eu.webtoolkit.jwt
Class WTreeView

java.lang.Object
  eu.webtoolkit.jwt.WObject
      eu.webtoolkit.jwt.WWidget
          eu.webtoolkit.jwt.WCompositeWidget
              eu.webtoolkit.jwt.WAbstractItemView
                  eu.webtoolkit.jwt.WTreeView

public class WTreeView
extends WAbstractItemView

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.

The rendering (and editing) of items is handled by a WAbstractItemDelegate, by default it uses WItemDelegate which renders data of all predefined roles (see also ItemDataRole), including text, icons, checkboxes, and tooltips.

The view may support editing of items, if the model indicates support (see the ItemFlag.ItemIsEditable flag). You can define triggers that initiate editing of an item using WAbstractItemView#setEditTriggers(). The actual editing is provided by the item delegate (you can set an appropriate delegate for one column using WAbstractItemView#setItemDelegateForColumn()). Using WAbstractItemView#setEditOptions() you can customize if and how the view deals with multiple editors.

By default, all but the first columns are given a width of 150px, and the first column takes the remaining size. Note that this may have as consequence that the first column's size is reduced to 0. Column widths of all columns, including the first column, can be set through the API method setColumnWidth(), and also by the user using handles provided in the header.

Optionally, the treeview may be configured so that the first column is always visible while scrolling through the other columns, which may be convenient if you wish to display a model with many columns. Use setColumn1Fixed() to enable this behaviour.

If the model supports sorting ( WAbstractItemModel#sort()), such as the WStandardItemModel, then you can enable sorting buttons in the header, using WAbstractItemView#setSortingEnabled().

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

You may enable drag & drop support for this view, whith awareness of the items in the model. When enabling dragging (see WAbstractItemView#setDragEnabled()), the current selection may be dragged, but only when all items in the selection indicate support for dragging (controlled by the ItemIsDragEnabled flag), and if the model indicates a mime-type (controlled by WAbstractItemModel#getMimeType()). Likewise, by enabling support for dropping (see WAbstractItemView#setDropsEnabled()), the treeview may receive a drop event on a particular item, at least if the item indicates support for drops (controlled by the ItemIsDropEnabled flag).

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

Graceful degradation

The view provides a virtual scrolling behavior which relies on Ajax availability. When Ajax is not available, a page navigation bar is used instead, see WAbstractItemView#getCreatePageNavigationBar(). In that case, the widget needs to be given an explicit height using resize() which determines the number of rows that are displayed at a time.

CSS

The treeview is styled by the current CSS theme. The look can be overridden using the Wt-treeview CSS class and the following selectors.

Selectors that apply to the header:

 .Wt-treeview .Wt-headerdiv         : header (background)
 .Wt-treeview .Wt-header .Wt-label  : header label
 .Wt-treeview .Wt-tv-rh             : column resize handle
 .Wt-treeview .Wt-tv-sh-none        : column sort handle, no sorting
 .Wt-treeview .Wt-tv-sh-up          : column sort handle, sort up
 .Wt-treeview .Wt-tv-sh-down        : column sort handle, sort down
 

Selectors that apply to the tree decoration:

 .Wt-treeview .Wt-trunk          : vertical line, trunk
 .Wt-treeview .Wt-end            : vertical line, last item
 .Wt-treeview .Wt-collapse       : collapse icon
 .Wt-treeview .Wt-expand         : expand icon
 .Wt-treeview .Wt-noexpand       : leaf icon
 

Selectors that apply to the table contents:

 .Wt-treeview .Wt-spacer         : spacer for non-loaded content
 .Wt-treeview .Wt-selected       : selected item
 .Wt-treeview .Wt-drop-site      : possible drop site
 

Selectors that apply to the table borders (which must be 1 pixel wide)

 .Wt-treeview .Wt-tv-row .Wt-tv-c      : border-right property of cells
 .Wt-treeview .Wt-header .Wt-tv-row,
   .Wt-treeview .Wt-tv-node .Wt-tv-row : border-left property of cells
 

A snapshot of the WTreeView:

WTreeView example (default)

WTreeView example (polished)

Nested Class Summary

Nested classes/interfaces inherited from class eu.webtoolkit.jwt.WAbstractItemView

WAbstractItemView.EditOption, WAbstractItemView.EditTrigger

Constructor Summary

WTreeView()
Creates a new tree view.

WTreeView(WContainerWidget parent)
Creates a new tree view.

Method Summary

void	collapse(WModelIndex index) Collapses a node.
Signal1<WModelIndex>	collapsed() Signal emitted when a node is collapsed.
protected void	enableAjax() Progresses to an Ajax-enabled widget.
void	expand(WModelIndex index) Expands a node.
Signal1<WModelIndex>	expanded() Signal emitted when a node is expanded.
void	expandToDepth(int depth) Expands all nodes to a depth.
int	getCurrentPage() Returns the current page.
int	getPageCount() Returns the number of pages.
int	getPageSize() Returns the page size.
boolean	isColumn1Fixed() Returns whether horizontal scrolling includes the first column.
boolean	isExpanded(WModelIndex index) Returns whether a node is expanded.
boolean	isRootDecorated() Returns whether toplevel items are decorated.
void	remove() Destructor.
void	resize(WLength width, WLength height) Resizes the widget.
void	setAlternatingRowColors(boolean enable) Sets if alternating row colors are to be used.
void	setColumn1Fixed(boolean fixed) Configures whether horizontal scrolling includes the first column.
void	setColumnBorder(WColor color) Sets the column border color.
void	setColumnWidth(int column, WLength width) Sets the column width.
void	setCurrentPage(int page) Sets the current page.
void	setExpanded(WModelIndex index, boolean expanded) Expands or collapses a node.
void	setHeaderHeight(WLength height, boolean multiLine) Sets the header height.
void	setModel(WAbstractItemModel model) Sets the model.
void	setRootIsDecorated(boolean show) Sets whether toplevel items are decorated.
void	setRowHeight(WLength rowHeight) Sets the row height.

Methods inherited from class eu.webtoolkit.jwt.WAbstractItemView

clicked, closeEditor, closeEditor, closeEditors, closeEditors, columnResized, createExtraHeaderWidget, doubleClicked, dropEvent, edit, extraHeaderWidget, getColumnAlignment, getColumnWidth, getCreatePageNavigationBar, getEditOptions, getEditTriggers, getHeaderAlignment, getHeaderHeight, getItemDelegate, getItemDelegate, getItemDelegate, getItemDelegateForColumn, getModel, getRootIndex, getRowHeight, getSelectedIndexes, getSelectionBehavior, getSelectionMode, getSelectionModel, hasAlternatingRowColors, isColumnResizeEnabled, isEditing, isSelected, isSortingEnabled, isSortingEnabled, isValid, mouseWentDown, mouseWentUp, pageChanged, select, select, selectionChanged, setColumnAlignment, setColumnResizeEnabled, setDragEnabled, setDropsEnabled, setEditOptions, setEditOptions, setEditTriggers, setEditTriggers, setHeaderAlignment, setHeaderHeight, setItemDelegate, setItemDelegateForColumn, setRootIndex, setSelectedIndexes, setSelectionBehavior, setSelectionMode, setSortingEnabled, setSortingEnabled, sortByColumn, validateEditor, validateEditors

Methods inherited from class eu.webtoolkit.jwt.WCompositeWidget

addStyleClass, boxBorder, boxPadding, callJavaScriptMember, find, getAttributeValue, getClearSides, getDecorationStyle, getFloatSide, getHeight, getId, getImplementation, getJavaScriptMember, getLineHeight, getMargin, getMaximumHeight, getMaximumWidth, getMinimumHeight, getMinimumWidth, getOffset, getPositionScheme, getStyleClass, getTabIndex, getToolTip, getVerticalAlignment, getVerticalAlignmentLength, getWidth, isDisabled, isEnabled, isHidden, isHiddenKeepsGeometry, isInline, isLoaded, isPopup, load, propagateSetEnabled, refresh, removeStyleClass, setAttributeValue, setClearSides, setDecorationStyle, setDisabled, setFloatSide, setHidden, setHiddenKeepsGeometry, setId, setImplementation, setInline, setJavaScriptMember, setLineHeight, setMargin, setMaximumSize, setMinimumSize, setOffsets, setPopup, setPositionScheme, setSelectable, setStyleClass, setTabIndex, setToolTip, setVerticalAlignment

Methods inherited from class eu.webtoolkit.jwt.WWidget

acceptDrops, acceptDrops, addStyleClass, disable, dropEvent, enable, getDrop, getJsRef, getParent, hasParent, hide, htmlText, isRendered, layoutSizeChanged, positionAt, positionAt, removeStyleClass, resize, setClearSides, setLayoutSizeAware, setMargin, setMargin, setMargin, setMargin, setMargin, setOffsets, setOffsets, setOffsets, setOffsets, setOffsets, setTabOrder, setVerticalAlignment, show, stopAcceptDrops, tr

Methods inherited from class eu.webtoolkit.jwt.WObject

getObjectName, setObjectName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WTreeView

public WTreeView(WContainerWidget parent)

Creates a new tree view.

WTreeView

public WTreeView()

Creates a new tree view.

Calls this((WContainerWidget)null)

Method Detail

remove

public void remove()

Description copied from class: WWidget

Destructor.

Deletes a widget and all children (recursively). If the widget is contained in another widget, it is removed first.

Overrides:

remove in class WAbstractItemView

See Also:

WContainerWidget.removeWidget(WWidget widget)

setExpanded

public void setExpanded(WModelIndex index,
                        boolean expanded)

Expands or collapses a node.

See Also:

expand(WModelIndex index), collapse(WModelIndex index)

isExpanded

public boolean isExpanded(WModelIndex index)

Returns whether a node is expanded.

See Also:

setExpanded(WModelIndex index, boolean expanded)

collapse

public void collapse(WModelIndex index)

Collapses a node.

See Also:

setExpanded(WModelIndex index, boolean expanded), expand(WModelIndex index)

expand

public void expand(WModelIndex index)

Expands a node.

See Also:

setExpanded(WModelIndex index, boolean expanded), collapse(WModelIndex index)

expandToDepth

public void expandToDepth(int depth)

Expands all nodes to a depth.

Expands all nodes to the given depth. A depth of 1 corresponds to the top level nodes.

See Also:

expand(WModelIndex index)

setRootIsDecorated

public void setRootIsDecorated(boolean show)

Sets 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. You could also consider using a WTableView instead.

isRootDecorated

public boolean isRootDecorated()

Returns whether toplevel items are decorated.

See Also:

setRootIsDecorated(boolean show)

setColumn1Fixed

public void setColumn1Fixed(boolean fixed)

Configures whether horizontal scrolling includes the first column.

To display a model with many columns, this option allows you to keep the first column fixed while scrolling through the other columns of the model.

The default value is false.

Note: Currently, you must set this option before any other manipulation of a newly created treeview, and only enable = true is supported.

isColumn1Fixed

public boolean isColumn1Fixed()

Returns whether horizontal scrolling includes the first column.

See Also:

setColumn1Fixed(boolean fixed)

resize

public void resize(WLength width,
                   WLength height)

Description copied from class: WWidget

Resizes 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, and only block widgets can be given a size reliably.

When inserted in a layout manager, the widget may be informed about its current size using setLayoutSizeAware(). If you have defined a "wtResize()" JavaScript method for the widget, then this method will also be called. operation.

Overrides:

resize in class WCompositeWidget

See Also:

WWidget.getWidth(), WWidget.getHeight()

collapsed

public Signal1<WModelIndex> collapsed()

Signal emitted when a node is collapsed.

See Also:

setExpanded(WModelIndex index, boolean expanded), expanded()

expanded

public Signal1<WModelIndex> expanded()

Signal emitted when a node is expanded.

See Also:

setExpanded(WModelIndex index, boolean expanded), collapsed()

setModel

public void setModel(WAbstractItemModel model)

Description copied from class: WAbstractItemView

Sets the model.

The View will display data of the given model and changes in the model are reflected by the View.

The initial model is null.

Overrides:

setModel in class WAbstractItemView

See Also:

WAbstractItemView.setRootIndex(WModelIndex rootIndex)

setColumnWidth

public void setColumnWidth(int column,
                           WLength width)

Sets the column width.

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.

Note: The actual space occupied by each column is the column width augmented by 7 pixels for internal padding and a border.

Specified by:

setColumnWidth in class WAbstractItemView

See Also:

setRowHeight(WLength rowHeight)

setAlternatingRowColors

public void setAlternatingRowColors(boolean enable)

Description copied from class: WAbstractItemView

Sets if alternating row colors are to be used.

Configure whether rows get alternating background colors, defined by the current CSS theme.

The default value is false.

Overrides:

setAlternatingRowColors in class WAbstractItemView

setRowHeight

public void setRowHeight(WLength rowHeight)

Description copied from class: WAbstractItemView

Sets the row height.

The view renders all rows with a same height. This method configures this row height.

The default value is 20 pixels.

Note: The height must be specified in WLength.Unit.Pixel units.

Overrides:

setRowHeight in class WAbstractItemView

See Also:

WAbstractItemView.setColumnWidth(int column, WLength width)

setHeaderHeight

public void setHeaderHeight(WLength height,
                            boolean multiLine)

Description copied from class: WAbstractItemView

Sets the header height.

Use this method to change the header height. By default, the header text is a single line that is centered vertically.

By enabling multi-line headers, the header text will be aligned to the top and wrap as needed. In that case, additional contents may be displayed in the header, provided by createExtraHeaderWidget().

The default value is a single line of 20 pixels.

Overrides:

setHeaderHeight in class WAbstractItemView

setColumnBorder

public void setColumnBorder(WColor color)

Description copied from class: WAbstractItemView

Sets the column border color.

The default border color is defined by the CSS theme.

Specified by:

setColumnBorder in class WAbstractItemView

getPageCount

public int getPageCount()

Description copied from class: WAbstractItemView

Returns the number of pages.

When Ajax/JavaScript is not available, the view will use a paging navigation bar to allow scrolling through the data. This returns the number of pages currently shown.

Specified by:

getPageCount in class WAbstractItemView

See Also:

WAbstractItemView.getCreatePageNavigationBar(), WAbstractItemView.pageChanged()

getPageSize

public int getPageSize()

Description copied from class: WAbstractItemView

Returns the page size.

When Ajax/JavaScript is not available, the view will use a paging navigation bar to allow scrolling through the data. This returns the number of items per page.

Specified by:

getPageSize in class WAbstractItemView

See Also:

WAbstractItemView.getCreatePageNavigationBar(), WAbstractItemView.pageChanged()

getCurrentPage

public int getCurrentPage()

Description copied from class: WAbstractItemView

Returns the current page.

When Ajax/JavaScript is not available, the view will use a paging navigation bar to allow scrolling through the data. This returns the current page (between 0 and getPageCount() - 1).

Specified by:

getCurrentPage in class WAbstractItemView

See Also:

WAbstractItemView.getCreatePageNavigationBar(), WAbstractItemView.pageChanged()

setCurrentPage

public void setCurrentPage(int page)

Description copied from class: WAbstractItemView

Sets the current page.

When Ajax/JavaScript is not available, the view will use a paging navigation bar to allow scrolling through the data. This method can be used to change the current page.

Specified by:

setCurrentPage in class WAbstractItemView

See Also:

WAbstractItemView.getCreatePageNavigationBar(), WAbstractItemView.pageChanged()

enableAjax

protected void enableAjax()

Description copied from class: WWidget

Progresses to an Ajax-enabled widget.

This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

Overrides:

enableAjax in class WCompositeWidget

See Also:

WApplication.enableAjax()