QListView Class Reference
[QtGui module]

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

enum QListView::LayoutMode

See also batchSize.

enum QListView::Movement

enum QListView::ResizeMode

enum QListView::ViewMode

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 between 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 acceptDrops are computed by QListView when calling setMovement() or setViewMode().

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::isRowHidden ( int row ) const

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

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::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, 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().