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flex Loading an external SWF file

In ActionScript 3.0, SWF files are loaded using the Loader class. To load an external SWF file, your ActionScript needs to do four things:

Create a new URLRequest object with the url of the file.
Create a new Loader object.
Call the Loader object's load() method, passing the URLRequest instance as a parameter.
Call the addChild() method on a display object container (such as the main timeline of a Flash document) to add the Loader instance to the display list.
Ultimately, the code looks like this:

var request:URLRequest = new URLRequest("http://www.[yourdomain].com/externalSwf.swf");
var loader:Loader = new Loader()

This same code can be used to load an external image file such as a JPEG, GIF, or PNG image, by specifying the image file's url rather than a SWF file's url. A SWF file, unlike an image file, may contain ActionScript. Thus, although the process of loading a SWF file may be identical to loading an image, when loading an external SWF file both the SWF file doing the loading and the SWF file being loaded must reside in the same security sandbox if Flash Player or AIR is playing the SWF and you plan to use ActionScript to communicate in any way to the external SWF file. Additionally, if the external SWF file contains classes that share the same namespace as classes in the loading SWF file, you may need to create a new application domain for the loaded SWF file in order to avoid namespace conflicts. For more information on security and application domain considerations, see Using the ApplicationDomain class and Loading SWF files and images.

When the external SWF file is successfully loaded, it can be accessed through the Loader.content property. If the external SWF file is published for ActionScript 3.0, this will be either a movie clip or a sprite, depending on which class it extends.

Considerations for loading an older SWF file
If the external SWF file has been published with an older version of ActionScript, there are important limitations to consider. Unlike an ActionScript 3.0 SWF file that runs in AVM2 (ActionScript Virtual Machine 2), a SWF file published for ActionScript 1.0 or 2.0 runs in AVM1 (ActionScript Virtual Machine 1).

When an AVM1 SWF file is successfully loaded, the loaded object (the Loader.content property) will be an AVM1Movie object. An AVM1Movie instance is not the same as a MovieClip instance. It is a display object, but unlike a movie clip, it does not include timeline-related methods or properties. The parent AVM2 SWF file will not have access to the properties, methods, or objects of the loaded AVM1Movie object.

There are additional restrictions on an AVM1 SWF file loaded by an AVM2 SWF file. For details, see the AVM1Movie class listing in the ActionScript 3.0 Language and Components Reference.


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