public static class DelegatingFocusListenerCollection extends Object
FocusListenerCollection
used to correctly hook up listeners which
need to listen to events from another source.
For example, Composite
widgets often need to listen to events
generated on their wrapped widget. Upon the firing of a wrapped widget's
event, the composite widget must fire its own listeners with itself as the
source of the event. To use a DelegatingFocusListenerCollection
,
simply use the DelegatingFocusListenerCollection
instead of a
FocusListenerCollection
. For example, in SuggestBox
, the
following code is used to listen to focus events on the SuggestBox
's
underlying widget.
public void addFocusListener(FocusListener listener) { if (focusListeners == null) { focusListeners = new DelegatingFocusListenerCollection(this, box); } focusListeners.add(listener); }
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