Changes to the Macromedia Flash Asset Xtra in Director MX 2004

Direct Access to Macromedia Flash Object And Movie Clip References

Director MX introduced the ability to obtain an object reference to objects and/or movie clips with a Macromedia Flash sprite. This was a huge step forward in terms of programmatic access and control of Flash assets within Director. The process involved two steps:

1. Obtaining a reference to desired object reference using getVariable()
2. Calling a method or setting a supported property on that object

This was a major advancement, but it did have its difficulties since the getVariable method was really an overloaded version of the original getVariable() method introduced with the Flash 4 Asset Xtra. Flash 4 and 5 assets used getVariable()to get the string representation of an object or variable. Director MX added an optional parameter to indicate whether to retrieve the string representation "true" or the object reference "false." It was easy to forget the optional parameter or to use the incorrect one and get a string representation as opposed to the object reference. You can still use the getVariable metho as shown in this getVariable() example:

Lingo:

strValue = sprite(flashSpriteNum).getVariable("myObject")
strValue = sprite(flashSpriteNum).getVariable("myObject", true)
foObject = sprite(flashSpriteNum).getVariable("myObject", false)

JavaScript Syntax:

var strValue = sprite(flashSpriteNum).getVariable("myObject");
var strValue = sprite(flashSpriteNum).getVariable("myObject", true);
var foObject = sprite(flashSpriteNum).getVariable("myObject", false);

The first two examples return a string representation of a variable in Macromedia Flash, while the final example returns an object reference, which you can use to call methods and properties on the object.

Director MX 2004 simplifies this process by eliminating the getVariable() middle man, letting you directly access and manipulate Macromedia Flash objects and movie clips. In essence, access is almost identical to the way you would access and manipulate the same object types in ActionScript. The following examples demonstrate direct access to objects within a Flash sprite.

Lingo:

foObject = sprite(flashSpriteNum).myObject
foObject.someMethod()
foObject.someProperty = 23 

sprite(flashSpriteNum).myObject.someMethod()
sprite(flashSpriteNum).myObject.someProperty = 23

JavaScript Syntax:

var foObject = sprite(flashSpriteNum).myObject;
foObject.someMethod();
foObject.someProperty = 23; 

sprite(flashSpriteNum).myObject.someMethod();
sprite(flashSpriteNum).myObject.someProperty = 23;

While this may seem like a minor change, it provides a great deal of flexibility. You can manipulate a Macromedia Flash sprite going through the step-by-step process of first obtaining a reference using getVariable.

In addition to manipulating pre-existing objects in Macromedia Flash SWFs, you can create new instances of objects for native Flash data types and classes, as well as those that you have defined using the Director newObject method. There are two ways to use the newObject method; the first is to call newObject without a sprite reference. This creates a new Flash object reference that is associated with a special code-only instance of the Flash asset. Object types are restricted to only the built-in object types from Flash. The other method is to use the newObject method with a sprite reference. This method lets you instantiate both native Flash object types as well as user-defined classes on the _global object of Flash. The following are a few examples of using the newObject method:

Lingo:

xmlObject = newObject("XML", someXMLString)
xmlObject = sprite(flashSpriteNum).newObject("XML", someXMLString)

JavaScript Syntax:

var xmlObject = newObject("XML", someXMLString);
var xmlObject = sprite(flashSpriteNum).newObject("XML", someXMLString);

Note that if you intend to pass a Macromedia Flash object reference back into a Flash sprite as an object reference, you should create that object reference using the spriteRef.newObject() format. If you intend to only use the Flash object outside of a Flash sprite, then using the newObject() syntax without the Flash sprite reference is the way to go. However, if you have a Flash sprite on the Stage that will remain in scope for the duration of your need for the Flash object, then you should use the spriteRef.newObject() format. This is because the global code-only instance of the Flash asset is created when the first newObject method is called upon it. This has the same memory requirements as a separate instance of the Flash asset. Therefore, it is cheaper performance-wise to use the sprite reference method.

Page 5 of 8

Previous Page

Next Page