| Re: widgets and objects [message #10185] |
Thu, 30 October 1997 00:00  |
savoie
Messages: 68
Registered: September 1996
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Member |
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NOTE: what follows is valid for idl 4 (I don't have 5 yet, so I can't
tell you if there's a better way to do this with pointers, I'd imagine
so)
> I am trying to figure out widgets and I don't know if what i am trying
> to do is even possible - maybe it's just the wrong way to go about it.
> I have an object, during the initialization of that object I have a
> widget come up that has some checkboxes and an OK button for the use to
> select some choices during initialization.
You want to launch a widget, and it's event handler before initialization.
> Where i am encountering problems is when i call xmanager is still
> continues with initialization. Do i even want to call xmanager? And
> how do i pass back the choices that the user chose?
Sounds like you might want a /modal widget (blocking), but if you're
only launching one small widget, it shouldn't matter.
Code before initialize
code that launches widget
code that initializes
> There doesn't seem to be an easy way to pass variables around with
> widget events. Is the only way to do this is by using UVALUE?
Matthew, you're very perceptive, there are no easy ways to pass
variables around in widgets. There are a few tricks with UVALUE, but
for what you want to do, it might be easiest to do something like
this.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;
;; make the event handler for the launched widget.
PRO example_event, event
;; get the data handle.
widget_control, event.top, get_uval=sdh
;; get the uval from the event.id
widget_control, event.id, get_uval=uv
CASE uv OF
'b1' : BEGIN
message_in_here = 'Button One was pressed: plan accordingly'
END
'b2' : BEGIN
message_in_here = 'Button Two was pressed: give up. '
END
'ok' : BEGIN
;; leave this mess
widget_control, event.top, /destroy
END
ELSE: message_in_here, 'something broke'
ENDCASE
;; if the widget still exists, store the data in the sdh(handle).
IF widget_info(event.top, /valid) then $
handle_value, sdh, message_in_here, /set
END
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;
pro example
;;; example on how to pass variables to widges
;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;
;;code to set up widgets
tlb = widget_base(/column)
but = widget_button(tlb, value='BUTTON 1', uval='b1')
but2 = widget_button(tlb, value='BUTTON 2', uval='b2')
ok = widget_button(tlb, value='OK', uval='ok')
widget_control, tlb, /realize
;; introduce the varaible into scope here
secret_data_handle = handle_create()
;; set it to the uval of the top level base (tlb)
widget_control, tlb, set_uvalue=secret_data_handle
;; use the /Modal keyword to keep from proceeding in this routine.
xmanager, 'example', tlb, event_handler='example_event', $
/modal
;; and here the scope is still valid here.
handle_value, secret_data_handle, what_was_there
print, 'the button last pushed before exiting gave this string:'
print, what_was_there
END ;; example
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;
> It looks as if you have to set UVALUE to some variable (structure,
> vari, or otherwise) and you can then retrieve and set it during the
> event procedure. But then how can i retrieve it later? When the
> widget comes up the initialization function finishes. Then the
> variables that hold the choices go out of scope and are inaccessible
> to any other procedure. Do i have this all wrong? -matt
I think the above example explains this pretty well.
Hope this helps.
Mattie
--
Matthew H. Savoie Systems Technology Associates
Systems Analyst Supporting NOAA Profiler Network
ph. 303.497.6642 Demonstration Division/FSL/ERL
mailto: savoie@fsl.noaa.gov <URL:http://www-dd.fsl.noaa.gov/online.html>
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