eu.webtoolkit.jwt
Class WAbstractItemDelegate

java.lang.Object
  eu.webtoolkit.jwt.WObject
      eu.webtoolkit.jwt.WAbstractItemDelegate

Direct Known Subclasses:

WItemDelegate

public abstract class WAbstractItemDelegate
extends WObject

Abstract delegate class for rendering a view item.

Rendering of an item in a WTreeView is delegated to an implementation of this delegate class. The default implementation used by WTreeView is WItemDelegate. To provide specialized rendering support, you can reimplement this class, and indicate to the treeview to use this delegate for rendering items.

As a delegate is used for rendering multiple items, the class should not keep state about one specific item.

An example of a delegate that always renders the text in a line-edit, and saves the modified value back to the (editable) model.

See Also:

WAbstractItemView.setItemDelegate(WAbstractItemDelegate delegate), WAbstractItemView.setItemDelegateForColumn(int column, WAbstractItemDelegate delegate)

Constructor Summary

WAbstractItemDelegate()
Constructor.

WAbstractItemDelegate(WObject parent)
Constructor.

Method Summary

abstract WWidget	update(WWidget widget, WModelIndex index, java.util.EnumSet<ViewItemRenderFlag> flags) Creates or updates a widget that renders an item.
WWidget	update(WWidget widget, WModelIndex index, ViewItemRenderFlag flag, ViewItemRenderFlag... flags) Creates or updates a widget that renders an item.
void	updateModelIndex(WWidget widget, WModelIndex index) Updates the model index of a widget.

Methods inherited from class eu.webtoolkit.jwt.WObject

getId, getObjectName, remove, setObjectName, tr

Methods inherited from class java.lang.Object

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

Constructor Detail

WAbstractItemDelegate

public WAbstractItemDelegate(WObject parent)

Constructor.

WAbstractItemDelegate

public WAbstractItemDelegate()

Constructor.

Calls this((WObject)null)

Method Detail

update

public abstract WWidget update(WWidget widget,
                               WModelIndex index,
                               java.util.EnumSet<ViewItemRenderFlag> flags)

Creates or updates a widget that renders an item.

The item is specified by its model index, which also indicates the model. If an existing widget already renders the item, but needs to be updated, it is passed as the widget parameter. You may decide to create a new widget, in which case you are responsible to delete the previous widget if it is not reused.

When widget is null, a new widget needs to be created.

The flags parameter indicates options for rendering the item.

update

public final WWidget update(WWidget widget,
                            WModelIndex index,
                            ViewItemRenderFlag flag,
                            ViewItemRenderFlag... flags)

Creates or updates a widget that renders an item.

Returns update(widget, index, EnumSet.of(flag, flags))

updateModelIndex

public void updateModelIndex(WWidget widget,
                             WModelIndex index)

Updates the model index of a widget.

This method is invoked by the view when due to row/column insertions or removals, an index was modified for a widget.

You should reimplement this method if you are storing the model index (e.g. for editing purposes) in the widget, which you should update to the new index.

The default implementation does nothing.