Re: [platform-ui-dev] Change in the ordering of key events from Eclipse

[Randy Hudson <hudsonr@xxxxxxxxxx>]

Michael,

Are you just trying to get the value
of a Text control on keydown?  Use a modify listener instead of a
key listener.
See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=47854
See the 3.0 porting guide also:
http://dev.eclipse.org/viewcvs/index.cgi/~checkout~/org.eclipse.platform.doc.isv/porting/incompatibilities.html#Key
down events

-Randy Hudson

Michael Elder/Cambridge/IBM@IBMUS Sent by: platform-ui-dev-admin@xxxxxxxxxxx 06/23/2004 10:11 AM Please respond to platform-ui-dev

To:        platform-ui-dev@xxxxxxxxxxx         cc:                 Subject:        [platform-ui-dev] Change in the ordering of key events from Eclipse 2.1.x to Eclipse 3.0

Hello all, 

        I've seen a problem in areas of our text widget
listeners which are handling some important events, and I've tracked the
problem down to a difference in the ordering of the events from Eclipse
2.1.x to Eclipse 3.0 which is caused by a difference in implementation
from Control.sendKeyEvent(int, int, int, int, Event). I am requesting information
about why the following change was made and how we should react to it.

In Eclipse 2.1.x we have: 

boolean sendKeyEvent (int type, int msg, int wParam, int lParam, Event
event) { 
        postEvent (type, event);
        return true; 
} 

But in Eclipse 3.0 we have: 

boolean sendKeyEvent (int type, int msg, int wParam, int lParam, Event
event) { 
        sendEvent (type, event);
        // widget could be disposed at this point
        
        /* 
        * It is possible (but unlikely), that application
        * code could have disposed the widget in the
key 
        * events.  If this happens, end the processing
of 
        * the key by returning false.
        */ 
        if (isDisposed ()) return false;
        return event.doit; 
} 

postEvent() and sendEvent() both call out to Widget.sendKeyEvent(int, Event,
boolean) [below] but vary the value of the boolean at the end of the method.

void sendEvent (int eventType, Event event, boolean send) {
        Display display = getDisplay ();
        if (eventTable == null && !display.filters
(eventType)) { 
                return;
        } 
        if (event == null) event = new Event ();
        event.type = eventType;
        event.display = display;
        event.widget = this; 
        if (event.time == 0) {
                event.time = display.getLastEventTime
(); 
        } 
        if (send) { 
                sendEvent (event);
        } else { 
                display.postEvent
(event); 
        } 
} 

The lines in this method were put in the CVS repo by Steve Northover (steve_northover@xxxxxxxxxx)
in early June 2003 in org.eclipse.swt.widgets/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
versions 1.134 and 1.137 on 06/05/2003 and 06/13/2003 respectively. They
list defects 25257 and 38841 in their comments. 

These were: 

Bug 25257 [Key Bindings] Cannot associate a key binding with a dialog -->
associated with the first line of the method 
Bug 38841 NPE in Widget.filters ---> this is associated with the remaining
lines 

Bug 25257 seems to be where the semantic change occurred. I have copied
the text of the defect comments below. Nothing seems obvious why they would
have made this change. My first run through the method I thought it was
doing the same thing as well (it was only a "little" boolean
on the end that was different ...). I'm curious if the change was made
originally trying to clean up the call, since postEvent() did and still
does delegate the method through to sendEvent() --> " void postEvent
(int eventType, Event event) { sendEvent (eventType, event, false); } "

20021022

I would like to have the copy functionality on the MultiErrorDialog but
I need 
API to register the widget (a list) with the copy action.

------- Additional Comment #1
From Chris
McLaren 2002-12-02 14:08 ------- 
You should not need special API outside the key binding service.

SWT's accelerator implementation doesn't allow the key binding service
to 
define accelerators on dialogs.

Moving to SWT and upgrading to critical. 

------- Additional Comment #2
From Christophe
Cornu 2002-12-03 09:23 ------- 
SN to investigate and advise 

------- Additional Comment #3
From Veronika
Irvine 2003-01-24 10:08 ------- 
Steve,  This is marked critical.  Please investigate and adjust
severity/prioerity accordingly. 

------- Additional Comment #4
From Tod
Creasey 2003-01-24 11:13 ------- 
FYI we have a workaround for this case currently in place for 2.1

------- Additional Comment #5
From Steve
Northover 2003-10-01 10:05 ------- 
There is not plan to implement an accelerator service that is independent
of 
the menu bar.  With the advent of Display.addFilter() and recent changes
to 
SWT.KeyDown, programmers who insist on defining an accelerator mechanism
that 
is non-standard can do so. 


Can anyone offer any information about this change and more importantly
how we should react to it? The listener we have attached to the widgets
should not be notified until *after* the change hits the widget. Right
now, we are notified about the widget *before* the value of the widget
changes. 

Thank you for your time in advance. 


-------------------------------------------------------------------------
Kind Regards,

Michael D. Elder
Rational Studio / J2EE Tools Development     
IBM RTP Lab
Ext: (919) 543-8356
T/L:  441-8356
mdelder@xxxxxxxxxx