"

 COPYRIGHT (c) 2014 by Claus Gittinger

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libview2' }"

EventListener subclass:#PluggableEventListener

	instanceVariableNames:'keyPressAction keyReleaseAction'

	classVariableNames:''

	poolDictionaries:''

	category:'Interface-Support-UI'

!

!PluggableEventListener class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 2014 by Claus Gittinger

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    a preliminary version of a pluggable event listener.

    can be configured via handler blocks.

    [see also:]

        WindowSensor WindowEvent WindowGroup

    [author:]

        Claus Gittinger

"

!

example

"

    to eat a particular key from another view:

    |v e|

    v := StandardSystemView extent:300@200.

    v add:(e := EditTextView origin:0.0@0.0 corner:1.0@1.0).

    v label:'key a is ignored'.

    v openAndWait.

    e sensor addEventListener:(

        PluggableEventListener new

            keyPressAction:[:event |

                event key == $a ifTrue:[

                    Transcript showCR:'a key eaten'.

                    true.

                ] ifFalse:[

                    Transcript showCR:'other key ok:',event key printString.

                    false

                ]

            ]).

    to get events for a hotKey (attention: synchronous,

    so you better enqueue the event into an application's private queue

    in the handler block)

    Display rootView

        addHotKeyHandler:(

                PluggableEventListener new

                    keyPressAction:[:event |

                        Transcript showCR:event.

                        event key = 'F2' ifTrue:[

                            Transcript showCR:'F2 pressed'.

                            true.

                        ] ifFalse:[

                            Transcript showCR:'other key ok:',event key printString.

                            false

                        ]

                    ])

         forKey:'F2'

         modifierMask:nil  

"

! !

!PluggableEventListener methodsFor:'accessing'!

keyPressAction:aBlock

    "install a block as handler for keyPress events.    

     the block will get the windowEvent as argument,

     and is supposed to return true if it handled the event,

     false if not (so the event is processed as usual)."

    keyPressAction := aBlock.

!

keyReleaseAction:aBlock

    "install a block as handler for keyRelease events.    

     the block will get the windowEvent as argument,

     and is supposed to return true if it handled the event,

     false if not (so the event is processed as usual)."

    keyReleaseAction := aBlock.

! !

!PluggableEventListener methodsFor:'event processing'!

processEvent:anEvent

    "process an event; if true is returned, the event is considered to be

     'eaten' by the listener, and not passed to the view.

     If false is returned, the event is processed as usual.

     Here, the event is dispatched into one of the button*/key* etc. methods"

    |handler|

    anEvent isKeyPressEvent ifTrue:[

        handler := keyPressAction

    ] ifFalse:[

        anEvent isKeyReleaseEvent ifTrue:[

            handler := keyReleaseAction

        ]

    ].

    handler notNil ifTrue:[

        ^ handler value:anEvent

    ].

    ^ false

! !

!PluggableEventListener class methodsFor:'documentation'!

version

    ^ '$Header: /cvs/stx/stx/libview2/PluggableEventListener.st,v 1.2 2014-09-23 11:36:30 cg Exp $'

!

version_CVS

    ^ '$Header: /cvs/stx/stx/libview2/PluggableEventListener.st,v 1.2 2014-09-23 11:36:30 cg Exp $'

! !