com.google.gwt.user.client.ui

Class Composite

java.lang.Object

com.google.gwt.user.client.ui.UIObject

com.google.gwt.user.client.ui.Widget

com.google.gwt.user.client.ui.Composite

All Implemented Interfaces:

HasAttachHandlers, HasHandlers, EventListener, HasVisibility, IsRenderable, IsWidget

Direct Known Subclasses:

AbstractCellTree, AbstractHasData, AbstractPager, CalendarView, CaptionPanel, DateBox, DatePicker, DisclosurePanel, MonthSelector, NotificationMole, ResizeComposite, SuggestBox, TabBar, TabPanel, ValueBoxEditorDecorator, ValueListBox, ValuePicker

public abstract class Composite
extends Widget
implements IsRenderable

A type of widget that can wrap another widget, hiding the wrapped widget's methods. When added to a panel, a composite behaves exactly as if the widget it wraps had been added.

The composite is useful for creating a single widget out of an aggregate of multiple other widgets contained in a single panel.

Example

Nested Class Summary

Nested classes/interfaces inherited from class com.google.gwt.user.client.ui.UIObject

UIObject.DebugIdImpl, UIObject.DebugIdImplEnabled

Field Summary

Fields inherited from class com.google.gwt.user.client.ui.UIObject

DEBUG_ID_PREFIX

Constructor Summary

Constructors

Constructor and Description
Composite()

Method Summary

Methods

Modifier and Type	Method and Description
void	claimElement(Element element) Replace the previous contents of the receiver with the given element, presumed to have been created and stamped via a previous call to IsRenderable.render(com.google.gwt.user.client.ui.RenderableStamper).
protected Widget	getWidget() Provides subclasses access to the topmost widget that defines this composite.
void	initializeClaimedElement() Perform any initialization needed when the widget is not attached to the document.
protected void	initWidget(Widget widget) Sets the widget to be wrapped by the composite.
boolean	isAttached() Determines whether this widget is currently attached to the browser's document (i.e., there is an unbroken chain of widgets between this widget and the underlying browser document).
protected void	onAttach() This method is called when a widget is attached to the browser's document.
void	onBrowserEvent(Event event) Fired whenever a browser event is received.
protected void	onDetach() This method is called when a widget is detached from the browser's document.
SafeHtml	render(RenderableStamper stamper)
void	render(RenderableStamper stamper, SafeHtmlBuilder builder) Tells this object to render itself as HTML and append it to the given builder.
protected Element	resolvePotentialElement() EXPERIMENTAL and subject to change.
protected void	setWidget(Widget widget) Deprecated. Use initWidget(Widget) instead

Methods inherited from class com.google.gwt.user.client.ui.Widget

addAttachHandler, addBitlessDomHandler, addDomHandler, addHandler, asWidget, asWidgetOrNull, createHandlerManager, delegateEvent, doAttachChildren, doDetachChildren, fireEvent, getHandlerCount, getLayoutData, getParent, isOrWasAttached, onLoad, onUnload, removeFromParent, setLayoutData, sinkEvents, unsinkEvents

Methods inherited from class com.google.gwt.user.client.ui.UIObject

addStyleDependentName, addStyleName, ensureDebugId, ensureDebugId, ensureDebugId, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleElement, getStyleName, getStyleName, getStylePrimaryName, getStylePrimaryName, getTitle, isVisible, isVisible, onEnsureDebugId, removeStyleDependentName, removeStyleName, setElement, setElement, setHeight, setPixelSize, setSize, setStyleDependentName, setStyleName, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkBitlessEvent, toString

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode

Constructor Detail

Composite

public Composite()

Method Detail

claimElement

public void claimElement(Element element)

Description copied from interface: IsRenderable

Replace the previous contents of the receiver with the given element, presumed to have been created and stamped via a previous call to IsRenderable.render(com.google.gwt.user.client.ui.RenderableStamper).

Specified by:

claimElement in interface IsRenderable

initializeClaimedElement

public void initializeClaimedElement()

Description copied from interface: IsRenderable

Perform any initialization needed when the widget is not attached to the document. Assumed to be called after IsRenderable.claimElement(com.google.gwt.dom.client.Element).

Specified by:

initializeClaimedElement in interface IsRenderable

isAttached

public boolean isAttached()

Description copied from class: Widget

Determines whether this widget is currently attached to the browser's document (i.e., there is an unbroken chain of widgets between this widget and the underlying browser document).

Specified by:

isAttached in interface HasAttachHandlers

Overrides:

isAttached in class Widget

Returns:

true if the widget is attached

onBrowserEvent

public void onBrowserEvent(Event event)

Description copied from interface: EventListener

Fired whenever a browser event is received.

Specified by:

onBrowserEvent in interface EventListener

Overrides:

onBrowserEvent in class Widget

Parameters:

event - the event received

render

public SafeHtml render(RenderableStamper stamper)

Specified by:

render in interface IsRenderable

See Also:

TODO(rdcastro): Remove this once UiBinder doesn't rely on it anymore.

render

public void render(RenderableStamper stamper,
          SafeHtmlBuilder builder)

Description copied from interface: IsRenderable

Tells this object to render itself as HTML and append it to the given builder. If the implementation expects to be able to claim an element later, it must be marked by the given stamper.

Specified by:

render in interface IsRenderable

getWidget

protected Widget getWidget()

Provides subclasses access to the topmost widget that defines this composite.

Returns:

the widget

initWidget

protected void initWidget(Widget widget)

Sets the widget to be wrapped by the composite. The wrapped widget must be set before calling any Widget methods on this object, or adding it to a panel. This method may only be called once for a given composite.

Parameters:

widget - the widget to be wrapped

onAttach

protected void onAttach()

Description copied from class: Widget

This method is called when a widget is attached to the browser's document. To receive notification after a Widget has been added to the document, override the Widget.onLoad() method or use Widget.addAttachHandler(com.google.gwt.event.logical.shared.AttachEvent.Handler).

It is strongly recommended that you override Widget.onLoad() or Widget.doAttachChildren() instead of this method to avoid inconsistencies between logical and physical attachment states.

Subclasses that override this method must call super.onAttach() to ensure that the Widget has been attached to its underlying Element.

Overrides:

onAttach in class Widget

See Also:

Widget.onLoad(), Widget.doAttachChildren()

onDetach

protected void onDetach()

Description copied from class: Widget

This method is called when a widget is detached from the browser's document. To receive notification before a Widget is removed from the document, override the Widget.onUnload() method or use Widget.addAttachHandler(com.google.gwt.event.logical.shared.AttachEvent.Handler).

It is strongly recommended that you override Widget.onUnload() or Widget.doDetachChildren() instead of this method to avoid inconsistencies between logical and physical attachment states.

Subclasses that override this method must call super.onDetach() to ensure that the Widget has been detached from the underlying Element. Failure to do so will result in application memory leaks due to circular references between DOM Elements and JavaScript objects.

Overrides:

onDetach in class Widget

See Also:

Widget.onUnload(), Widget.doDetachChildren()

resolvePotentialElement

protected Element resolvePotentialElement()

Description copied from class: UIObject

EXPERIMENTAL and subject to change. Do not use this in production code.

To be overridden by IsRenderable subclasses that initialize themselves by by calling setElement(PotentialElement.build(this)).

The receiver must:

• create a real Element to replace its PotentialElement
• call #setElement() with the new Element
• and return the new Element

This method is called when the receiver's element is about to be added to a parent node, as a side effect of DOM.appendChild(com.google.gwt.dom.client.Element, com.google.gwt.dom.client.Element).

Note that this method is normally called only on the top element of an IsRenderable tree. Children instead will receive IsRenderable.render(com.google.gwt.user.client.ui.RenderableStamper) and IsRenderable.claimElement(Element).

Overrides:

resolvePotentialElement in class UIObject

See Also:

PotentialElement, IsRenderable

setWidget

@Deprecated
protected void setWidget(Widget widget)

Deprecated. Use initWidget(Widget) instead

This method was for initializing the Widget to be wrapped by this Composite, but has been deprecated in favor of initWidget(Widget).