undefinedobject showflag

I keep getting this message 'undefinedobject showflag', when working with the viewer for graphically objects and when saving the image.  This happens with Squeak 3.9 /7067.

Here's a screengrab (couldn't figure out how to capture the text contents)

http://mstram.freepgs.com/img/undefinedobject_showflag.jpg

Mike

[Newbies] undefinedobject showflag


Hi Mike,

Thanks for the picture.

nil is the one and only instance of Undefined object.

The error message says that nil does not understand
(has no method for)
the message "showflap".

The question is why is
aViewer owner ifNotNilDo: [ :f | ^f flapTab showFlap;
yourself ].

trying to send #showFlap to nil.


PasteUpMoprh>>flapTab
        | ww |
        self isFlap ifFalse:[^nil].
        ww _ self world ifNil: [World].
        ^ww flapTabs detect:[:any| any referent == self]
ifNone:[nil]

is returning nil so either "aViewer owner" is not a
flap or none of the worlds flapTabs are this one.

If you explore how to use the debugger you can
actually look to see which is the case.

Without knowing how to recreate the problem I couldn't
say from the outside. (First rule of troubleshooting
is first hand information.)  ;-)

However, one suggestion would be just abandon the
debug window. And then see if anything vital is
actually missing.  And maybe next time when saving a
project, dismiss the viewer flaps from the screen
before saving.

hth,

Yours in curiosity and service, --Jerome Peace



***
>mstram mstramba at sympatico.ca
>Thu May 24 21:41:47 UTC 2007 wrote:
>
>I keep getting this message 'undefinedobject
showflag', when working with the
>viewer for graphically objects and when saving the
image.  This happens with
>Squeak 3.9 /7067.
>
>Here's a screengrab (couldn't figure out how to
capture the text contents)
>
>http://mstram.freepgs.com/img/undefinedobject_showflag.jpg
>
>Mike
>--
***



       
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Jerome,

I think I may know what is causing the problem.

When I opened one or more viewers on objects I had added / painted, the flap that was created
to contain the viewers was bugging me so I alt-clicked it, and used the X-icon to delete it.

I see from looking at the debug/inspect owner chain that a viewer's owner/parent is normally the "viewer flap" (when the option "viewersInFlaps" is on.  

I just tried to recreate deleting the viewer-flap before deleting the viewer(s), but when I do it now, the viewers are being deleted as well (as they should be, I assume).  I'm almost sure I was somehow able to drag/move the viewer-flap at one point and the viewers were being "left behind".  If I deleted the flap at that point I'm guessing the viewers would be "orphaned" and that might be what is causing the problem.

Mike

P.S.  Can someone rename this thread to  " .... *showFLAP*"  instead of "FLAG" ... (stupid me) !

Some further experimentation :

1)Add a morph to the world.

2) open a viewer, (with the "viewersInFlaps" option on)

3) Open the halo for that viewer
4) Drag the viewer to the world (off the flap)

5) Select the morph again, open it's halo, (try) to open a viewer for it (with the other viewer still displayed) and the "undefinedObject>>ShowFlap error is displayed.

If the "dragged/disconnected (from the flap)" viewer is first deleted,  the error message doesn't appear.

Mike

Further findings.

If I delete all open viewers / flaps, the error message also goes away when saving the image !

Mike