Path: utzoo!attcan!uunet!bu.edu!snorkelwacker!apple!apple.com!rmh
From: rmh@apple.com (Rick Holzgrafe)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Misc Easy HC Questions
Message-ID: <10179@goofy.Apple.COM>
Date: 12 Sep 90 19:37:19 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 68
References:<11792@crdgw1.crd.ge.com> <10164@goofy.Apple.COM>

In article <10164@goofy.Apple.COM> Griffiths.R@AppleLink.Apple.com (Rob 
Griffiths) writes:
> on mouseup
>   put the ticks into TM
>   repeat until the mouseclick
>     if (the ticks - TM) > 20 then
>       -- too much time has transpired, cancel the handler.
>       -- or, alternatively, perform a single-click action.
>       -- (vary the double-click response speed by changing the "20"
>       -- to another number, either higher or lower.)
>       exit mouseup
>     end if
>   end repeat
>   -- if we get here, user has double clicked
>   -- so, put double-click action here!
> end mouseup
> 
> Just attach this to the object you wish to check, and add the code to 
> perform whatever actions you desire. One nice side benefit is that you 
> can make a single click perform one action (for instance, display a 
menu), 
> and a double click another (go directly to some card).

Just a friendly warning... the Apple Thought Police will getcha if you 
break a basic rule about clicking: NEVER WAIT FOR THE SECOND CLICK. You 
should do something immediately when you receive the first click, then 
something in addition when you receive the second. That way response to 
every click can be as fast as possible. The handler above, on the other 
hand, twiddles its thumbs while waiting for further orders from the user. 
(I know that HyperCard is slow enough that the difference may not be so 
noticable. But Macs are getting faster, and HC 2.0 is supposed to really 
zip along. And nobody likes to wait!)

Instead, I'd suggest something like the following, placed in the script of 
your stack. (Forgive any syntax errors, this is typed on the fly.)

function isDoubleClick
  global lastClickTime, lastClickItem
  put the ticks into TM
  if TM - lastClickTime < 20 and the id of the target is lastClickItem then
    return true
  else
    put TM into lastClickTime
    put the id of the target into lastClickItem
    return false
  end if
end isDoubleClick

Then do something like this in the script of each double-clickable item:

on mouseup
  if isDoubleClick then
    -- do double-click stuff
  else
    -- do single-click stuff
  end if
end mouseUp

Now, don't flame me about any of this - I don't work for the ATP. I just 
don't like seeing people dragged screaming from their beds in the middle 
of the night. :-) :-) :-)
 
==========================================================================
Rick Holzgrafe              |    {sun,voder,nsc,mtxinu,dual}!apple!rmh
Software Engineer           | AppleLink HOLZGRAFE1          rmh@apple.com
Apple Computer, Inc.        |  "All opinions expressed are mine, and do
20525 Mariani Ave. MS: 3-PK |    not necessarily represent those of my
Cupertino, CA 95014         |        employer, Apple Computer Inc."