItemView::state () const
It should be enough to do what you want.
You can subclass QTableView in order to be able to access the state() function, which is unfortunately protected. However, I did not try that.
If you already have an QStyledItemDelegate subclass, you can use it to track whether an editor is currently open. However, you can't just use setEditorData/setModelData, because setModelData won't be called, when the user cancels editing. Instead, you can track the creation and destruction of the editor itself.
class MyItemDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
MyItemDelegate( QObject* parent = nullptr );
~MyItemDelegate();
QWidget* createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const;
void setEditorData( QWidget* editor, const QModelIndex& index ) const;
void setModelData( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const;
bool isEditorOpen() const { return *m_editorCount > 0; }
protected:
int* m_editorCount;
protected slots:
void onEditorDestroyed( QObject* obj );
};
Implementation:
MyItemDelegate::MyItemDelegate( QObject* parent ) :
QStyledItemDelegate( parent )
{
m_editorCount = new int;
*m_editorCount = 0;
}
MyItemDelegate::~MyItemDelegate()
{
delete m_editorCount;
}
QWidget* MyItemDelegate::createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
// create an editor, can be changed as needed
QWidget* editor = QStyledItemDelegate::createEditor( parent, option, index );
connect( editor, SIGNAL(destroyed(QObject*)), SLOT(onEditorDestroyed(QObject*)));
printf( "editor %p created\n", (void*) editor );
(*m_editorCount)++;
return editor;
}
void MyItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
...
}
void MyItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
...
}
void MyItemDelegate::onEditorDestroyed( QObject* obj )
{
printf( "editor %p destroyed\n", (void*) obj );
(*m_editorCount)--;
}
On some occasions, e.g. when moving to the next item in the tree using the cursor keys, Qt will create the new editor first and then destroy the old one. Hence, m_editorCount must be an integer instead of a bool.
Unfortunately, createEditor() is a const function. Therefore, you cannot create an int-member. Instead, create a pointer to an int and use that.
Subclass your delegate so that it includes an accessor that tells you when it's editing:
void MyDelegate::setEditorData ( QWidget * editor, const QModelIndex & index ) const {
// _isEditing will have to be mutable because this method is const
_isEditing = true;
QStyledItemDelegate::setEditorData(editor, index);
}
void MyDelegate::setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const {
QStyledItemDelegate::setModelData(editor, model, index);
_isEditing = false;
}
bool MyDelegate::isEditing() const { return _isEditing; }
Then you can just check the delegate to see what's going on. Alternatively and/or if you don't like the mutable, you can emit signals so you know what state the delegate is in.
If you know the index of the item being edited, you can call indexWidget() and attempt to cast it. If it's valid, you not only know you're editing, but you also have your editor widget handy.
EditWidget *editWidget = qobject_cast<EditWidget*>(tableView->indexWidget(tableView->currentIndex()));
if(editWidget)
{
//yep, ur editing bro
}
Here is an idea, its even helpful to get the edit/combo widget before the edit begins...
just emit a signal and consume it in the mainwindow... this is what I used one to get combo box in QTableWidget before editing...
first create a signal in ComoBoxItemDelegate...
signals:
void OnComboEdit(QComboBox* pCombo) const;
then emit the signal in the createEditor method...
QWidget* ComboBoxItemDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
// Create the combobox and populate it
QComboBox* cb = new QComboBox(parent);
emit OnComboEdit(cb);
return cb;
}
and in the MainWindow declare a function to receive the singal...
void MainWindow::OnComboEidt(QComboBox *pCB) const
{
qDebug() << "Combo Eidt Singal Received";
}
Then finally in the constructor of MainWindow connect it...
ComboBoxItemDelegate* cbid = new ComboBoxItemDelegate(ui->tableWidget);
connect(cbid, &ComboBoxItemDelegate::OnComboEdit, this, &MainWindow::OnComboEidt);
ui->tableWidget->setItemDelegateForColumn(0, cbid);

How to find item selected from customContextMenuRequested() on QTreeView item?

I have implemented contextual menus in QTreeView items with the following code
MyDerivedQTreeView->setModel(MyDerivedQAbstractItemModel);
MyDerivedQTreeView->setContextMenuPolicy(Qt::CustomContextMenu);
connect(MyDerivedQTreeView,
SIGNAL(customContextMenuRequested(const QPoint &)),
MyDerivedQAbstractItemModel(),
SLOT(contextualMenu(const QPoint &)));
void MyDerivedQAbstractItemModel::contextualMenu(const QPoint& point)
{
QMenu *menu = new QMenu;
menu->addAction(QString("Test Item"), this, SLOT(test_slot()));
menu->exec(MyDerivedQTreeView->mapToGlobal(point));
}
MyDerivedQAbstractItemModel::contextualMenu() gets called and I can see the contextual menu.
Problem is contextual menu should be visible only if user right-clicks on an item and it should be customized as per the item selected.
How do I get whether/which item is selected from QPoint information? I am on Qt 4.5.3.
Maybe you could use the indexAt() method of QTreeView to get the item where the click is made, before constructing your custom menu.
Maybe this code will help you:
==> dialog.h <==
QStandardItemModel *model;
QSortFilterProxyModel *proxyModel;
QTreeView *treeView;
==> dialog.cpp <==
void CImportTabWidget::createGUI() {
...
proxyModel = new QSortFilterProxyModel;
proxyModel->setDynamicSortFilter(true);
treeView = new QTreeView;
treeView->setEditTriggers(QAbstractItemView::NoEditTriggers);
treeView->setRootIsDecorated(false);
treeView->setAlternatingRowColors(true);
treeView->setModel(proxyModel);
model = new QStandardItemModel(0, 4);
model->setHeaderData(0, Qt::Horizontal, tr("Name"));
model->setHeaderData(1, Qt::Horizontal, tr("Comment"));
model->setHeaderData(2, Qt::Horizontal, tr("Size"));
model->setHeaderData(3, Qt::Horizontal, tr("Date"));
fillTreeViewData();
proxyModel->setSourceModel(model);
...
}
//////////////////////////////////////////////////////////////////////////
void CImportTabWidget::createMenus() {
treeView->setContextMenuPolicy(Qt::CustomContextMenu);
connect(treeView,
SIGNAL(customContextMenuRequested(const QPoint &)),
this,
SLOT(contextMenu(const QPoint &)));
}
//////////////////////////////////////////////////////////////////////////
void CImportTabWidget::contextMenu(const QPoint &widgetXY) {
Q_UNUSED(widgetXY);
QMenu menu(this);
/* Условия для меню */
deleteAct->setEnabled((!model->rowCount()) ? false : true );
deleteAllAct->setEnabled((!model->rowCount()) ? false : true );
/* Находим индекс */
QModelIndex index = treeView->currentIndex();
QString fileName = model->data(model->index(index.row(), 0)).toString();
if (!fileName.isEmpty()) {
importAct->setText(tr("Import %1").arg(fileName));
//deleteAct->setText(tr("Delete %1").arg(fileName));
}
/* Формируем меню */
menu.addAction(deleteAct);
menu.addAction(deleteAllAct);
menu.exec(QCursor::pos());
}
Good luck!
The QTreeWidget::currentItem() function returns the item that was right-clicked. It's not clear that it does so based on the description, but based on my usage of it, that is what it does.

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