Package com.vaadin.client.renderers

Class WidgetRenderer<T,W extends com.google.gwt.user.client.ui.Widget>

java.lang.Object

com.vaadin.client.renderers.ComplexRenderer<T>

com.vaadin.client.renderers.WidgetRenderer<T,W>

Type Parameters:

T - the row data type

W - the Widget type

All Implemented Interfaces:

Renderer<T>

Direct Known Subclasses:

ClickableRenderer, ProgressBarRenderer

public abstract class WidgetRenderer<T,W extends com.google.gwt.user.client.ui.Widget>
extends ComplexRenderer<T>

A renderer for rendering widgets into cells.

Since:

7.4

Author:

Vaadin Ltd

Constructor Summary

Constructors

Constructor	Description
WidgetRenderer()

Method Summary

Modifier and Type	Method	Description
abstract W	createWidget()	Creates a widget to attach to a cell.
protected W	getWidget(com.google.gwt.dom.client.TableCellElement e)	Returns the widget contained inside the given cell element.
protected static <W extends com.google.gwt.user.client.ui.Widget> W	getWidget(com.google.gwt.dom.client.TableCellElement e, Class<W> klass)	Returns the widget contained inside the given cell element, or null if it is not an instance of the given class.
void	init(RendererCellReference cell)	Called at initialization stage.
void	render(RendererCellReference cell, T data)	Called whenever the Grid updates a cell.
abstract void	render(RendererCellReference cell, T data, W widget)	Renders a cell with a widget.

Methods inherited from class com.vaadin.client.renderers.ComplexRenderer

destroy, destroy, getConsumedEvents, onActivate, onBrowserEvent, setContentVisible

Methods inherited from class java.lang.Object

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

Constructor Detail

WidgetRenderer

public WidgetRenderer()

Method Detail

init

public void init(RendererCellReference cell)

Description copied from class: ComplexRenderer

Called at initialization stage. Perform any initialization here e.g. attach handlers, attach widgets etc.

Specified by:

init in class ComplexRenderer<T>

Parameters:

cell - The cell. Note that the cell is not to be stored outside of the method as the cell instance will change. See FlyweightCell

createWidget

public abstract W createWidget()

Creates a widget to attach to a cell. The widgets will be attached to the cell after the cell element has been attached to DOM.

Returns:

widget to attach to a cell. All returned instances should be new widget instances without a parent.

render

public void render(RendererCellReference cell,
                   T data)

Description copied from interface: Renderer

Called whenever the Grid updates a cell.

For optimal performance, work done in this method should be kept to a minimum since it will be called continuously while the user is scrolling. It is recommended to set up the cell's DOM structure in ComplexRenderer.init(RendererCellReference) and only make incremental updates based on cell data in this method.

Parameters:

cell - The cell. Note that the cell is a flyweight and should not be stored outside of the method as it will change.

data - The column data object

render

public abstract void render(RendererCellReference cell,
                            T data,
                            W widget)

Renders a cell with a widget. This provides a way to update any information in the widget that is cell specific. Do not detach the Widget here, it will be done automatically by the Grid when the widget is no longer needed.

For optimal performance, work done in this method should be kept to a minimum since it will be called continuously while the user is scrolling. The renderer can use Widget.setLayoutData(Object) to store cell data that might be needed in e.g. event listeners.

Parameters:

cell - The cell to render. Note that the cell is a flyweight and should not be stored and used outside of this method as its contents will change.

data - the data of the cell

widget - the widget embedded in the cell

getWidget

protected W getWidget(com.google.gwt.dom.client.TableCellElement e)

Returns the widget contained inside the given cell element. Cannot be called for cells that do not contain a widget.

Parameters:

e - the element inside which to find a widget

Returns:

the widget inside the element

getWidget

protected static <W extends com.google.gwt.user.client.ui.Widget> W getWidget(com.google.gwt.dom.client.TableCellElement e,
                                                                              Class<W> klass)

Returns the widget contained inside the given cell element, or null if it is not an instance of the given class. Cannot be called for cells that do not contain a widget.

Parameters:

e - the element inside to find a widget

klass - the type of the widget to find

Returns:

the widget inside the element, or null if its type does not match