com.google.gwt.activity.shared

Interface Activity

All Known Implementing Classes:

AbstractActivity

public interface Activity

Implemented by objects that control a piece of user interface, with a life cycle managed by an ActivityManager, in response to PlaceChangeEvent events as the user navigates through the app.

Method Summary

Modifier and Type	Method and Description
String	mayStop() Called when the user is trying to navigate away from this activity.
void	onCancel() Called when start(com.google.gwt.user.client.ui.AcceptsOneWidget, com.google.gwt.event.shared.EventBus) has not yet replied to its callback, but the user has lost interest.
void	onStop() Called when the Activity's widget has been removed from view.
void	start(AcceptsOneWidget panel, EventBus eventBus) Called when the Activity should ready its widget for the user.

Method Detail

mayStop

String mayStop()

Called when the user is trying to navigate away from this activity.

Returns:

A message to display to the user, e.g. to warn of unsaved work, or null to say nothing

onCancel

void onCancel()

Called when start(com.google.gwt.user.client.ui.AcceptsOneWidget, com.google.gwt.event.shared.EventBus) has not yet replied to its callback, but the user has lost interest.

onStop

void onStop()

Called when the Activity's widget has been removed from view. All event handlers it registered will have been removed before this method is called.

start

void start(AcceptsOneWidget panel,
           EventBus eventBus)

Called when the Activity should ready its widget for the user. When the widget is ready (typically after an RPC response has been received), receiver should present it by calling AcceptsOneWidget.setWidget(com.google.gwt.user.client.ui.IsWidget) on the given panel.

Any handlers attached to the provided event bus will be de-registered when the activity is stopped, so activities will rarely need to hold on to the HandlerRegistration instances returned by EventBus.addHandler(com.google.web.bindery.event.shared.Event.Type<H>, H).

Parameters:

panel - the panel to display this activity's widget when it is ready

eventBus - the event bus