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GWT - Widget Class
Introduction
The class Widget is 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.
Class Declaration
Following is the declaration for com.google.gwt.user.client.ui.Widget class −
public class Widget extends UIObject implements EventListener
Field
Following are the fields for com.google.gwt.user.client.ui.Widget class −
public static final java.lang.String DEBUG_ID_PREFIX − The element ID that you specify will be prefixed by the static string DEBUG_ID_PREFIX.
Class Constructors
Sr.No. | Constructor & Description |
---|---|
1 |
Widget() This creates a Widget for the child classes. |
Class Methods
Sr.No. | Method & Description |
---|---|
1 |
protected <H extends EventHandler> HandlerRegistration addDomHandler(H handler, DomEvent.Type<H> type) Adds a native event handler to the widget and sinks the corresponding native event. |
2 |
protected <H extends EventHandler> HandlerRegistration addHandler(H handler, GwtEvent.Type<H> type) Adds this handler to the widget. |
3 |
protected void delegateEvent(Widget target, GwtEvent<?> event) Fires an event on a child widget. |
4 |
protected void doAttachChildren() If a widget implements HasWidgets, it must override this method and call onAttach() for each of its child widgets. |
5 |
protected void doDetachChildren() If a widget implements HasWidgets, it must override this method and call onDetach() for each of its child widgets. |
6 |
void fireEvent(GwtEvent<?> event) Fires the given event to all the appropriate handlers. |
7 |
protected int getHandlerCount(GwtEvent.Type<?> type) Gets the number of handlers listening to the event type. |
8 |
Widget getParent() Gets this widget's parent panel. |
9 |
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). |
10 |
protected boolean isOrWasAttached() Has this widget ever been attached? |
11 |
protected void onAttach() This method is called when a widget is attached to the browser's document. |
12 |
void onBrowserEvent(Event event) Fired whenever a browser event is received. |
13 |
protected void onDetach() This method is called when a widget is detached from the browser's document. |
14 |
protected void onLoad() Gets a handle to the object's underlying DOM element. |
15 |
protected void onUnload() This method is called immediately before a widget will be detached from the browser's document. |
16 |
void removeFromParent() Removes this widget from its parent widget. |
17 |
void sinkEvents(int eventBitsToAdd) Overridden to defer the call to super.sinkEvents until the first time this widget is attached to the dom, as a performance enhancement. |
Methods Inherited
This class inherits methods from the following classes −
com.google.gwt.user.client.ui.UIObject