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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()
loader.load(request);
addChild(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
Working with application domains
and
Loading content
.
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.
There are a few differences for loading a SWF file in Adobe AIR
for iOS versus other platforms. For more information, see
Loading SWF files in AIR for iOS
.
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).
There
are important differences when loading an ActionScript 1.0 or 2.0
SWF file into an ActionScript 3.0 SWF file (compared to loading
an ActionScript 3.0 SWF file). Flash Player provides full backward
compatibility with previously published content. Any content that
runs in previous versions of Flash Player runs in Flash Player versions
that support ActionScript 3.0. However, the following limitations apply:
-
ActionScript 3.0 code can load a SWF file written in
ActionScript 1.0 or 2.0. When an ActionScript 1.0 or 2.0 SWF file
is successfully loaded, the loaded object (the
Loader.content
property)
is 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 cannot access the properties, methods, or
objects of the loaded AVM1Movie object.
-
SWF files written in ActionScript 1.0 or 2.0 cannot load
SWF files written in ActionScript 3.0. This means that SWF files
authored in Flash 8 or Flex Builder 1.5 or earlier versions cannot
load ActionScript 3.0 SWF files.
The only exception to this
rule is that an ActionScript 2.0 SWF file can replace itself with
an ActionScript 3.0 SWF file, as long as the ActionScript 2.0 SWF
file hasn't previously loaded anything into any of its levels. An
ActionScript 2.0 SWF file can do this through a call to
loadMovieNum()
,
passing a value of 0 to the
level
parameter.
-
In general, SWF files written in ActionScript 1.0 or 2.0
must be migrated if they are to work together with SWF files written
in ActionScript 3.0. For example, suppose you created a media player
using ActionScript 2.0. The media player loads various content that
was also created using ActionScript 2.0. You cannot create new content
in ActionScript 3.0 and load it in the media player. You must migrate
the video player to ActionScript 3.0.
If, however, you create
a media player in ActionScript 3.0, that media player can perform
simple loads of your ActionScript 2.0 content.
The following tables summarize the limitations of previous versions
of Flash Player in relation to loading newer content and executing
code, as well as the limitations for cross-scripting between SWF
files written in different versions of ActionScript.
|
Supported functionality
|
Flash Player 7
|
Flash Player 8
|
Flash Player 9 and 10
|
|
Can load SWFs published for
|
7 and earlier
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8 and earlier
|
9 (or 10) and earlier
|
|
Contains this AVM
|
AVM1
|
AVM1
|
AVM1 and AVM2
|
|
Runs SWFs written in ActionScript
|
1.0 and 2.0
|
1.0 and 2.0
|
1.0 and 2.0, and 3.0
|
In the following table, “Supported functionality” refers to content
running in Flash Player 9 or later. Content running in Flash Player
8 or earlier can load, display, execute, and cross-script only ActionScript
1.0 and 2.0.
|
Supported functionality
|
Content created in ActionScript 1.0 and
2.0
|
Content created in ActionScript 3.0
|
|
Can load content and execute code in content created
in
|
ActionScript 1.0 and 2.0 only
|
ActionScript 1.0 and 2.0, and ActionScript
3.0
|
|
Can cross script content created in
|
ActionScript 1.0 and 2.0 only (ActionScript
3.0 through Local Connection)
|
ActionScript 1.0 and 2.0 through LocalConnection.
ActionScript
3.0
|
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