| Objects and Widgets [message #19933] |
Tue, 09 May 2000 00:00  |
Mark Guagenti
Messages: 14
Registered: May 2000
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Junior Member |
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I am trying to learn how to use objects and widgets together and I have
ran across a question for all of you. When I am creating a widget button
such as:
openID = Widget_Button(fileID, Value='Open...', Event_Pro='XPU_RI_Open')
Do I have to make a procedure XPU_RI_Open such as:
PRO XPU_RI_Open, event
Widget_Control, event.top, Get_UValue=info, /No_Copy
info.obj->open
Widget_Control, event.top, Set_UValue=info, /No_Copy
END
How come you can't call the object method directly from Event_Pro? Since
I will be using a lot of methods will I always have to make a procedures
to call them? Thanks for the help.
-- Mark
Grace and peace to you from God our Father and the Lord Jesus Christ.
1 Cor. 1:3
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| Re: objects and widgets [message #49222 is a reply to message #19933] |
Thu, 06 July 2006 07:36  |
larkn10
Messages: 10
Registered: July 2006
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Junior Member |
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Another thing you can do is something like the following:
;GET ALL VALID OBJECTS
ov = obj_valid()
;COUNT THE INSTANCES OF YOUR CLASS
className = 'TheNameOfYourClass'
count = 0
for i=0,n_elements(ov)-1 do begin
if obj_isa(ov[i],className) gt 0 then count++
endfor;i
print,count
;IF YOU WANT THE OBJECT REFERENCE(S)
if count gt 0 then begin
ref = obj_arr(count)
for i=0,n_elements(ov)-1 do begin
if obj_isa(ov[i],className) gt 0 then ref = ov[i]
endfor;i
endif
This would retrieve all subclasses of the class you are
interested in, so you might want to do something more to
search for the specific class you need.
You probably wouldn't want to do this in a program, but
it could be useful at times.
-Larry
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| Re: objects and widgets [message #49235 is a reply to message #19933] |
Wed, 05 July 2006 07:15 |
Michael Galloy
Messages: 1114
Registered: April 2006
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Senior Member |
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gnarloo@libero.it wrote:
> Dear all, I havent been around for pretty a long time, anyway, hope you
> all are doing fine.
> Imagine a program with a gui interface and callback procedures.
> i am writing the callback procedures, (basically the core of the
> program) but one thing occurs. I am using objects (self made, i wrote
> structures and methods) and i create them with obj_new at the '
> beginning' of my program, that is, i create the objects in the realize
> callback procedure of the base_0 widget. when I try to use the objects
> i have created in another unit program, for example a mouse button
> procedure, the object appears as undefined. I know for sure that the
> object was created but it appears that it doesnt have global scope. can
> anyone help? thanx to all in advance.
>
> cheers,
> Michele
>
Check out this article for one example of doing this:
http://michaelgalloy.com/2006/06/14/object-widgets.html
Mike
--
www.michaelgalloy.com
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| Re: objects and widgets [message #49236 is a reply to message #19933] |
Wed, 05 July 2006 06:21 |
btt
Messages: 345
Registered: December 2000
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Senior Member |
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gnarloo@libero.it wrote:
> Dear all, I havent been around for pretty a long time, anyway, hope you
> all are doing fine.
> Imagine a program with a gui interface and callback procedures.
> i am writing the callback procedures, (basically the core of the
> program) but one thing occurs. I am using objects (self made, i wrote
> structures and methods) and i create them with obj_new at the '
> beginning' of my program, that is, i create the objects in the realize
> callback procedure of the base_0 widget. when I try to use the objects
> i have created in another unit program, for example a mouse button
> procedure, the object appears as undefined. I know for sure that the
> object was created but it appears that it doesnt have global scope. can
> anyone help? thanx to all in advance.
>
Hi,
While objects are persistent heap variables they really don't have the
global scope you re assuming they do. You still have to tuck a reference
to the object somewhere handy in you program. Your best bet is to store
a reference to your objects in the UVALUE of the widget generating the
event. I like to store both the object reference and the method that I
want to call when the event occurs.
myWidgetID = WIDGET_SOMETHING(parent, ...., $
UVALUE = {OBJECT:myObjectReference, METHOD: "MethodForHandlingEvent"})
In the event callback access the the UVALUE that contains the reference
using (very simple example) ....
PRO MYEVENT, ev
WIDGET_CONTROL, ev.ID, get_Uvalue = myInfo
CALL_METHOD, myInfo.method, myInfo.object, ev
END
On the ATTVIS user contribution website there are some generic
object-associated event handlers written by Jim Pendelton that give you
more details. As always, check out David Fanning's very detailed
resources on this subject.
Cheers,
Ben
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