Package eu.webtoolkit.jwt

Class WItemDelegate

java.lang.Object
eu.webtoolkit.jwt.WObject
eu.webtoolkit.jwt.WAbstractItemDelegate
eu.webtoolkit.jwt.WItemDelegate
public class WItemDelegate
extends WAbstractItemDelegate
Standard delegate class for rendering a view item.

This class provides the standard implementation for rendering an item (as in a WAbstractItemView), and renders data provided by the standard data roles (see ItemDataRole). It also provides default editing support using a line edit.

You may provide special editing support for an item by specializing the widget and reimplement createEditor(), setModelData(), getEditState(), and setEditState().

  • Constructor Details

    • WItemDelegate

      public WItemDelegate​(WObject parent)
      Create an item delegate.

    • WItemDelegate

      public WItemDelegate()
      Create an item delegate.

      Calls this((WObject)null)

  • Method Details

    • update

      public WWidget update​(WWidget widget, WModelIndex index, java.util.EnumSet<ViewItemRenderFlag> flags)
      Creates or updates a widget that renders an item.

      The following properties of an item are rendered:

      When the flags indicates ViewItemRenderFlag.RenderEditing, then createEditor() is called to create a suitable editor for editing the item.

      Specified by:
      update in class WAbstractItemDelegate

    • updateModelIndex

      public void updateModelIndex​(WWidget widget, WModelIndex index)
      Description copied from class: WAbstractItemDelegate
      Updates the model index of a widget.

      This method is invoked by the view when due to row/column insertions or removals, the index has shifted.

      You should reimplement this method only if you are storing the model index in the widget, to update the stored model index.

      The default implementation does nothing.

      Overrides:
      updateModelIndex in class WAbstractItemDelegate

    • setTextFormat

      public void setTextFormat​(java.lang.String format)
      Sets the text format string.

      The DisplayRole data is converted to a string using StringUtils.asString(Object), passing the given format. If the format is an empty string, this corresponds to Object.toString().

      The default value is "".

    • getTextFormat

      public java.lang.String getTextFormat()
      Returns the text format string.

      See Also:
      setTextFormat(String format)

    • setModelData

      public void setModelData​(java.lang.Object editState, WAbstractItemModel model, WModelIndex index)
      Saves the edited data to the model.

      The default implementation saves the current edit value to the model. You will need to reimplement this method for a custom editor.

      As an example of how to deal with a specialized editor, consider the default implementation: 

      
 public void setModelData(Object editState, WAbstractItemModel model, WModelIndex index) {
 model.setData(index, editState, ItemDataRole.EditRole);
 }

      Overrides:
      setModelData in class WAbstractItemDelegate
      See Also:
      createEditor(WModelIndex index, EnumSet flags), getEditState(WWidget editor)

    • getEditState

      public java.lang.Object getEditState​(WWidget editor)
      Returns the current edit state.

      The default implementation returns the current text in the line edit. You will need to reimplement this method for a custom editor.

      As an example of how to deal with a specialized editor, consider the default implementation: 

      
 public Object getEditState(WWidget editor) {
 WContainerWidget w = (WContainerWidget) editor;
 WLineEdit lineEdit = (WLineEdit) w.getWidget(0);
 return lineEdit.getText();
 }

      Overrides:
      getEditState in class WAbstractItemDelegate
      See Also:
      createEditor(WModelIndex index, EnumSet flags), setEditState(WWidget editor, Object value), setModelData(Object editState, WAbstractItemModel model, WModelIndex index)

    • setEditState

      public void setEditState​(WWidget editor, java.lang.Object value)
      Sets the editor data from the editor state.

      The default implementation resets the text in the line edit. You will need to reimplement this method if for a custom editor.

      As an example of how to deal with a specialized editor, consider the default implementation: 

      
 public void setEditState(WWidget editor, Object value) {
 WContainerWidget w = (WContainerWidget) editor;
 WLineEdit lineEdit = (WLineEdit) w.getWidget(0);
 lineEdit.setText((String) value);
 }

      Overrides:
      setEditState in class WAbstractItemDelegate
      See Also:
      createEditor(WModelIndex index, EnumSet flags)

    • createEditor

      protected WWidget createEditor​(WModelIndex index, java.util.EnumSet<ViewItemRenderFlag> flags)
      Creates an editor for a data item.

      The default implementation returns a WLineEdit which edits the item's ItemDataRole.EditRole value.

      You may reimplement this method to provide a suitable editor, or to attach a custom validator. In that case, you will probably also want to reimplement getEditState(), setEditState(), and setModelData().

      The editor should not keep a reference to the model index (it does not need to since setModelData() will provide the proper model index to save the data to the model). Otherwise, because model indexes may shift because of row or column insertions, you should reimplement updateModelIndex().

      As an example of how to provide a specialized editor, consider the default implementation, which returns a WLineEdit: 

      
 protected WWidget createEditor(WModelIndex index, EnumSet&lt;ViewItemRenderFlag&gt; flags) {
 final WContainerWidget result = new WContainerWidget();
 result.setSelectable(true);
 WLineEdit lineEdit = new WLineEdit();
 lineEdit.setText(StringUtils.asString(index.getData(ItemDataRole.EditRole), this.textFormat_).toString());
 lineEdit.enterPressed().addListener(this, new Signal.Listener() {
 public void trigger() {
 WItemDelegate.this.closeEditor().trigger(result, true);
 }
 });
 lineEdit.escapePressed().addListener(this, new Signal.Listener() {
 public void trigger() {
 WItemDelegate.this.closeEditor().trigger(result, false);
 }
 });

 if (flags.contains(ViewItemRenderFlag.RenderFocused))
 lineEdit.setFocus();

 result.setLayout(new WHBoxLayout());
 result.getLayout().setContentsMargins(1, 1, 1, 1);
 result.getLayout().addWidget(lineEdit);
 return result;
 }

    • createEditor

      protected final WWidget createEditor​(WModelIndex index, ViewItemRenderFlag flag, ViewItemRenderFlag... flags)
      Creates an editor for a data item.

      Returns createEditor(index, EnumSet.of(flag, flags))