QListView Class Reference

The QListView class provides a list or icon view onto a model. More...

 #include <QListView>

Inherits: QAbstractItemView.

Inherited by: QHelpIndexWidget, QListWidget, and QUndoView.

Public Types

enum Flow { LeftToRight, TopToBottom }
enum LayoutMode { SinglePass, Batched }
enum Movement { Static, Free, Snap }
enum ResizeMode { Fixed, Adjust }
enum ViewMode { ListMode, IconMode }

Properties

Public Functions

QListView ( QWidget * parent = 0 )
~QListView ()
int batchSize () const
void clearPropertyFlags ()
Flow flow () const
QSize gridSize () const
bool isRowHidden ( int row ) const
bool isSelectionRectVisible () const
bool isWrapping () const
LayoutMode layoutMode () const
int modelColumn () const
Movement movement () const
ResizeMode resizeMode () const
void setBatchSize ( int batchSize )
void setFlow ( Flow flow )
void setGridSize ( const QSize & size )
void setLayoutMode ( LayoutMode mode )
void setModelColumn ( int column )
void setMovement ( Movement movement )
void setResizeMode ( ResizeMode mode )
void setRowHidden ( int row, bool hide )
void setSelectionRectVisible ( bool show )
void setSpacing ( int space )
void setUniformItemSizes ( bool enable )
void setViewMode ( ViewMode mode )
void setWordWrap ( bool on )
void setWrapping ( bool enable )
int spacing () const
bool uniformItemSizes () const
ViewMode viewMode () const
bool wordWrap () const

Reimplemented Public Functions

virtual QModelIndex indexAt ( const QPoint & p ) const
virtual void scrollTo ( const QModelIndex & index, ScrollHint hint = EnsureVisible )
virtual QRect visualRect ( const QModelIndex & index ) const

Signals

void indexesMoved ( const QModelIndexList & indexes )

Protected Functions

QRect rectForIndex ( const QModelIndex & index ) const
void setPositionForIndex ( const QPoint & position, const QModelIndex & index )

Reimplemented Protected Functions

virtual void currentChanged ( const QModelIndex & current, const QModelIndex & previous )
virtual void dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight )
virtual void dragLeaveEvent ( QDragLeaveEvent * e )
virtual void dragMoveEvent ( QDragMoveEvent * e )
virtual void dropEvent ( QDropEvent * e )
virtual bool event ( QEvent * e )
virtual int horizontalOffset () const
virtual bool isIndexHidden ( const QModelIndex & index ) const
virtual void mouseMoveEvent ( QMouseEvent * e )
virtual void mouseReleaseEvent ( QMouseEvent * e )
virtual QModelIndex moveCursor ( CursorAction cursorAction, Qt::KeyboardModifiers modifiers )
virtual void paintEvent ( QPaintEvent * e )
virtual void resizeEvent ( QResizeEvent * e )
virtual void rowsAboutToBeRemoved ( const QModelIndex & parent, int start, int end )
virtual void rowsInserted ( const QModelIndex & parent, int start, int end )
virtual QModelIndexList selectedIndexes () const
virtual void selectionChanged ( const QItemSelection & selected, const QItemSelection & deselected )
virtual void setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags command )
virtual void startDrag ( Qt::DropActions supportedActions )
virtual void timerEvent ( QTimerEvent * e )
virtual void updateGeometries ()
virtual int verticalOffset () const
virtual QStyleOptionViewItem viewOptions () const
virtual QRegion visualRegionForSelection ( const QItemSelection & selection ) const

Additional Inherited Members

Detailed Description

The QListView class provides a list or icon view onto a model.

A QListView presents items stored in a model, either as a simple non-hierarchical list, or as a collection of icons. This class is used to provide lists and icon views that were previously provided by the QListBox and QIconView classes, but using the more flexible approach provided by Qt's model/view architecture.

The QListView class is one of the Model/View Classes and is part of Qt's model/view framework.

This view does not display horizontal or vertical headers; to display a list of items with a horizontal header, use QTreeView instead.

QListView implements the interfaces defined by the QAbstractItemView class to allow it to display data provided by models derived from the QAbstractItemModel class.

Items in a list view can be displayed using one of two view modes: In ListMode, the items are displayed in the form of a simple list; in IconMode, the list view takes the form of an icon view in which the items are displayed with icons like files in a file manager. By default, the list view is in ListMode. To change the view mode, use the setViewMode() function, and to determine the current view mode, use viewMode().

Items in these views are laid out in the direction specified by the flow() of the list view. The items may be fixed in place, or allowed to move, depending on the view's movement() state.

If the items in the model cannot be completely laid out in the direction of flow, they can be wrapped at the boundary of the view widget; this depends on isWrapping(). This property is useful when the items are being represented by an icon view.

The resizeMode() and layoutMode() govern how and when the items are laid out. Items are spaced according to their spacing(), and can exist within a notional grid of size specified by gridSize(). The items can be rendered as large or small icons depending on their iconSize().

Screenshot of a Windows XP style list viewScreenshot of a Macintosh style table viewScreenshot of a Plastique style table view
A Windows XP style list view.A Macintosh style list view.A Plastique style list view.

Improving Performance

It is possible to give the view hints about the data it is handling in order to improve its performance when displaying large numbers of items. One approach that can be taken for views that are intended to display items with equal sizes is to set the uniformItemSizes property to true.

See also View Classes, QTreeView, QTableView, and QListWidget.

Member Type Documentation

enum QListView::Flow

ConstantValueDescription
QListView::LeftToRight0The items are laid out in the view from the left to the right.
QListView::TopToBottom1The items are laid out in the view from the top to the bottom.

enum QListView::LayoutMode

ConstantValueDescription
QListView::SinglePass0The items are laid out all at once.
QListView::Batched1The items are laid out in batches of batchSize items.

See also batchSize.

enum QListView::Movement

ConstantValueDescription
QListView::Static0The items cannot be moved by the user.
QListView::Free1The items can be moved freely by the user.
QListView::Snap2The items snap to the specified grid when moved; see setGridSize().

enum QListView::ResizeMode

ConstantValueDescription
QListView::Fixed0The items will only be laid out the first time the view is shown.
QListView::Adjust1The items will be laid out every time the view is resized.

enum QListView::ViewMode

ConstantValueDescription
QListView::ListMode0The items are laid out using TopToBottom flow, with Small size and Static movement
QListView::IconMode1The items are laid out using LeftToRight flow, with Large size and Free movement

Property Documentation

batchSize : int

This property holds the number of items laid out in each batch if layoutMode is set to Batched.

The default value is 100.

This property was introduced in Qt 4.2.

Access functions:

int batchSize () const
void setBatchSize ( int batchSize )

flow : Flow

This property holds which direction the items layout should flow.

If this property is LeftToRight, the items will be laid out left to right. If the isWrapping property is true, the layout will wrap when it reaches the right side of the visible area. If this property is TopToBottom, the items will be laid out from the top of the visible area, wrapping when it reaches the bottom.

Setting this property when the view is visible will cause the items to be laid out again.

By default, this property is set to TopToBottom.

Access functions:

Flow flow () const
void setFlow ( Flow flow )

See also viewMode.

gridSize : QSize

This property holds the size of the layout grid.

This property is the size of the grid in which the items are laid out. The default is an empty size which means that there is no grid and the layout is not done in a grid. Setting this property to a non-empty size switches on the grid layout. (When a grid layout is in force the spacing property is ignored.)

Setting this property when the view is visible will cause the items to be laid out again.

Access functions:

QSize gridSize () const
void setGridSize ( const QSize & size )

See also viewMode.

isWrapping : bool

This property holds whether the items layout should wrap.

This property holds whether the layout should wrap when there is no more space in the visible area. The point at which the layout wraps depends on the flow property.

Setting this property when the view is visible will cause the items to be laid out again.

By default, this property is false.

Access functions:

bool isWrapping () const
void setWrapping ( bool enable )

See also viewMode.

layoutMode : LayoutMode

This property determines whether the layout of items should happen immediately or be delayed.

This property holds the layout mode for the items. When the mode is SinglePass (the default), the items are laid out all in one go. When the mode is Batched, the items are laid out in batches of batchSize items, while processing events. This makes it possible to instantly view and interact with the visible items while the rest are being laid out.

Access functions:

LayoutMode layoutMode () const
void setLayoutMode ( LayoutMode mode )

See also viewMode.

modelColumn : int

This property holds the column in the model that is visible.

By default, this property contains 0, indicating that the first column in the model will be shown.

Access functions:

int modelColumn () const
void setModelColumn ( int column )

movement : Movement

This property holds whether the items can be moved freely, are snapped to a grid, or cannot be moved at all.

This property determines how the user can move the items in the view. Static means that the items can't be moved the user. Free means that the user can drag and drop the items to any position in the view. Snap means that the user can drag and drop the items, but only to the positions in a notional grid signified by the gridSize property.

Setting this property when the view is visible will cause the items to be laid out again.

By default, this property is set to Static.

Access functions:

Movement movement () const
void setMovement ( Movement movement )

See also gridSize, resizeMode, and viewMode.

resizeMode : ResizeMode

This property holds whether the items are laid out again when the view is resized.

If this property is Adjust, the items will be laid out again when the view is resized. If the value is Fixed, the items will not be laid out when the view is resized.

By default, this property is set to Fixed.

Access functions:

ResizeMode resizeMode () const
void setResizeMode ( ResizeMode mode )

See also movement, gridSize, and viewMode.

selectionRectVisible : bool

This property holds if the selection rectangle should be visible.

If this property is true then the selection rectangle is visible; otherwise it will be hidden.

Note: The selection rectangle will only be visible if the selection mode is in a mode where more than one item can be selected; i.e., it will not draw a selection rectangle if the selection mode is QAbstractItemView::SingleSelection.

By default, this property is false.

This property was introduced in Qt 4.3.

Access functions:

bool isSelectionRectVisible () const
void setSelectionRectVisible ( bool show )

spacing : int

This property holds the space around the items in the layout.

This property is the size of the empty space that is padded around an item in the layout.

Setting this property when the view is visible will cause the items to be laid out again.

By default, this property contains a value of 0.

Access functions:

int spacing () const
void setSpacing ( int space )

See also viewMode.

uniformItemSizes : bool

This property holds whether all items in the listview have the same size.

This property should only be set to true if it is guaranteed that all items in the view have the same size. This enables the view to do some optimizations for performance purposes.

By default, this property is false.

This property was introduced in Qt 4.1.

Access functions:

bool uniformItemSizes () const
void setUniformItemSizes ( bool enable )

viewMode : ViewMode

This property holds the view mode of the QListView.

This property will change the other unset properties to conform with the set view mode. QListView-specific properties that have already been set will not be changed, unless clearPropertyFlags() has been called.

Setting the view mode will enable or disable drag and drop based on the selected movement. For ListMode, the default movement is Static (drag and drop disabled); for IconMode, the default movement is Free (drag and drop enabled).

Access functions:

ViewMode viewMode () const
void setViewMode ( ViewMode mode )

See also isWrapping, spacing, gridSize, flow, movement, and resizeMode.

wordWrap : bool

This property holds the item text word-wrapping policy.

If this property is true then the item text is wrapped where necessary at word-breaks; otherwise it is not wrapped at all. This property is false by default.

Please note that even if wrapping is enabled, the cell will not be expanded to make room for the text. It will print ellipsis for text that cannot be shown, according to the view's textElideMode.

This property was introduced in Qt 4.2.

Access functions:

bool wordWrap () const
void setWordWrap ( bool on )

Member Function Documentation

QListView::QListView ( QWidget * parent = 0 )

Creates a new QListView with the given parent to view a model. Use setModel() to set the model.

QListView::~QListView ()

Destroys the view.

void QListView::clearPropertyFlags ()

Clears the QListView-specific property flags. See viewMode.

Properties inherited from QAbstractItemView are not covered by the property flags. Specifically, dragEnabled and acceptsDrops are computed by QListView when calling setMovement() or setViewMode().

void QListView::currentChanged ( const QModelIndex & current, const QModelIndex & previous ) [virtual protected]

Reimplemented from QAbstractItemView::currentChanged().

void QListView::dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight ) [virtual protected]

Reimplemented from QAbstractItemView::dataChanged().

void QListView::dragLeaveEvent ( QDragLeaveEvent * e ) [virtual protected]

Reimplemented from QWidget::dragLeaveEvent().

void QListView::dragMoveEvent ( QDragMoveEvent * e ) [virtual protected]

Reimplemented from QWidget::dragMoveEvent().

void QListView::dropEvent ( QDropEvent * e ) [virtual protected]

Reimplemented from QWidget::dropEvent().

bool QListView::event ( QEvent * e ) [virtual protected]

Reimplemented from QObject::event().

int QListView::horizontalOffset () const [virtual protected]

Reimplemented from QAbstractItemView::horizontalOffset().

QModelIndex QListView::indexAt ( const QPoint & p ) const [virtual]

Reimplemented from QAbstractItemView::indexAt().

void QListView::indexesMoved ( const QModelIndexList & indexes ) [signal]

This signal is emitted when the specified indexes are moved in the view.

This function was introduced in Qt 4.2.

bool QListView::isIndexHidden ( const QModelIndex & index ) const [virtual protected]

Reimplemented from QAbstractItemView::isIndexHidden().

bool QListView::isRowHidden ( int row ) const

Returns true if the row is hidden; otherwise returns false.

void QListView::mouseMoveEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseMoveEvent().

void QListView::mouseReleaseEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseReleaseEvent().

QModelIndex QListView::moveCursor ( CursorAction cursorAction, Qt::KeyboardModifiers modifiers ) [virtual protected]

Reimplemented from QAbstractItemView::moveCursor().

void QListView::paintEvent ( QPaintEvent * e ) [virtual protected]

Reimplemented from QWidget::paintEvent().

QRect QListView::rectForIndex ( const QModelIndex & index ) const [protected]

Returns the rectangle of the item at position index in the model. The rectangle is in contents coordinates.

See also visualRect().

void QListView::resizeEvent ( QResizeEvent * e ) [virtual protected]

Reimplemented from QWidget::resizeEvent().

void QListView::rowsAboutToBeRemoved ( const QModelIndex & parent, int start, int end ) [virtual protected]

Reimplemented from QAbstractItemView::rowsAboutToBeRemoved().

void QListView::rowsInserted ( const QModelIndex & parent, int start, int end ) [virtual protected]

Reimplemented from QAbstractItemView::rowsInserted().

void QListView::scrollTo ( const QModelIndex & index, ScrollHint hint = EnsureVisible ) [virtual]

Reimplemented from QAbstractItemView::scrollTo().

QModelIndexList QListView::selectedIndexes () const [virtual protected]

Reimplemented from QAbstractItemView::selectedIndexes().

void QListView::selectionChanged ( const QItemSelection & selected, const QItemSelection & deselected ) [virtual protected]

Reimplemented from QAbstractItemView::selectionChanged().

void QListView::setPositionForIndex ( const QPoint & position, const QModelIndex & index ) [protected]

Sets the contents position of the item at index in the model to the given position. If the list view's movement mode is Static or its view mode is ListView, this function will have no effect.

This function was introduced in Qt 4.1.

void QListView::setRowHidden ( int row, bool hide )

If hide is true, the given row will be hidden; otherwise the row will be shown.

See also isRowHidden().

void QListView::setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags command ) [virtual protected]

Reimplemented from QAbstractItemView::setSelection().

void QListView::startDrag ( Qt::DropActions supportedActions ) [virtual protected]

Reimplemented from QAbstractItemView::startDrag().

void QListView::timerEvent ( QTimerEvent * e ) [virtual protected]

Reimplemented from QObject::timerEvent().

void QListView::updateGeometries () [virtual protected]

Reimplemented from QAbstractItemView::updateGeometries().

int QListView::verticalOffset () const [virtual protected]

Reimplemented from QAbstractItemView::verticalOffset().

QStyleOptionViewItem QListView::viewOptions () const [virtual protected]

Reimplemented from QAbstractItemView::viewOptions().

QRect QListView::visualRect ( const QModelIndex & index ) const [virtual]

Reimplemented from QAbstractItemView::visualRect().

QRegion QListView::visualRegionForSelection ( const QItemSelection & selection ) const [virtual protected]

Reimplemented from QAbstractItemView::visualRegionForSelection().

Since 4.7, the returned region only contains rectangles intersecting (or included in) the viewport.

Notes provided by the Qt Community
Informative
  • 0

Votes: 0

Coverage: Qt library 4.7, Qt 4.8, 5

Picture of billconan billconan

Ant Farmer
6 notes

Basic ListView model example

  1. class ListViewModel : public QAbstractListModel
  2. {
  3. public:
  4.     ListViewModel(QObject *parent = 0) {}
  5.  
  6.     int rowCount ( const QModelIndex & parent = QModelIndex() ) const
  7.     {
  8.         return 10;
  9.     }
  10.  
  11.     QVariant data ( const QModelIndex & index, int role = Qt::DisplayRole ) const
  12.     {
  13.         if (role == Qt::DisplayRole)
  14.             return QString("haha");
  15.         return QVariant();
  16.     }
  17. };

you need to be careful about the data() function. Only return the right data for the right role. for unimplemented data roles, you need to return QVariant();

otherwise, you might see weird problems. for example, the following code tries to create a list of text “haha”, but it will result in an empty listview, because when Qt queries data for role == SizeHintRole, we return a string, which is an invalid size. so Qt ends up drawing a size(0,0) entry in the listview.

  1.    
  2.     QVariant data ( const QModelIndex & index, int role = Qt::DisplayRole ) const
  3.     {            
  4.           return QString("haha");
  5.     }

[Revisions]