Qt 4.8: QListWidget Class Reference

Qt Reference Documentation

# QListWidget Class Reference

The QListWidget class provides an item-based list widget. More...

     #include <QListWidget>

Inherits: QListView.

- List of all members, including inherited members
- Obsolete members

## Properties

- count : const int
- currentRow : int
- sortingEnabled : bool

- 13 properties inherited from QListView
- 16 properties inherited from QAbstractItemView
- 2 properties inherited from QAbstractScrollArea
- 6 properties inherited from QFrame
- 58 properties inherited from QWidget
- 1 property inherited from QObject

## Public Functions

| QListWidget ( QWidget * parent = 0 )
| ~QListWidget ()
void | addItem ( const QString & label )
void | addItem ( QListWidgetItem * item )
void | addItems ( const QStringList & labels )
void | closePersistentEditor ( QListWidgetItem * item )
int | count () const
QListWidgetItem * | currentItem () const
int | currentRow () const
void | editItem ( QListWidgetItem * item )
QList<QListWidgetItem *> | findItems ( const QString & text, Qt::MatchFlags flags ) const
void | insertItem ( int row, QListWidgetItem * item )
void | insertItem ( int row, const QString & label )
void | insertItems ( int row, const QStringList & labels )
bool | isSortingEnabled () const
QListWidgetItem * | item ( int row ) const
QListWidgetItem * | itemAt ( const QPoint & p ) const
QListWidgetItem * | itemAt ( int x, int y ) const
QWidget * | itemWidget ( QListWidgetItem * item ) const
void | openPersistentEditor ( QListWidgetItem * item )
void | removeItemWidget ( QListWidgetItem * item )
int | row ( const QListWidgetItem * item ) const
QList<QListWidgetItem *> | selectedItems () const
void | setCurrentItem ( QListWidgetItem * item )
void | setCurrentItem ( QListWidgetItem * item, QItemSelectionModel::SelectionFlags command )
void | setCurrentRow ( int row )
void | setCurrentRow ( int row, QItemSelectionModel::SelectionFlags command )
void | setItemWidget ( QListWidgetItem * item, QWidget * widget )
void | setSortingEnabled ( bool enable )
void | sortItems ( Qt::SortOrder order = Qt::AscendingOrder )
QListWidgetItem * | takeItem ( int row )
QRect | visualItemRect ( const QListWidgetItem * item ) const

## Reimplemented Public Functions

virtual void | dropEvent ( QDropEvent * event )

- 32 public functions inherited from QListView
- 57 public functions inherited from QAbstractItemView
- 17 public functions inherited from QAbstractScrollArea
- 14 public functions inherited from QFrame
- 221 public functions inherited from QWidget
- 29 public functions inherited from QObject
- 13 public functions inherited from QPaintDevice

## Public Slots

void | clear ()
void | scrollToItem ( const QListWidgetItem * item, QAbstractItemView::ScrollHint hint = EnsureVisible )

- 9 public slots inherited from QAbstractItemView
- 19 public slots inherited from QWidget
- 1 public slot inherited from QObject

## Signals

void | currentItemChanged ( QListWidgetItem * current, QListWidgetItem * previous )
void | currentRowChanged ( int currentRow )
void | currentTextChanged ( const QString & currentText )
void | itemActivated ( QListWidgetItem * item )
void | itemChanged ( QListWidgetItem * item )
void | itemClicked ( QListWidgetItem * item )
void | itemDoubleClicked ( QListWidgetItem * item )
void | itemEntered ( QListWidgetItem * item )
void | itemPressed ( QListWidgetItem * item )
void | itemSelectionChanged ()

- 1 signal inherited from QListView
- 6 signals inherited from QAbstractItemView
- 1 signal inherited from QWidget
- 1 signal inherited from QObject

## Protected Functions

virtual bool | dropMimeData ( int index, const QMimeData * data, Qt::DropAction action )
QModelIndex | indexFromItem ( QListWidgetItem * item ) const
QListWidgetItem * | itemFromIndex ( const QModelIndex & index ) const
QList<QListWidgetItem *> | items ( const QMimeData * data ) const
virtual QMimeData * | mimeData ( const QList<QListWidgetItem *> items ) const
virtual QStringList | mimeTypes () const
virtual Qt::DropActions | supportedDropActions () const

## Reimplemented Protected Functions

virtual bool | event ( QEvent * e )

- 26 protected functions inherited from QListView
- 36 protected functions inherited from QAbstractItemView
- 18 protected functions inherited from QAbstractScrollArea
- 3 protected functions inherited from QFrame
- 37 protected functions inherited from QWidget
- 8 protected functions inherited from QObject
- 1 protected function inherited from QPaintDevice

### Additional Inherited Members

- 4 static public members inherited from QWidget
- 7 static public members inherited from QObject
- 9 protected slots inherited from QAbstractItemView
- 1 protected slot inherited from QAbstractScrollArea
- 1 protected slot inherited from QWidget

## Detailed Description

The QListWidget class provides an item-based list widget.

QListWidget is a convenience class that provides a list view similar to the one supplied by QListView, but with a classic item-based interface for adding and removing items. QListWidget uses an internal model to manage each QListWidgetItem in the list.

For a more flexible list view widget, use the QListView class with a standard model.

List widgets are constructed in the same way as other widgets:

         QListWidget *listWidget = new QListWidget(this);

The selectionMode() of a list widget determines how many of the items in the list can be selected at the same time, and whether complex selections of items can be created. This can be set with the setSelectionMode() function.

There are two ways to add items to the list: they can be constructed with the list widget as their parent widget, or they can be constructed with no parent widget and added to the list later. If a list widget already exists when the items are constructed, the first method is easier to use:

         new QListWidgetItem(tr("Oak"), listWidget);
         new QListWidgetItem(tr("Fir"), listWidget);
         new QListWidgetItem(tr("Pine"), listWidget);

If you need to insert a new item into the list at a particular position, then it should be constructed without a parent widget. The insertItem() function should then be used to place it within the list. The list widget will take ownership of the item.

         QListWidgetItem *newItem = new QListWidgetItem;
         newItem->setText(itemText);
         listWidget->insertItem(row, newItem);

For multiple items, insertItems() can be used instead. The number of items in the list is found with the count() function. To remove items from the list, use takeItem().

The current item in the list can be found with currentItem(), and changed with setCurrentItem(). The user can also change the current item by navigating with the keyboard or clicking on a different item. When the current item changes, the currentItemChanged() signal is emitted with the new current item and the item that was previously current.

A Windows XP style list widget. | A Macintosh style list widget. | A Plastique style list widget.

See also QListWidgetItem, QListView, QTreeView, Model/View Programming, and Config Dialog Example.

## Property Documentation

### count : const int

This property holds the number of items in the list including any hidden items.

Access functions:

int | count () const

### currentRow : int

This property holds the row of the current item.

Depending on the current selection mode, the row may also be selected.

Access functions:

int | currentRow () const
void | setCurrentRow ( int row )
void | setCurrentRow ( int row, QItemSelectionModel::SelectionFlags command )

Notifier signal:

void | currentRowChanged ( int currentRow )

### sortingEnabled : bool

This property holds whether sorting is enabled.

If this property is true, sorting is enabled for the list; if the property is false, sorting is not enabled.

The default value is false.

This property was introduced in Qt 4.2.

Access functions:

bool | isSortingEnabled () const
void | setSortingEnabled ( bool enable )

## Member Function Documentation

### QListWidget::QListWidget ( QWidget * parent = 0 )

Constructs an empty QListWidget with the given parent.

### QListWidget::~QListWidget ()

Destroys the list widget and all its items.

### void QListWidget::addItem ( const QString & label )

Inserts an item with the text label at the end of the list widget.

### void QListWidget::addItem ( QListWidgetItem * item )

Inserts the item at the end of the list widget.

Warning: A QListWidgetItem can only be added to a QListWidget once. Adding the same QListWidgetItem multiple times to a QListWidget will result in undefined behavior.

See also insertItem().

### void QListWidget::addItems ( const QStringList & labels )

Inserts items with the text labels at the end of the list widget.

See also insertItems().

### void QListWidget::clear ()`[slot]`

Removes all items and selections in the view.

Warning: All items will be permanently deleted.

### void QListWidget::closePersistentEditor ( QListWidgetItem * item )

Closes the persistent editor for the given item.

See also openPersistentEditor().

### QListWidgetItem * QListWidget::currentItem () const

Returns the current item.

See also setCurrentItem().

### void QListWidget::currentItemChanged ( QListWidgetItem * current, QListWidgetItem * previous )`[signal]`

This signal is emitted whenever the current item changes.

previous is the item that previously had the focus; current is the new current item.

### void QListWidget::currentRowChanged ( int currentRow )`[signal]`

This signal is emitted whenever the current item changes.

currentRow is the row of the current item. If there is no current item, the currentRow is -1.

### void QListWidget::currentTextChanged ( const QString & currentText )`[signal]`

This signal is emitted whenever the current item changes.

currentText is the text data in the current item. If there is no current item, the currentText is invalid.

### void QListWidget::dropEvent ( QDropEvent * event )`[virtual]`

Reimplemented from QWidget::dropEvent().

### bool QListWidget::dropMimeData ( int index, const QMimeData * data, Qt::DropAction action )`[virtual protected]`

Handles data supplied by an external drag and drop operation that ended with the given action in the given index. Returns true if data and action can be handled by the model; otherwise returns false.

See also supportedDropActions().

### void QListWidget::editItem ( QListWidgetItem * item )

Starts editing the item if it is editable.

### bool QListWidget::event ( QEvent * e )`[virtual protected]`

Reimplemented from QObject::event().

### QList<QListWidgetItem *> QListWidget::findItems ( const QString & text, Qt::MatchFlags flags ) const

Finds items with the text that matches the string text using the given flags.

### QModelIndex QListWidget::indexFromItem ( QListWidgetItem * item ) const`[protected]`

Returns the QModelIndex assocated with the given item.

### void QListWidget::insertItem ( int row, QListWidgetItem * item )

Inserts the item at the position in the list given by row.

See also addItem().

### void QListWidget::insertItem ( int row, const QString & label )

Inserts an item with the text label in the list widget at the position given by row.

See also addItem().

### void QListWidget::insertItems ( int row, const QStringList & labels )

Inserts items from the list of labels into the list, starting at the given row.

See also insertItem() and addItem().

### QListWidgetItem * QListWidget::item ( int row ) const

Returns the item that occupies the given row in the list if one has been set; otherwise returns 0.

See also row().

### void QListWidget::itemActivated ( QListWidgetItem * item )`[signal]`

This signal is emitted when the item is activated. The item is activated when the user clicks or double clicks on it, depending on the system configuration. It is also activated when the user presses the activation key (on Windows and X11 this is the Return key, on Mac OS X it is Ctrl+0).

### QListWidgetItem * QListWidget::itemAt ( const QPoint & p ) const

Returns a pointer to the item at the coordinates p. The coordinates are relative to the list widget's viewport().

### QListWidgetItem * QListWidget::itemAt ( int x, int y ) const

This is an overloaded function.

Returns a pointer to the item at the coordinates (x, y). The coordinates are relative to the list widget's viewport().

### void QListWidget::itemChanged ( QListWidgetItem * item )`[signal]`

This signal is emitted whenever the data of item has changed.

### void QListWidget::itemClicked ( QListWidgetItem * item )`[signal]`

This signal is emitted with the specified item when a mouse button is clicked on an item in the widget.

See also itemPressed() and itemDoubleClicked().

### void QListWidget::itemDoubleClicked ( QListWidgetItem * item )`[signal]`

This signal is emitted with the specified item when a mouse button is double clicked on an item in the widget.

See also itemClicked() and itemPressed().

### void QListWidget::itemEntered ( QListWidgetItem * item )`[signal]`

This signal is emitted when the mouse cursor enters an item. The item is the item entered. This signal is only emitted when mouseTracking is turned on, or when a mouse button is pressed while moving into an item.

See also QWidget::setMouseTracking().

### QListWidgetItem * QListWidget::itemFromIndex ( const QModelIndex & index ) const`[protected]`

Returns a pointer to the QListWidgetItem assocated with the given index.

### void QListWidget::itemPressed ( QListWidgetItem * item )`[signal]`

This signal is emitted with the specified item when a mouse button is pressed on an item in the widget.

See also itemClicked() and itemDoubleClicked().

### void QListWidget::itemSelectionChanged ()`[signal]`

This signal is emitted whenever the selection changes.

See also selectedItems(), QListWidgetItem::isSelected(), and currentItemChanged().

### QWidget * QListWidget::itemWidget ( QListWidgetItem * item ) const

Returns the widget displayed in the given item.

This function was introduced in Qt 4.1.

See also setItemWidget().

### QList<QListWidgetItem *> QListWidget::items ( const QMimeData * data ) const`[protected]`

Returns a list of pointers to the items contained in the data object. If the object was not created by a QListWidget in the same process, the list is empty.

### QMimeData * QListWidget::mimeData ( const QList<QListWidgetItem *> items ) const`[virtual protected]`

Returns an object that contains a serialized description of the specified items. The format used to describe the items is obtained from the mimeTypes() function.

If the list of items is empty, 0 is returned instead of a serialized empty list.

### QStringList QListWidget::mimeTypes () const`[virtual protected]`

Returns a list of MIME types that can be used to describe a list of listwidget items.

See also mimeData().

### void QListWidget::openPersistentEditor ( QListWidgetItem * item )

Opens an editor for the given item. The editor remains open after editing.

See also closePersistentEditor().

### void QListWidget::removeItemWidget ( QListWidgetItem * item )

Removes the widget set on the given item.

This function was introduced in Qt 4.3.

### int QListWidget::row ( const QListWidgetItem * item ) const

Returns the row containing the given item.

See also item().

### void QListWidget::scrollToItem ( const QListWidgetItem * item, QAbstractItemView::ScrollHint hint = EnsureVisible )`[slot]`

Scrolls the view if necessary to ensure that the item is visible.

hint specifies where the item should be located after the operation.

### QList<QListWidgetItem *> QListWidget::selectedItems () const

Returns a list of all selected items in the list widget.

### void QListWidget::setCurrentItem ( QListWidgetItem * item )

Sets the current item to item.

Unless the selection mode is NoSelection, the item is also be selected.

See also currentItem().

### void QListWidget::setCurrentItem ( QListWidgetItem * item, QItemSelectionModel::SelectionFlags command )

Set the current item to item, using the given command.

This function was introduced in Qt 4.4.

### void QListWidget::setItemWidget ( QListWidgetItem * item, QWidget * widget )

Sets the widget to be displayed in the give item.

This function should only be used to display static content in the place of a list widget item. If you want to display custom dynamic content or implement a custom editor widget, use QListView and subclass QItemDelegate instead.

This function was introduced in Qt 4.1.

See also itemWidget() and Delegate Classes.

### void QListWidget::sortItems ( Qt::SortOrder order = Qt::AscendingOrder )

Sorts all the items in the list widget according to the specified order.

### Qt::DropActions QListWidget::supportedDropActions () const`[virtual protected]`

Returns the drop actions supported by this view.

See also Qt::DropActions.

### QListWidgetItem * QListWidget::takeItem ( int row )

Removes and returns the item from the given row in the list widget; otherwise returns 0.

Items removed from a list widget will not be managed by Qt, and will need to be deleted manually.

See also insertItem() and addItem().

### QRect QListWidget::visualItemRect ( const QListWidgetItem * item ) const

Returns the rectangle on the viewport occupied by the item at item.