Lingo Dictionary > S > on stepFrame |  |

on stepFrame

Syntax

    on stepFrame
    	statement(s)
    end

Description

System message and event handler; works in script instances in `actorList` because these are the only objects that receive `on stepFrame` messages. This event handler is executed when the playback head enters a frame or the Stage is updated.

An `on stepFrame` handler is a useful location for Lingo that you want to run frequently for a specific set of objects. Assign the objects to `actorList` when you want Lingo in the `on stepFrame` handler to run; remove the objects from `actorList` to prevent Lingo from running. While the objects are in `actorList`, the objects' `on stepFrame` handlers run each time the playback head enters a frame or the `updateStage` command is issued.

The `stepFrame` message is sent before the `prepareFrame` message.

Assign objects to `actorList` so they respond to `stepFrame` messages. Objects must have an `on stepFrame` handler to use this built-in functionality with `actorList`.

The `go`, `play`, and `updateStage` commands are disabled in an `on stepFrame` handler.

Example

If the child object is assigned to `actorList`, the `on stepFrame` handler in this parent script updates the position of the sprite that is stored in the `mySprite` property each time the playback head enters a frame:

    property mySprite

    on new me, theSprite
    	mySprite = theSprite
    	return me
    end

    on stepFrame me
    	sprite(mySprite).loc = point(random(640),random(480))
    end