Class: PluggableEventListener

• Inheritance
• Description
• Instance protocol
  • accessing
  • event processing

Inheritance:

   Object
   |
   +--EventListener
      |
      +--PluggableEventListener

Package:

stx:libview2

Category:

Interface-Support-UI

Version:

rev: 1.5 date: 2022/10/11 14:19:54

user: cg

file: PluggableEventListener.st directory: libview2

module: stx stc-classLibrary: libview2

Description:

a preliminary version of a pluggable event listener.
can be configured via handler blocks.

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.

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 openAndWaitUntilVisible.

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  

Instance protocol:

 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).

 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).

 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.