ThrottleEvent

Package	flash.events
Class	public class ThrottleEvent
Inheritance	ThrottleEvent Event Object

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

A ThrottleEvent is dispatched when the Flash Player throttles, pauses, or resumes content. There is only one type of ThrottleEvent event: ThrottleEvent.THROTTLE.

This event is a broadcast event, which means that it is dispatched by all EventDispatcher objects with a listener registered for this event. For more information about broadcast events, see the DisplayObject class.

Note: This event has neither a "capture phase" nor a "bubble phase", which means that event listeners must be added directly to any potential targets, whether the target is on the display list or not.

The Flash Player can throttle the content to a low frame rate (meaning the frame rate is reduced to a value typically between 2 and 8 fps). Content can be throttled when its tab is hidden or minimized. On a mobile device, content can be throttled when the backlight goes off or screensaver mode comes on. Prior to throttling the content, a ThrottleEvent is dispatched with ThrottleEvent.state=ThrottleType.THROTTLE. The ThrottleEvent.targetFrameRate property contains the value of the new target frame rate.

The content can run code in the event listener to prepare for the throttle. This is an opportunity to alert external content that the throttled content is much less responsive. For instance, an active FileReference.upload() or FileReference.download() method could be canceled. Or, if content is communicating using LocalConnection with another SWF, this is an opportunity to inform that SWF to expect less responsiveness. Note that the throttled content may not be able to complete asynchronous actions prior to entering the throttle. Content enters the throttled state when the event listener returns.

The Flash Player can pause content. For example, content can be paused when it is scrolled offscreen on a mobile device at a time when no audio or video is playing. Prior to pausing the content, a ThrottleEvent is dispatched with ThrottleEvent.state=ThrottleType.PAUSE and ThrottleEvent.targetFrameRate=0. Similar to when the content receives a ThrottleType.THROTTLE event, the content can run code in the event listener to prepare for the pause. When the event listener returns, the content enters the paused state. While paused, the content does not respond to user interaction, such as mouse clicks or keyboard entry. However, ActionScript network events can still be received.

When the Flash Player resumes the content from a throttled or paused state, a ThrottleEvent is dispatched with ThrottleEvent.state=ThrottleType.RESUME. ThrottleEvent.targetFrameRate describes the frame rate and is normally equal to Stage.frameRate. Content may be resumed when any part of the stage becomes visible or when the user makes a request for the content to be resumed.

The platforms that support throttling and pausing are currently the following: Flash Player Desktop Mac and Windows, AIR Mobile, and Flash Player Android. The following platforms do not dispatch the ThrottleEvent automatically because they do not yet support pausing or throttling: AIR for TV devices, AIR for desktop, and Flash Player Linux Desktop.

Related API Elements

flash.display.DisplayObject
flash.display.Stage
flash.events.ThrottleType

Public Properties

	Property		Defined By
		bubbles : Boolean [read-only] Indicates whether an event is a bubbling event.	Event
		cancelable : Boolean [read-only] Indicates whether the behavior associated with the event can be prevented.	Event
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		currentTarget : Object [read-only] The object that is actively processing the Event object with an event listener.	Event
		eventPhase : uint [read-only] The current phase in the event flow.	Event
		state : String [read-only] Describes the state that the player is entering: ThrottleType.THROTTLE, ThrottleType.PAUSE, or ThrottleType.RESUME.	ThrottleEvent
		target : Object [read-only] The event target.	Event
		targetFrameRate : Number [read-only] The frame rate that Flash Player or AIR targets after the ThrottleEvent is dispatched.	ThrottleEvent
		type : String [read-only] The type of event.	Event

Public Methods

	Method		Defined By
		ThrottleEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false, state:String = null, targetFrameRate:Number = 0) Creates an Event object that contains information about the ThrottleEvent.	ThrottleEvent
		clone():Event [override] Creates a copy of the ThrottleEvent object and sets the value of each property to match that of the original.	ThrottleEvent
		formatToString(className:String, ... arguments):String A utility function for implementing the toString() method in custom ActionScript 3.0 Event classes.	Event
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isDefaultPrevented():Boolean Checks whether the preventDefault() method has been called on the event.	Event
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		preventDefault():void Cancels an event's default behavior if that behavior can be canceled.	Event
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		stopImmediatePropagation():void Prevents processing of any event listeners in the current node and any subsequent nodes in the event flow.	Event
		stopPropagation():void Prevents processing of any event listeners in nodes subsequent to the current node in the event flow.	Event
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String [override] Returns a string that contains all the properties of the ThrottleEvent object.	ThrottleEvent
		valueOf():Object Returns the primitive value of the specified object.	Object

Public Constants

	Constant		Defined By
		THROTTLE : String = "throttle" [static] Defines the value of the type property of a ThrottleEvent event object.	ThrottleEvent

Property Detail

state

property

state:String [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

Describes the state that the player is entering: ThrottleType.THROTTLE, ThrottleType.PAUSE, or ThrottleType.RESUME.

Implementation
public function get state():String

Related API Elements

flash.events.ThrottleType

targetFrameRate

property

targetFrameRate:Number [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

The frame rate that Flash Player or AIR targets after the ThrottleEvent is dispatched.

For example, if the content is being paused, targetFrameRate is 0. If the content is being throttled, then targetFrameRate is typically between 2 and 8, depending on which platform the content is running on, whether audio is playing, and other factors. If the content is returned to the expected frame rate after being paused or throttled, targetFrameRate equals Stage.frameRate.

Implementation
public function get targetFrameRate():Number

Related API Elements

flash.display.Stage

Constructor Detail

ThrottleEvent

()

Constructor

public function ThrottleEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false, state:String = null, targetFrameRate:Number = 0)

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

Creates an Event object that contains information about the ThrottleEvent. Event objects are passed as parameters to event listeners.

Parameters

	`type:String` — The type of the event. Event listeners can access this information through the inherited `type` property. There is only one type of ThrottleEvent event: `ThrottleEvent.THROTTLE`.

	`bubbles:Boolean` (default = `false`) — Determines whether the Event object participates in the bubbling stage of the event flow. Event listeners can access this information through the inherited `bubbles` property.

	`cancelable:Boolean` (default = `false`) — Determines whether the Event object can be canceled. Event listeners can access this information through the inherited `cancelable` property.

	`state:String` (default = `null`) — `ThrottleType.THROTTLE`, `ThrottleType.PAUSE`, or `ThrottleType.RESUME`.

	`targetFrameRate:Number` (default = `0`) — Describes the frame rate that Flash Player or AIR will target after the ThrottleEvent is dispatched. For example, if the content is being paused, `targetFrameRate` is 0. If the content is being throttled, then `targetFrameRate` is typically between 2 and 8, depending on which platform the content is running on, whether audio is playing, and other factors. If the content is returned to the expected frame rate after being paused or throttled, `targetFrameRate` equals `Stage.frameRate`.

Related API Elements

flash.display.Stage

Method Detail

clone

()

method

override public function clone():Event

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

Creates a copy of the ThrottleEvent object and sets the value of each property to match that of the original.

Returns

Event — A new ThrottleEvent object with property values that match those of the original.

toString

()

method

override public function toString():String

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

Returns a string that contains all the properties of the ThrottleEvent object. The string is in the following format:

[ThrottleEvent type=value bubbles=value cancelable=value state=value targetFrameRate=value]

Returns

String — A string that contains all the properties of the ThrottleEvent object.

Constant Detail

THROTTLE

Constant

public static const THROTTLE:String = "throttle"

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, AIR 3.2

Defines the value of the type property of a ThrottleEvent event object.

This event has the following properties:

Property	Value
`bubbles`	`false`
`cancelable`	`false`; there is no default behavior to cancel.
`currentTarget`	The object that is actively processing the Event object with an event listener.
`target`	Any DisplayObject instance with a listener registered for the throttle event.
`state`	ThrottleType.THROTTLE, ThrottleType.PAUSE, or ThrottleType.RESUME.
`targetFrameRate`	Describes the frame rate that Flash Player or AIR will target after the ThrottleEvent is dispatched. For example, if the content is being paused, targetFrameRate will be 0. If the content is being throttled, then targetFrameRate is typically between 2 and 8, depending on which platform the content is running on, whether audio is playing, and other factors. If the content is returned to the expected frame rate after being paused or throttled, targetFrameRate equals Stage.frameRate.

Related API Elements

flash.display.Stage

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ThrottleEvent - AS3

Classes x

state

targetFrameRate

ThrottleEvent

clone

toString

THROTTLE