Here's the basic idea of the code I needed.
the touchMove event arrives in no particular order, and in no particular
time.
If you absolutely have to have a timeout, you can't just test for a
timestamp on the next run of touchMove, because there might not be
another touchMove.
I'm not quite clear on what the "wait 50 milliseconds with messages"
command does. Is that a more succinct way of putting it?
-Ken
-------------------8<-------------------------------
-- Semaphore handling for touch movements
--
-- This code is meant to be used to group random events that
-- happen in a timeframe, group them together, and take action
-- on those events as a whole.
--
-- User input is pseudo-random, and we therefore cannot count on
-- events coming in a particular order, or even coming at all.
--
-- I use code similar to this to group several distinct user inputs and
-- deal with several at a time. If no more events come within the
-- delay period, we fire the handler.
--
-- This isn't perfect, as there doesn't seem to be a way to cancel a
-- pending send...so we guard against the send happening in
-- performAction.
--
-- What this means is that the delay (50 milliseconds below) must
-- be chosen carefully so that there's only one group of data waiting
-- to be processed.
--
-- If the touchMove event happens but is delayed, and another
-- touchMove event with immediate execution happens within the
-- timeout period, the second touchMove event clears the sSemaphore,
-- so then the delayed performAction from the first touchMove event
-- is ignored.
--
local sDetails,sSemaphore
on touchMove pID,pX,pY
-- check to see if we've dealt with pID before
if pID is in the keys of sSemaphore then
-- have seen it before so take action immediately
put (pX&comma&pY) into sSemaphore[pID]
send "performAction "&pID&","&pX&","&pY
else
-- haven't seen it, only do it after a delay
put (pX&comma&pY) into sSemaphore[pID]
send "performAction "&pID&","&pX&","&pY to me in 50 milliseconds
end if
end touchMove
on performAction
-- check to see if it's already been handled.
if the number of lines in the keys of sSemaphore > 0 then
-- nope, let's get busy
-- code to deal with the data
delete variable sSemaphore
end if
end performAction
_______________________________________________
use-livecode mailing list
[email protected]
Please visit this url to subscribe, unsubscribe and manage your subscription
preferences:
http://lists.runrev.com/mailman/listinfo/use-livecode
