I think Mark did a great job of explaining it here. The key is that
QT behavior just broadcasts a message about the percentage completion
of the QT movie, and the receiver (the slider behavior) does whatever
it needs to do to represent that amount of completion. The slider
behavior could be a slider that updates based on 100 step increments,
it could be a series of 10 buttons where each one lights up at every
10 percent, it could be a vertical bar or horizontal bar, it could be
a circle that fills like a radar screen.
The point is that the interface between the sender and the receiver
is agreed upon in the syntax of the message, for example, a method
called: mHandlePercentPlayed(somePercentage). The sender doesn't
care what the receiver does when it receives the message, and the
receiver doesn't care what the sender had to do to generate the
message. As Mark said, this makes debugging much easier because you
can develop these two pieces independently from each other. You can
make changes to either one, and as long as they continue to use the
same message, the system will continue to work.
And yes, I think you've got it about the accessor methods, the
author's basic claim is that methods that get or set properties
directly are a bad thing. Again, I think this is an excellent design
goal.
Irv
At 8:51 PM -0600 8/20/01, Mark R. Jonkman wrote:
>
>
>I haven't followed this thread in its entirety... too busy.
>However, I think you can look at a little differently Al.
>You could have seperate objects that take care of the qt,
>the slider thumb and each other control. The messages don't
>necessarily need to be get and set directly. Your QT object
>could tell the slider what percent is currently played. It
>would be up to the slider object to call the necessary code
>to update its position with the positional information
>supplied by the call from the QT object and vice versa. Your
>not directly setting anything but rather responding to an
>outside "stimulus". The stimulus being the message from the
>QT object that it is has played 60%, the slider or other
>controls can respond to the message appropriately. In the
>same way, the slider could tell the qt object that someone
>has reset its position to say 30% played, its entirely up to
>the QT object to interpret that message and respond
>accordingly.
>
--
Lingo / Director / Shockwave development for all occasions.
(Home-made Lingo cooked up fresh every day just for you.)
[To remove yourself from this list, or to change to digest mode, go to
http://www.penworks.com/LUJ/lingo-l.cgi To post messages to the list,
email [EMAIL PROTECTED] (Problems, email [EMAIL PROTECTED])
Lingo-L is for learning and helping with programming Lingo. Thanks!]
