Wt::WTreeView Class Reference
[Model/view system]

A view class that displays a model as a tree or tree table. More...

#include <Wt/WTreeView>

Inheritance diagram for Wt::WTreeView:

Inheritance graph
[legend]

List of all members.

Public Member Functions

 WTreeView (WContainerWidget *parent)
 Create a new tree view.
 ~WTreeView ()
 Destructor.
void setModel (WAbstractItemModel *model)
 Set the model.
WAbstractItemModelmodel () const
 Returns the model.
void setRootIndex (const WModelIndex &rootIndex)
 Set the root index.
const WModelIndexrootIndex () const
 Returns the root index.
void setHeaderHeight (const WLength &height)
 Set the row height.
const WLengthheaderHeight () const
 Return the header height.
void setRowHeight (const WLength &rowHeight)
 Set the row height.
const WLengthrowHeight () const
 Return the row height.
void setColumnWidth (int column, const WLength &width)
 Set the column width.
WLength columnWidth (int column) const
 Returns the column width.
void setColumnAlignment (int column, HorizontalAlignment alignment)
 Set the content alignment for a column.
HorizontalAlignment columnAlignment (int column) const
 Returns the content alignment for a column.
void setImagePack (const std::string &uri)
 Sets the base urls for icons.
std::string imagePack () const
 Returns the base url for icons.
void setExpanded (const WModelIndex &, bool expanded)
 Expand or collapse a node.
bool isExpanded (const WModelIndex &index) const
 Returns whether a node is expanded.
void collapse (const WModelIndex &index)
 Collapse a node.
void expand (const WModelIndex &index)
 Expand a node.
void setAlternatingRowColors (bool enable)
 Set if alternating row colors are to be used.
bool alternatingRowColors () const
 Returns whether alternating row colors are used.
void setRootIsDecorated (bool show)
 Set whether toplevel items are decorated.
bool rootIsDecorated () const
 Returns whether toplevel items are decorated.
void sortByColumn (int column, SortOrder order)
 Sort the data according to a column.
void setSortingEnabled (bool enabled)
 Enable sorting.
bool isSortingEnabled () const
 Returns whether sorting is enabled.
void setSelectionBehavior (SelectionBehavior behavior)
 Change the selection behaviour.
SelectionBehavior selectionBehavior () const
 Returns the selection behaviour.
void setSelectionMode (SelectionMode mode)
 Set the selection mode.
SelectionMode selectionMode () const
 Returns the selection mode.
void setSelectedIndexes (const WModelIndexSet &indexes)
 Sets the selected items.
void select (const WModelIndex &index, SelectionFlag option=Select)
 Select a single item.
bool isSelected (const WModelIndex &index) const
 Returns wheter an item is selected.
WModelIndexSet selectedIndexes () const
 Returns the set of selected items.
virtual void resize (const WLength &width, const WLength &height)
 Resize the widget.
virtual void load ()
 Load content just before the widget's content is rendered.

Public Attributes

Signal< WModelIndexcollapsed
 Signal emitted when a node is collapsed.
Signal< WModelIndexexpanded
 Signal emitted when a node is expanded.
Signal< WModelIndexclicked
 Signal emitted when an item is clicked.
Signal< WModelIndexdoubleClicked
 Signal emitted when an item is double clicked.
Signal< void > selectionChanged
 Signal emitted when the selection is changed.


Detailed Description

A view class that displays a model as a tree or tree table.

The view displays data from a WAbstractItemModel in a tree or tree table. It provides incremental rendering, allowing the display of data models of any size efficiently, without excessive use of client- or serverside resources. Data of all predefined roles is displayed (see also ItemDataRole), including text, icons, checkboxes, and tooltips .

By default, all but the first columns are given a width of 150px, and the first column takes the remaining size. This can be changed through the API (setColumnWidth(), and also by the user using handles provided in the header.

If the model supports sorting (WAbstractItemModel::sort()), then you can enable sorting buttons in the header, using setSortingEnabled().

You can allow selection on row or item level (using setSelectionBehavior()), and selection of single or multiple items (using setSelectionMode()), and listen for changes in the selection using the selectionChanged signal.

You may also react to mouse click events on any item, by connecting to one of the clicked or doubleClicked signals.

Note:
Column insertions and deletions are currently not updated in the view. Therefore you should make sure that columns are set in the model before using setModel() and never changed later.

Member Function Documentation

void Wt::WTreeView::setModel ( WAbstractItemModel model  ) 

Set the model.

The view will render the data in the given model. Changes to the model are reflected in the view.

When resetting a model, all nodes are initially collapsed, the selection is cleared, and the root index corresponds to the model's top level node (see setRootIndex()).

The initial model is 0.

Ownership of the model is not transferred (and thus the previously set model is not deleted).

See also:
setRootIndex()

WAbstractItemModel* Wt::WTreeView::model (  )  const [inline]

Returns the model.

See also:
setModel()

void Wt::WTreeView::setRootIndex ( const WModelIndex rootIndex  ) 

Set the root index.

The root index is the model index that is considered the root node. This node itself is not rendered, but all its children are the top level nodes.

The default value is WModelIndex(), corresponding to the invisible root.

See also:
setModel()

const WModelIndex& Wt::WTreeView::rootIndex (  )  const [inline]

Returns the root index.

See also:
setRootIndex()

void Wt::WTreeView::setHeaderHeight ( const WLength height  ) 

Set the row height.

The view assumes that all rows are of the same height. Use this method to set the height.

The default value is 20 pixels.

const WLength& Wt::WTreeView::headerHeight (  )  const [inline]

Return the header height.

See also:
setHeaderHeight()

void Wt::WTreeView::setRowHeight ( const WLength rowHeight  ) 

Set the row height.

The view assumes that all rows are of the same height. Use this method to set the height.

The default value is 20 pixels.

Note:
The height must be specified in WLength::Pixel units.
See also:
setColumnWidth()

void Wt::WTreeView::setColumnWidth ( int  column,
const WLength width 
)

Set the column width.

You can specify the column width for all columns, except for the first column.

For a model with columnCount() == N, the initial width of columns 1..N is set to 150 pixels, and column 0 will take all remaining space.

See also:
setRowHeight()

WLength Wt::WTreeView::columnWidth ( int  column  )  const

Returns the column width.

See also:
setColumnWidth()

void Wt::WTreeView::setColumnAlignment ( int  column,
HorizontalAlignment  alignment 
)

Set the content alignment for a column.

The default value is AlignLeft.

HorizontalAlignment Wt::WTreeView::columnAlignment ( int  column  )  const

Returns the content alignment for a column.

See also:
setColumnAlignment()

void Wt::WTreeView::setImagePack ( const std::string &  uri  ) 

Sets the base urls for icons.

This widget relies on several icons that are distributed together with Wt for drawing icons, lines, and backgrounds.

The default location for the image pack is resourcesURL.

The default value for resourcesURL is "resources/". This value may be overridden with a URL that points to a folder where these files are located, by configuring the resourcesURL property in your Wt configuration file.

std::string Wt::WTreeView::imagePack (  )  const [inline]

Returns the base url for icons.

See also:
setImagePack()

void Wt::WTreeView::setExpanded ( const WModelIndex ,
bool  expanded 
)

Expand or collapse a node.

See also:
expand(), collapse()

bool Wt::WTreeView::isExpanded ( const WModelIndex index  )  const

Returns whether a node is expanded.

See also:
setExpanded()

void Wt::WTreeView::collapse ( const WModelIndex index  ) 

Collapse a node.

See also:
setExpanded(), expand()

void Wt::WTreeView::expand ( const WModelIndex index  ) 

Expand a node.

See also:
setExpanded(), collapse()

void Wt::WTreeView::setAlternatingRowColors ( bool  enable  ) 

Set if alternating row colors are to be used.

Configure whether rows get an alternating background color. These are implemented by using a background image on the root node, like:

stripe-30px.gif

Sample image use for alternating row colors

The image that is used is imagePack() + "/stripes/stripe-<i>n</i>px.gif", where n is the row height. In the resource folder are images pregenerated for one color and row sizes from 10 to 30px.

The default value is false.

See also:
setImagePack()

bool Wt::WTreeView::alternatingRowColors (  )  const [inline]

Returns whether alternating row colors are used.

See also:
setAlternatingRowColors()

void Wt::WTreeView::setRootIsDecorated ( bool  show  ) 

Set whether toplevel items are decorated.

By default, top level nodes have expand/collapse and other lines to display their linkage and offspring, like any node.

By setting show to false, you can hide these decorations for root nodes, and in this way mimic a plain list.

See also:
Ext::TableView

bool Wt::WTreeView::rootIsDecorated (  )  const [inline]

Returns whether toplevel items are decorated.

See also:
setRootIsDecorated()

void Wt::WTreeView::sortByColumn ( int  column,
SortOrder  order 
)

Sort the data according to a column.

Sorts the data according to data in column column and sort order order.

See also:
WAbstractItemModel::sort()

void Wt::WTreeView::setSortingEnabled ( bool  enabled  ) 

Enable sorting.

Enable or disable sorting by the user.

Sorting is enabled by default.

See also:
WAbstractItemModel::sort()

bool Wt::WTreeView::isSortingEnabled (  )  const [inline]

Returns whether sorting is enabled.

See also:
setSortingEnabled()

void Wt::WTreeView::setSelectionBehavior ( SelectionBehavior  behavior  ) 

Change the selection behaviour.

By default, selection operates on rows (SelectRows), in which case model indexes will always be in the first column (column 0).

Alternatively, you can allow selection for individual items (SelectItems).

See also:
setSelectionMode()

SelectionBehavior Wt::WTreeView::selectionBehavior (  )  const [inline]

Returns the selection behaviour.

See also:
setSelectionBehavior()

void Wt::WTreeView::setSelectionMode ( SelectionMode  mode  ) 

Set the selection mode.

By default selection is disabled (NoSelection ).

See also:
setSelectionBehavior()

SelectionMode Wt::WTreeView::selectionMode (  )  const [inline]

Returns the selection mode.

See also:
setSelectionMode()

void Wt::WTreeView::setSelectedIndexes ( const WModelIndexSet &  indexes  ) 

Sets the selected items.

Replaces the current selection with indexes.

See also:
select()

void Wt::WTreeView::select ( const WModelIndex index,
SelectionFlag  option = Select 
)

Select a single item.

See also:
setSelectedIndexes()

bool Wt::WTreeView::isSelected ( const WModelIndex index  )  const

Returns wheter an item is selected.

See also:
selectedIndexes(), select()

WModelIndexSet Wt::WTreeView::selectedIndexes (  )  const [inline]

Returns the set of selected items.

The model indexes are returned as a set, topologically ordered (in the order they appear in the view).

See also:
setSelectedIndexes()

virtual void Wt::WTreeView::resize ( const WLength width,
const WLength height 
) [virtual]

Resize the widget.

Specify a new size for this widget, by specifying width and height. By default a widget has automatic width and height, see WLength::isAuto().

This applies to CSS-based layout.

See also:
width(), height()

Reimplemented from Wt::WCompositeWidget.

virtual void Wt::WTreeView::load (  )  [virtual]

Load content just before the widget's content is rendered.

As soon as a widget is inserted into the widget hierarchy, it is rendered. Visible widgets are rendered immediately, and invisible widgets in the back-ground. This method is called when the widget is directly or indirectly inserted into the widget tree.

The default implementation simply propagates the load signal to its children. You may want to override this method to load resource-intensive content only when the widget is loaded into the browser.

Reimplemented from Wt::WCompositeWidget.


Member Data Documentation

Signal emitted when a node is collapsed.

See also:
setExpanded(), expanded

Signal emitted when a node is expanded.

See also:
setExpanded(), collapsed

Signal emitted when an item is clicked.

See also:
doubleClicked

Signal emitted when an item is double clicked.

See also:
doubleClicked

Signal emitted when the selection is changed.

See also:
select(), setSelectionMode(), setSelectionBehavior()


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