Tài liệu Controlling a Movie on a Level ppt

We'll look at both approaches in the following exercise, in which we'll script our banner movies to reposition themselves correctly upon loading, as well as create a banner On/Off button

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Controlling a Movie on a Level

You can control a movie loaded into a level from another timeline or from within the movie itself The target path to a movie loaded into a level is simply its level number For example, if you've loaded a movie into level 5, you would use the following syntax to make it rotate from any other timeline currently in the player window:

_level5._rotation = 45;

Straightforward and simple It's also easy to place an action on Frame 1 of a loaded

movie so that it takes some action immediately upon loading We'll look at both

approaches in the following exercise, in which we'll script our banner movies to

reposition themselves correctly upon loading, as well as create a banner On/Off button

1 Open virtualaquarium5.fla

We'll continue working with this file from the preceding exercise The white rectangle on the stage is a movie clip instance named bannerBack_mc The

location of this instance's registration point (upper-left corner of the instance) will

be pivotal in a script that repositions the banner movies when they're loaded into Level 1 Because this repositioning script will reside within the banner movies, we need to open the banner movie's authoring files

2 Choose File > Open Navigate to the Lesson18/Assets folder, locate the file named banner0.fla, and open it in Flash

This simple animated movie is made up of five layers, the top of which is named Actions We'll place a two-line script on Frame 1 so that as soon as the banner

movie is loaded, the script is executed

3 With the Actions panel open, select Frame 1 of the Actions layer and add the following script:

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5 _x = _level0.bannerBack_mc._x;

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7 _y = _level0.bannerBack_mc._y;

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These two lines of script set the x and y properties of this movie to match the x and y properties of the bannerBack_mc movie clip instance on Level 0 This technique causes the banner movie to load exactly on top of the bannerBack_mc

instance, even if bannerBack_mc is eventually moved from its current location

4 Add the script from Step 3 to Frame 1 of the other banner movies (banner1.fla and

banner2.fla); then re-export the three movies as banner0.swf, banner1.swf, and

banner2.swf, respectively

5 Return to virtualaquarium5.fla Choose Control > Test Movie

Again, a random banner is loaded; however, this time it loads at the proper

location If you wait 10 seconds, a different banner may load, also at the proper location in relation to bannerBack_mc

This is the best approach for triggering an action to occur as soon as the movie

loads

6 Close the test movie to return to the authoring file (virtualaquarium5.fla)

The banner movie loaded into Level 1 can easily be controlled from this movie as

well We'll script a button to demonstrate this principle

7 With the Actions panel open, select Frame 1 of the Actions layer and add the following script at the end of the current script:

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9 bannerControl_btn.onRelease = function() {

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11 _level1._visible = !_level1._visible;

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13 bannerBack_mc._visible = !bannerBack_mc._visible;

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15 }

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This script adds an onRelease event handler to the bannerControl_btn instance This step creates a toggling functionality that makes both the banner movie loaded into Level 1 and the bannerBack_mc movie clip instance either visible or

invisible, depending on the current state of the instance when the instance is

clicked Using the NOT (!) operator provides a quick and easy way to reverse

Boolean values of any kind

8 Choose Control > Test Movie

Click the On/Off button several times to test its functionality Wait 10 seconds for the banner to change The button continues to work because it's set up to control

the movie loaded into Level 1 rather than a particular banner movie

9 Close the test movie Save the file as virtualaquarium6.fla

This step completes the exercise We'll continue to build on this file in the

following exercises

It's important to note that security issues can arise when loading files from

different domains into a single player window (the Flash player considers a

subdomain as a different domain) There are a few restrictions to keep in mind For example, if a movie at www.derekfranklin.com/derekMovie.swf is being played and contains an action to load a movie located at

www.electrotank.com/jobeMovie.swf into Level 5, these two movies initially won't be able to exchange data via ActionScript because they were loaded from different domains A permission setting for allowing movies loaded from different domains to access each other's data can be used to override this restriction In this scenario, if derekMovie.swf contains the following setting (placed on Frame 1):

System.security.allowDomain("www.electrotank.com")

then jobeMovie.swf (loaded from electrotank.com) will have access to the data in derekMovie.swf

If jobeMovie.swf contains this setting:

System.security.allowDomain("www.derekfranklin.com")

then derekMovie.swf (loaded from derekfranklin.com) will have access to the data

in jobeMovie.swf

To this point in the lesson, we've concentrated on loading and controlling

graphical content; however, a good Flash developer knows that graphics are just part of any great multimedia project You also need sound, but sound contributes significantly to file size, which means that smart sound management is key In the

next two exercises, we'll show you how to use audio efficiently in your projects

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