QListView Class
The QListView class provides a list or icon view onto a model. More...
| Header: | #include <QListView> |
| qmake: | QT += widgets |
| Inherits: | QAbstractItemView |
| Inherited By: | 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
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Public Functions
| QListView(QWidget *parent = nullptr) | |
| virtual | ~QListView() |
| int | batchSize() const |
| void | clearPropertyFlags() |
| QListView::Flow | flow() const |
| QSize | gridSize() const |
| bool | isRowHidden(int row) const |
| bool | isSelectionRectVisible() const |
| bool | isWrapping() const |
| Qt::Alignment | itemAlignment() const |
| QListView::LayoutMode | layoutMode() const |
| int | modelColumn() const |
| QListView::Movement | movement() const |
| QListView::ResizeMode | resizeMode() const |
| void | setBatchSize(int batchSize) |
| void | setFlow(QListView::Flow flow) |
| void | setGridSize(const QSize &size) |
| void | setItemAlignment(Qt::Alignment alignment) |
| void | setLayoutMode(QListView::LayoutMode mode) |
| void | setModelColumn(int column) |
| void | setMovement(QListView::Movement movement) |
| void | setResizeMode(QListView::ResizeMode mode) |
| void | setRowHidden(int row, bool hide) |
| void | setSelectionRectVisible(bool show) |
| void | setSpacing(int space) |
| void | setUniformItemSizes(bool enable) |
| void | setViewMode(QListView::ViewMode mode) |
| void | setWordWrap(bool on) |
| void | setWrapping(bool enable) |
| int | spacing() const |
| bool | uniformItemSizes() const |
| QListView::ViewMode | viewMode() const |
| bool | wordWrap() const |
Reimplemented Public Functions
| virtual QModelIndex | indexAt(const QPoint &p) const override |
| virtual void | scrollTo(const QModelIndex &index, QAbstractItemView::ScrollHint hint = EnsureVisible) override |
| virtual QRect | visualRect(const QModelIndex &index) const override |
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 ¤t, const QModelIndex &previous) override |
| virtual void | dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles = QVector<int>()) override |
| virtual void | dragLeaveEvent(QDragLeaveEvent *e) override |
| virtual void | dragMoveEvent(QDragMoveEvent *e) override |
| virtual void | dropEvent(QDropEvent *event) override |
| virtual bool | event(QEvent *e) override |
| virtual int | horizontalOffset() const override |
| virtual bool | isIndexHidden(const QModelIndex &index) const override |
| virtual void | mouseMoveEvent(QMouseEvent *e) override |
| virtual void | mouseReleaseEvent(QMouseEvent *e) override |
| virtual QModelIndex | moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers) override |
| virtual void | paintEvent(QPaintEvent *e) override |
| virtual void | resizeEvent(QResizeEvent *e) override |
| virtual void | rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end) override |
| virtual void | rowsInserted(const QModelIndex &parent, int start, int end) override |
| virtual QModelIndexList | selectedIndexes() const override |
| virtual void | selectionChanged(const QItemSelection &selected, const QItemSelection &deselected) override |
| virtual void | setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command) override |
| virtual void | startDrag(Qt::DropActions supportedActions) override |
| virtual void | timerEvent(QTimerEvent *e) override |
| virtual void | updateGeometries() override |
| virtual int | verticalOffset() const override |
| virtual QStyleOptionViewItem | viewOptions() const override |
| virtual QSize | viewportSizeHint() const override |
| virtual QRegion | visualRegionForSelection(const QItemSelection &selection) const override |
| virtual void | wheelEvent(QWheelEvent *e) override |
Detailed Description
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().
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, Item Views Puzzle Example, QTreeView, QTableView, and QListWidget.
Member Type Documentation
enum QListView::Flow
| Constant | Value | Description |
|---|---|---|
QListView::LeftToRight | 0 | The items are laid out in the view from the left to the right. |
QListView::TopToBottom | 1 | The items are laid out in the view from the top to the bottom. |
enum QListView::LayoutMode
| Constant | Value | Description |
|---|---|---|
QListView::SinglePass | 0 | The items are laid out all at once. |
QListView::Batched | 1 | The items are laid out in batches of batchSize items. |
See also batchSize.
enum QListView::Movement
| Constant | Value | Description |
|---|---|---|
QListView::Static | 0 | The items cannot be moved by the user. |
QListView::Free | 1 | The items can be moved freely by the user. |
QListView::Snap | 2 | The items snap to the specified grid when moved; see setGridSize(). |
enum QListView::ResizeMode
| Constant | Value | Description |
|---|---|---|
QListView::Fixed | 0 | The items will only be laid out the first time the view is shown. |
QListView::Adjust | 1 | The items will be laid out every time the view is resized. |
enum QListView::ViewMode
| Constant | Value | Description |
|---|---|---|
QListView::ListMode | 0 | The items are laid out using TopToBottom flow, with Small size and Static movement |
QListView::IconMode | 1 | The 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:
| QListView::Flow | flow() const |
| void | setFlow(QListView::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.
itemAlignment : Qt::Alignment
This property holds the alignment of each item in its cell
This is only supported in ListMode with TopToBottom flow and with wrapping enabled. The default alignment is 0, which means that an item fills its cell entirely.
This property was introduced in Qt 5.12.
Access functions:
| Qt::Alignment | itemAlignment() const |
| void | setItemAlignment(Qt::Alignment alignment) |
layoutMode : LayoutMode
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:
| QListView::LayoutMode | layoutMode() const |
| void | setLayoutMode(QListView::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:
| QListView::Movement | movement() const |
| void | setMovement(QListView::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:
| QListView::ResizeMode | resizeMode() const |
| void | setResizeMode(QListView::ResizeMode mode) |
See also movement, gridSize, and viewMode.
selectionRectVisible : bool
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:
| QListView::ViewMode | viewMode() const |
| void | setViewMode(QListView::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 = nullptr)
Creates a new QListView with the given parent to view a model. Use setModel() to set the model.
[signal] void QListView::indexesMoved(const QModelIndexList &indexes)
This signal is emitted when the specified indexes are moved in the view.
This function was introduced in Qt 4.2.
[virtual] 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().
[override virtual protected] void QListView::currentChanged(const QModelIndex ¤t, const QModelIndex &previous)
Reimplements: QAbstractItemView::currentChanged(const QModelIndex ¤t, const QModelIndex &previous).
[override virtual protected] void QListView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles = QVector<int>())
Reimplements: QAbstractItemView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles).
[override virtual protected] void QListView::dragLeaveEvent(QDragLeaveEvent *e)
Reimplements: QAbstractItemView::dragLeaveEvent(QDragLeaveEvent *event).
[override virtual protected] void QListView::dragMoveEvent(QDragMoveEvent *e)
Reimplements: QAbstractItemView::dragMoveEvent(QDragMoveEvent *event).
[override virtual protected] void QListView::dropEvent(QDropEvent *event)
Reimplements: QAbstractItemView::dropEvent(QDropEvent *event).
[override virtual protected] bool QListView::event(QEvent *e)
Reimplements: QAbstractItemView::event(QEvent *event).
[override virtual protected] int QListView::horizontalOffset() const
Reimplements: QAbstractItemView::horizontalOffset() const.
[override virtual] QModelIndex QListView::indexAt(const QPoint &p) const
Reimplements: QAbstractItemView::indexAt(const QPoint &point) const.
[override virtual protected] bool QListView::isIndexHidden(const QModelIndex &index) const
Reimplements: QAbstractItemView::isIndexHidden(const QModelIndex &index) const.
bool QListView::isRowHidden(int row) const
Returns true if the row is hidden; otherwise returns false.
[override virtual protected] void QListView::mouseMoveEvent(QMouseEvent *e)
Reimplements: QAbstractItemView::mouseMoveEvent(QMouseEvent *event).
[override virtual protected] void QListView::mouseReleaseEvent(QMouseEvent *e)
Reimplements: QAbstractItemView::mouseReleaseEvent(QMouseEvent *event).
[override virtual protected] QModelIndex QListView::moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
Reimplements: QAbstractItemView::moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers).
[override virtual protected] void QListView::paintEvent(QPaintEvent *e)
Reimplements: QAbstractScrollArea::paintEvent(QPaintEvent *event).
[protected] QRect QListView::rectForIndex(const QModelIndex &index) const
Returns the rectangle of the item at position index in the model. The rectangle is in contents coordinates.
See also visualRect().
[override virtual protected] void QListView::resizeEvent(QResizeEvent *e)
Reimplements: QAbstractItemView::resizeEvent(QResizeEvent *event).
[override virtual protected] void QListView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
Reimplements: QAbstractItemView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end).
[override virtual protected] void QListView::rowsInserted(const QModelIndex &parent, int start, int end)
Reimplements: QAbstractItemView::rowsInserted(const QModelIndex &parent, int start, int end).
[override virtual] void QListView::scrollTo(const QModelIndex &index, QAbstractItemView::ScrollHint hint = EnsureVisible)
Reimplements: QAbstractItemView::scrollTo(const QModelIndex &index, QAbstractItemView::ScrollHint hint).
[override virtual protected] QModelIndexList QListView::selectedIndexes() const
Reimplements: QAbstractItemView::selectedIndexes() const.
[override virtual protected] void QListView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
Reimplements: QAbstractItemView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected).
[protected] void QListView::setPositionForIndex(const QPoint &position, const QModelIndex &index)
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().
[override virtual protected] void QListView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
Reimplements: QAbstractItemView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags flags).
[override virtual protected] void QListView::startDrag(Qt::DropActions supportedActions)
Reimplements: QAbstractItemView::startDrag(Qt::DropActions supportedActions).
[override virtual protected] void QListView::timerEvent(QTimerEvent *e)
Reimplements: QAbstractItemView::timerEvent(QTimerEvent *event).
[override virtual protected] void QListView::updateGeometries()
Reimplements: QAbstractItemView::updateGeometries().
[override virtual protected] int QListView::verticalOffset() const
Reimplements: QAbstractItemView::verticalOffset() const.
[override virtual protected] QStyleOptionViewItem QListView::viewOptions() const
Reimplements: QAbstractItemView::viewOptions() const.
[override virtual protected] QSize QListView::viewportSizeHint() const
Reimplements: QAbstractItemView::viewportSizeHint() const.
This function was introduced in Qt 5.2.
[override virtual] QRect QListView::visualRect(const QModelIndex &index) const
Reimplements: QAbstractItemView::visualRect(const QModelIndex &index) const.
[override virtual protected] QRegion QListView::visualRegionForSelection(const QItemSelection &selection) const
Reimplements: QAbstractItemView::visualRegionForSelection(const QItemSelection &selection) const.
Since 4.7, the returned region only contains rectangles intersecting (or included in) the viewport.
[override virtual protected] void QListView::wheelEvent(QWheelEvent *e)
Reimplements: QAbstractScrollArea::wheelEvent(QWheelEvent *e).
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