10 The Code. Part 2

From: zavpublic-spamblock-mac.com

Subject: Re: [DIRECT-L] Reusable UI framework code. The code. Part 2

Date: January 26, 2007 3:18:45 PM CST

To: DIRECT-L-spamblock-LISTSERV.UARK.EDU

Reply-To: DIRECT-L-spamblock-LISTSERV.UARK.EDU

Now, before we going with the code, there are a few final concepts of the structure that is about to follow:

Most importantly are the words spoken to Jason Chinn in 1998 when we were working on a site for Macromedia:

"The structure affords you the luxury to focus on the details."

And in that, understanding the structure and the "whys" behind it are also very important.

In this design, modularity and expandability is key. Therefore, in the script that determines the button has been clicked, when the click happens, it broadcasts a success message back to the button, which is caught by the scriptInstanceList of the button. Any script in that instanceList that contains a Success handler will be called.

Why is this cool?

This is great in terms of modularity. You do not have to cobble special condition code into already working code. You just create a behaviour for the task you desire the button to call. If you want a button to update a graph, then you have this type of code for your script:

-- Update Graph behaviour script

on Success

UpdateGraph

end

If the button's click would invoke more than one task, you can now organize your task execution more logically.

If the button would cause a user to Login and you have a "logged in user count" displayed somewhere, you can now do this:

-- Login and Update Display behaviour script

on Success

UpdateUserDisplay

end

Or, since these are two separate tasks, you can have the tasks separated in two behaviours which reside on the mask sprite's instanceList:

-- Login behaviour script

on Success

end

-- Update Display behaviour script

on Success

UpdateUserDisplay

end

The behaviour list for the mask sprite would look like so:

http://homepage.mac.com/zav/Scriptlist.jpg

Cool?

Now bear in mind that the "Button specific subclass - 1" script defines which sprites are the mask and the graphic sprites for the "4 state button script" which is forthcoming. It inherits this script and you have to do NOTHING AT ALL to make it work. I do believe that I've covered mostly everything that one would expect a button to do. If it does not do what you desire, the design is modular enough that other behaviours and classes can be added to accomplish this. Once we've got this lesson covered, we'll explore in that direction.

Final sprite, behaviour and cast structure is to be used as follows:

Sprite structure:

channel n + 0: Graphic sprite ("active" graphic, 32 bit alpha channeled bmp )

channel n + 1: Mask sprite (1 bit mask of "active" region)

Sprite Ink Settings

channel n + 0: copy, 100% blend

channel n + 1: matte, 0% blend

Cast Structure:

Member names for Graphic sprite members

myButtonName Active

myButtonName Rollover

myButtonName Down