Using Director > Parent Scripts > Using actorList |  |

Using actorList

Lingo can set up a special list of child objects (or any other objects) that receives its own message each time the playback head enters a frame or the `updateStage` command updates the Stage.

The special list is `actorList`, which contains only objects that have been explicitly added to the list. See `actorList`.

The message is the `stepFrame` message that is sent only when the playback head enters a frame or the `updateStage` command is used. See `on stepFrame`.

Objects in `actorList` receive a `stepFrame` message instead of an `enterFrame` message at each frame. If the objects have an `on stepFrame` handler available, the Lingo in the `on stepFrame` handler runs each time the playback head enters a new frame or the `updateStage` command updates the Stage.

Some possible uses of `the actorList` and `stepFrame` are to animate child objects that are used as sprites or to update a counter that tracks the number of times the playback head enters a frame.

An `on enterFrame` handler could achieve the same results, but the `actorList` property and `on stepFrame` handler are optimized for performance in Director. Objects in `the actorList` respond to `stepFrame` messages more efficiently than to an `enterFrame` message or to a custom message sent after an `updateStage` command.

To add an object to `actorList`, use the following statement:

    add the actorList, theObject

The object's `on stepFrame` handler in its parent or ancestor script will then run automatically each time the playback head advances. The object will be passed as the first argument (that is, the `me` argument) to the `on stepFrame` handler.

Director doesn't clear the contents of `actorList` when branching to another movie, which can cause unpredictable behavior in the new movie. If you don't want child objects in the current movie to be carried over into the new movie, insert a statement that clears `actorList` in the `on prepareMovie` handler of the new movie.

To clear child objects from `actorList`:

Set`actorList` to `[ ]`, which is an empty list.

For more information, see `actorList` and `on stepFrame`..