[jawsscripts] Re: An interesting scripting problem
- From: Doug Lee <doug.lee@xxxxxxxxxxxxxxxx>
- To: jawsscripts@xxxxxxxxxxxxx
- Date: Sun, 6 May 2012 19:30:28 -0400
My normal way to handle that, at least when looping through windows,
is to stop if the window handle I get back is null. In this script,
you can do that by changing the While line to read
while x && hWin1
This works because hWin1, when treated as a boolean value like that,
will return True if non-empty and False when empty; and
getNextWindow() returns null when it runs out of windows.
If you do get stuck in an infinite loop in a modern JAWS version
though, you can escape it and shut down JAWS by typing
Insert+Windows+F4.
On Sun, May 06, 2012 at 07:14:42PM -0400, Andrew Hart wrote:
Correct me if I am wrong, but the while loop in this code makes me
nervous as it seems rather dangerous. The only way in which it can
terminate is if a window with the desired control id is found.
If the loop runs out of sibling windows to search, hWin1 and hWin2 will
end up with the value 0, but x will never get set to False.
In that case, the script will continue looping for ever, thus hanging JAWS.
If the window is guaranteed to exist, this is ok, but it would be good
coding practice to include another loop termination condition as a
safety net in case the application decides to behave badly or a future
update to the application removes the guarantee that the window is
always in the expected place. The termination condition could be a
simple counter to prevent the while loop iterating more than some
limited number of times that is considered reasonable (e.g. 10 or 20
iterations would probably suffice).
Btw, if anything were to go wrong and the script failed to locate a
window with the desired control id, the only way to recover from the
infinite loop would be to punch the off button on the machine. I have
managed to drop JAWS into infinite loops on numerous occasions (due to
an error in programming logic) and the result is not pretty and
definitely an occasion for slapping one's forehead and thinking "idiot!"
Every time I do this I feel like that bowl of petunias in Douglas
Adam's the Hitch-Hiker's Guide to the Galaxy: "Oh no, not again."
Hth,
Andrew.
On 6/05/2012 5:30 PM, Steve Matzura wrote:
> An interesting take. Problem is, if the window isn't there, what kind
> of error will I get back from the calling line?
>
> Anyway, I did solve the problem, and here's the script for it. Sorry
> about the bad line-wrapping.
>
> include "hjconst.jsh"
>
> Script FocusSearchList ()
>
> ; This script, attached to CTRL+Shift+L, ensures
> ; PC cursor is on a particular control before doing anything else.
>
> var handle hWin1, handle hWin2,
> int x
>
> let hWin1 = GetCurrentWindow ()
> if GetControlID (hWin1) != 1001
> then
> SayMessage (ot_jaws_message, "Place the PC Cursor on
> the search edit field before executing this script.", "PC Cursor to
> search field first.")
> return
> endif
>
> let hWin1 = GetParent(hWin1) ; Go up one level.
> let x = TRUE
>
> while x
>
> let hWin2 = GetNextWindow (hWin1) ; Go right one window.
> if GetControlID (hWin2) == 1019 ; Window not accessible via normal tab
> ; controls
> then
> SetFocus (hWin2) ; Force the PC Cursor to that window.
> let x = FALSE ; Terminate the while condition.
> else
> let hWin1 = hWin2
> ; Save the current window handle for the next go-round.
>
> Endif
>
> EndWhile
>
> ; Script should always find the window with control ID 1019 this way.
> ; Question: What value would hWin2 have if it got to the
> ;rightmost window and couldn't find the one with control ID 1019?
>
> EndScript
>
>
> On Sun, 6 May 2012 08:05:10 -0700, you wrote:
>
>> You can use the function IsWindowVisible()
>> That will tell you if it is present or visible rather.
>> John
>> -----Original Message-----
>> From: jawsscripts-bounce@xxxxxxxxxxxxx
>> [mailto:jawsscripts-bounce@xxxxxxxxxxxxx] On Behalf Of Steve Matzura
>> Sent: Sunday, May 06, 2012 7:34 AM
>> To: jawsscripts
>> Subject: [jawsscripts] An interesting scripting problem
>>
>> I'm scripting an application that has a window that's sometimes there,
>> sometimes not. The first order of business is to check if the window is
>> there, and if it is, set focus to it. I know the control ID of the window,
>> 1019. I'm trying to use FindDescendantWindow with a start handle of 0 to
>> verify its existence. My script so far looks like this:
>>
>> Script ReadSearchStatus ()
>>
>> var handle hwin
>>
>> let hwin = FindDescendantWindow (0, 1019)
>>
>> if hwin > 0
>> then
>> Say ("search window present.", ot_jaws_message, false)
>>
>> ; Insert code to set focus to the window. Should I even bother ; with this?
>> ; Should I just try setting focus and if it fails, assume the window's ; not
>> present?
>>
>> else
>> Say ("search window is not present.", ot_jaws_message, false)
>>
>> endif
>>
>> EndScript
>>
>> The problem is, it always comes up saying the window is present, even when
>> it's not.
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--
Doug Lee, Senior Accessibility Programmer
SSB BART Group - Accessibility-on-Demand
mailto:doug.lee@xxxxxxxxxxxxxxxx http://www.ssbbartgroup.com
"While they were saying among themselves it cannot be done,
it was done." --Helen Keller
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