Testing if the mouse clicked on ME (button)?!

[H Baric]

Hi Jacqueline,

Bloomin terrifying. :-o

So, thanks very much for your encouragement, it really made me feel great!

I'm so flat out with my toddler most of the time, and wish I had more time 
to stay in "the Rev Zone". Or even keep up with all the posts daily phew!

I just want to thank everyone sooo much for your time and detailed help with 
every question I have :) especially for the last 10 or so replies to my last 
questions that I haven't yet followed up on. Hope I get to read them all and 
work on them tonight FINALLY after a few days of toddler hell!

Cheers,
Heather


----- Original Message ----- 
From: "J. Landman Gay" <jacque at hyperactivesw.com>
To: "How to use Revolution" <use-revolution at lists.runrev.com>
Sent: Sunday, August 10, 2008 4:31 AM
Subject: Re: Testing if the mouse clicked on ME (button)?!


H Baric wrote:

> Making a timer, with just one button and one field.
> The one button is to start and stop the timer.
> The button's label is changed to "Stop" when it starts, and "Start" when 
> it
> stops. I think I got that?
> But, how to test when the user clicks on the button during the process?
> (sorry, hey don't laugh! I have been searching and trying everything I 
> know,
> which isn't much yet!)

I'm just delighted you are posting here. I think this list can be scary
for newcomers and they don't always post. I wish we had more like you.
Please don't stop.

>
> But it's simple right? *blush*

It can be, but the easy way isn't the right way. First let's fix your
script to do it the easy way, and then I'll tell you why you shouldn't
use it.

> on mouseUp
>     if the label of me is "Start" then
>         set the label of me to "Stop"
>         repeat with tCount = 1 to 60
>         put tCount into fld "Counter Show"
>         wait 1 second

While this repeat is running, nothing else can happen. The 60-second
wait will block all other processes on the whole computer while the
repeat loop goes around and around. Other background programs will stop
whatever they are doing, the whole CPU will hang in limbo until that
minute is over. That's one reason why we don't do it this way. But let's
look at the script some more anyway.

>         if (I am clicked??) and the label of me is "Stop" then

The event you want here is "the mouseclick". When the user clicks, the
"mouseclick" event is sent to whatever object is clicked. So the correct
line is:

   if the mouseclick then

You don't need to check to see if the label is "stop" because the first
line of the "if" clause has already set that and it can't possibly be
anything else.

>             exit repeat
>             set the label of me to "Start"

When you exit the repeat, any remaining lines in the repeat loop will be
skipped and the handler will proceed to the line after the "end repeat".
That means the label here will never be set to "start" because the loop
has already exited. Change the order so that the "exit" is the last
thing that happens:

    set the label of me to "Start"
    exit repeat

So, here's the whole working script:

on mouseUp
     if the label of me is "Start" then
         set the label of me to "Stop"
         repeat with tCount = 1 to 60
          put tCount into fld "Counter Show"
          wait 1 second
          if the mouseclick then
             set the label of me to "Start"
             exit repeat
          end if
         end repeat
     end if
end mouseUp

That's the easy way, but don't do it. In addition to blocking the CPU
while this repeat loop runs, there's another reason to avoid this
technique. The "mouseclick" (or any other mouse events) are not reliable
when checked in a loop. The engine will only recognize a mouse event if
it occurs at the same moment the script is checking for it. In a very
short loop, it will probably "see" the mouse event most of the time. But
in very long scripts inside a repeat loop, another part of the handler
may be running when the mouse is clicked (like during the 1-second wait
above,) and the script won't be checking at that precise moment, so the
loop will not exit.

So a much better way to handle this kind of thing is to use the
techniques that Eric and others have pointed out. It's more complicated,
but it is more reliable and it doesn't block the CPU. There is more info
about this technique here:

<http://www.hyperactivesw.com/polling.html>

Thanks again for posting, I hope you inspire all our other new Revvers
to do the same.

-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com
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