KeyEventDispatcherpublic interface KeyEventDispatcher | A KeyEventDispatcher cooperates with the current KeyboardFocusManager in the
targeting and dispatching of all KeyEvents. KeyEventDispatchers registered
with the current KeyboardFocusManager will receive KeyEvents before they are
dispatched to their targets, allowing each KeyEventDispatcher to retarget
the event, consume it, dispatch the event itself, or make other changes.
Note that KeyboardFocusManager itself implements KeyEventDispatcher. By
default, the current KeyboardFocusManager will be the sink for all KeyEvents
not dispatched by the registered KeyEventDispatchers. The current
KeyboardFocusManager cannot be completely deregistered as a
KeyEventDispatcher. However, if a KeyEventDispatcher reports that it
dispatched the KeyEvent, regardless of whether it actually did so, the
KeyboardFocusManager will take no further action with regard to the
KeyEvent. (While it is possible for client code to register the current
KeyboardFocusManager as a KeyEventDispatcher one or more times, this is
usually unnecessary and not recommended.) |
| Methods Summary |
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| public boolean | dispatchKeyEvent(java.awt.event.KeyEvent e)This method is called by the current KeyboardFocusManager requesting
that this KeyEventDispatcher dispatch the specified event on its behalf.
This KeyEventDispatcher is free to retarget the event, consume it,
dispatch it itself, or make other changes. This capability is typically
used to deliver KeyEvents to Components other than the focus owner. This
can be useful when navigating children of non-focusable Windows in an
accessible environment, for example. Note that if a KeyEventDispatcher
dispatches the KeyEvent itself, it must use redispatchEvent
to prevent the current KeyboardFocusManager from recursively requesting
that this KeyEventDispatcher dispatch the event again.
If an implementation of this method returns false, then
the KeyEvent is passed to the next KeyEventDispatcher in the chain,
ending with the current KeyboardFocusManager. If an implementation
returns true, the KeyEvent is assumed to have been
dispatched (although this need not be the case), and the current
KeyboardFocusManager will take no further action with regard to the
KeyEvent. In such a case,
KeyboardFocusManager.dispatchEvent should return
true as well. If an implementation consumes the KeyEvent,
but returns false, the consumed event will still be passed
to the next KeyEventDispatcher in the chain. It is important for
developers to check whether the KeyEvent has been consumed before
dispatching it to a target. By default, the current KeyboardFocusManager
will not dispatch a consumed KeyEvent.
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