Mark Angeletti |
16 June 2006
Before we look at the code for frame 4, let's review. When
our Flash file loads, it hits frame 1 and sets all the
variables that we will need throughout our site. Next, in
frame 2, we gather external data. We got a little bonus and
learned how to import XML code which we then parsed and
stored in 3 arrays that we'll use in frame 4. In frame 3, we
imported the CSS that we'll use in frame 4.
What I want you to notice is that we're at our last frame
and, at this point, nothing has been built. Up to this point
we've only gathered the data that we'll need. We are now at
frame 4, where the playhead will rest indefinitely and our
Flash file will take form.
We start by tracing our arrays just to reassure ourselves
that we have everything we need. If you're not familiar with
the trace() function, then you won't get far in Flash.
Trace() is used to display messages in the Output panel
while testing your SWF file. Do a CTRL + ENTER right now and
it should pop up the Output panel, displaying the data from
- // make new MovieClip and
set to newly created button
- // load images
Recall that nTotalButtons was set in frame 2
and is equal to 4 -- the total number of buttons. Also
notice that navHolder_mc is already on our canvas in the
Now, we use a 'for loop' to create our 4 buttons. Within
navHolder_mc, we use the createEmptyMovieClip() method to
create a movie clip that will hold our buttons.
This creates a movie clip called navButton
and sets it equal to your newly created movie clip. This
just makes life easier: we can simply refer to navButton,
instead of navHolder_mc["navButton"+i], now.
We tell the loadClip() method to load the
button image (from our array) into the newly created movie
Now, remember that image_mcl was defined in frame 1 as a
MovieClipLoader, and MovieClipLoader allows us to implement
listener callbacks that let us know when our image has
The onLoadInit handler is invoked after the
actions in the first frame of the clip have executed, so you
can begin to manipulate the loaded clip. This handler is
called after the onLoadComplete handler. For most purposes,
use the onLoadInit handler.
At this point, we have a new movie clip for our button with
our image loaded into it. Now let's set some properties.
This attaches a variable called 'linkURL' to
target_mc movie clip; target_mc is automagically set to the
object that called this function; in this case it's our
movie clip button. Don't believe me? Trace it!
Note: 'Automagically' is a technical term for when something
happens automatically without you doing anything and you
can't really explain how it happens! Feel free to use it
around the office -- it will catch on.
Next, we set linkURL equal to the first link in our array.
This attaches the onPress event handler to
our button. In other words, when the button is clicked, it
will call the buttonClick function.
We define a couple of variables: one stores
our button's height, while the other stores its width.