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

java.lang.Object
  com.google.gwt.user.client.ui.UIObject
      com.google.gwt.user.client.ui.Widget

All Implemented Interfaces:

EventListener

Direct Known Subclasses:

Composite, FileUpload, FocusWidget, Frame, Hidden, Hyperlink, Image, Label, MenuBar, Panel, Tree

public class Widget
extends UIObject
implements EventListener

The base class for the majority of user-interface objects. Widget adds support for receiving events from the browser and being added directly to panels.

Constructor Summary

Widget()

Method Summary

Widget	getParent() Gets this widget's parent panel.
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.
protected void	onLoad() This method is called when the widget becomes attached to the browser's document.
void	removeFromParent() Removes this widget from its parent widget.

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

addStyleName, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleName, getTitle, isVisible, isVisible, removeStyleName, setElement, setHeight, setPixelSize, setSize, setStyleName, setStyleName, setTitle, setVisible, setVisible, setWidth, sinkEvents, toString, unsinkEvents

Methods inherited from class java.lang.Object

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

Constructor Detail

Widget

public Widget()

Method Detail

getParent

public Widget getParent()

Gets this widget's parent panel.

Returns:

the widget's parent panel

isAttached

public 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).

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

Parameters:

event - the event received

removeFromParent

public void removeFromParent()

Removes this widget from its parent widget. If it has no parent, this method does nothing.

Throws:

java.lang.IllegalStateException - if this widget's parent does not support removal (e.g. Composite)

onAttach

protected void onAttach()

This method is called when a widget is attached to the browser's document. It must not be overridden, except by Panel. To receive notification when a widget is attached to the document, override the onLoad() method.

onDetach

protected void onDetach()

This method is called when a widget is detached from the browser's document. It must not be overridden, except by Panel.

onLoad

protected void onLoad()

This method is called when the widget becomes attached to the browser's document.