mx.effects.TweenEffect - Adobe® Flex® 4 Language Reference (Flex 4)

Package	mx.effects
Class	public class TweenEffect
Inheritance	TweenEffect Effect EventDispatcher Object
Subclasses	AnimateProperty, Blur, Dissolve, Fade, Glow, Move, Pause, Resize, Rotate, SeriesEffect, Zoom

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Starting with Flex 4.0, Adobe recommends that you use the spark.effects.Animate class as an alternative to this class.

TweenEffect is the superclass for the animated effects in Flex 3. As of Flex 4, the Spark effects extend the spark.effects.Animate class instead of TweenEffect.

The TweenEffect class is the superclass for all effects that are based on the Tween object. This class encapsulates methods and properties that are common among all Tween-based effects, to avoid duplication of code elsewhere.

You create a subclass of the TweenEffect class to define an effect that plays an animation over a period of time. For example, the Resize effect modifies the size of its target over a specified duration.

MXML Syntax expanded

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The <mx:TweenEffect> tag inherits all of the tag attributes of its superclass, and adds the following tag attributes:

  <mx:TagName
    Properties
    easingFunction="easing function name; no default"
     
    Events
    tweenEnd="No default"
  />

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Public Properties

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	Property		Defined By
		className : String [read-only] The name of the effect class, such as "Fade".	Effect
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		customFilter : mx.effects:EffectTargetFilter Specifies a custom filter object, of type EffectTargetFilter, used by the effect to determine the targets on which to play the effect.	Effect
		duration : Number Duration of the effect in milliseconds.	Effect
		easingFunction : Function = null The easing function for the animation.	TweenEffect
		effectTargetHost : mx.effects:IEffectTargetHost A property that lets you access the target list-based control of a data effect.	Effect
		filter : String Specifies an algorithm for filtering targets for an effect.	Effect
		hideFocusRing : Boolean Determines whether the effect should hide the focus ring when starting the effect.	Effect
		instanceClass : Class An object of type Class that specifies the effect instance class class for this effect class.	Effect
		isPlaying : Boolean [read-only] A read-only flag which is true if any instances of the effect are currently playing, and false if none are.	Effect
		perElementOffset : Number Additional delay, in milliseconds, for effect targets after the first target of the effect.	Effect
		playheadTime : Number Current time position of the effect.	Effect
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		relevantProperties : Array An Array of property names to use when performing filtering.	Effect
		relevantStyles : Array An Array of style names to use when performing filtering.	Effect
		repeatCount : int = 1 Number of times to repeat the effect.	Effect
		repeatDelay : int = 0 Amount of time, in milliseconds, to wait before repeating the effect.	Effect
		startDelay : int = 0 Amount of time, in milliseconds, to wait before starting the effect.	Effect
		suspendBackgroundProcessing : Boolean = false If true, blocks all background processing while the effect is playing.	Effect
		target : Object The object to which this effect is applied.	Effect
		targets : Array An Array of objects that are targets for the effect.	Effect
		triggerEvent : Event The Event object passed to this Effect by the EffectManager when an effect is triggered, or null if the effect is not being played by the EffectManager.	Effect

Protected Properties

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	Property		Defined By
		applyTransitionEndProperties : Boolean This flag controls whether the effect, when run in a transition, automatically applies the property values according to the end state, as opposed to leaving values as set by the effect itself.	Effect
		endValuesCaptured : Boolean = false A flag containing true if the end values of an effect have already been determined, or false if they should be acquired from the current properties of the effect targets when the effect runs.	Effect

Public Methods

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	Method		Defined By
		TweenEffect(target:Object = null) Constructor.	TweenEffect
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		captureEndValues():void Captures the current values of the relevant properties on the effect's targets and saves them as end values.	Effect
		captureMoreStartValues(targets:Array):void Captures the current values of the relevant properties of an additional set of targets Flex uses this function when a data change effect is run.	Effect
		captureStartValues():void Captures the current values of the relevant properties on the effect's targets.	Effect
		createInstance(target:Object = null):IEffectInstance Creates a single effect instance and initializes it.	Effect
		createInstances(targets:Array = null):Array Takes an Array of target objects and invokes the createInstance() method on each target.	Effect
		deleteInstance(instance:IEffectInstance):void Removes event listeners from an instance and removes it from the list of instances.	Effect
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		end(effectInstance:IEffectInstance = null):void Interrupts an effect that is currently playing, and jumps immediately to the end of the effect.	Effect
		getAffectedProperties():Array Returns an Array of Strings, where each String is the name of a property changed by this effect.	Effect
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		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
		pause():void Pauses the effect until you call the resume() method.	Effect
		play(targets:Array = null, playReversedFromEnd:Boolean = false):Array Begins playing the effect.	Effect
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		resume():void Resumes the effect after it has been paused by a call to the pause() method.	Effect
		reverse():void Plays the effect in reverse, if the effect is currently playing, starting from the current position of the effect.	Effect
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		stop():void Stops the effect, leaving the effect targets in their current state.	Effect
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Protected Methods

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	Method		Defined By
		applyValueToTarget(target:Object, property:String, value:*, props:Object):void Used internally by the Effect infrastructure.	Effect
		effectEndHandler(event:EffectEvent):void Called when an effect instance has finished playing.	Effect
		effectStartHandler(event:EffectEvent):void This method is called when the effect instance starts playing.	Effect
		effectStopHandler(event:EffectEvent):void Called when an effect instance has stopped by a call to the stop() method.	Effect
		filterInstance(propChanges:Array, target:Object):Boolean Determines the logic for filtering out an effect instance.	Effect
		getValueFromTarget(target:Object, property:String):* Called by the captureStartValues() method to get the value of a property from the target.	Effect
		initInstance(instance:IEffectInstance):void Copies properties of the effect to the effect instance.	Effect
		tweenEventHandler(event:mx.events:TweenEvent):void Called when the TweenEffect dispatches a TweenEvent.	TweenEffect

Events

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	Summary	Defined By
activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher
effectEnd	Dispatched when one of the effect's instances finishes playing, either when the instance finishes playing or when the effect is interrupted by a call to the end() method.	Effect
effectStart	Dispatched when the effect starts playing.	Effect
effectStop	Dispatched when the effect has been stopped, which only occurs when the effect is interrupted by a call to the stop() method.	Effect
tweenEnd	Dispatched when the tween effect ends.	TweenEffect
tweenStart	Dispatched when the tween effect starts, which corresponds to the first call to the onTweenUpdate() method.	TweenEffect
tweenUpdate	Dispatched every time the tween effect updates the target.	TweenEffect

Property Detail

easingFunction

property

public var easingFunction:Function = null

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

The easing function for the animation. The easing function is used to interpolate between the initial value and the final value. A trivial easing function would simply do linear interpolation, but more sophisticated easing functions create the illusion of acceleration and deceleration, which makes the animation seem more natural.

If no easing function is specified, an easing function based on the Math.sin() method is used.

The easing function follows the function signature popularized by Robert Penner. The function accepts four arguments. The first argument is the "current time", where the animation start time is 0. The second argument is the initial value at the beginning of the animation (a Number). The third argument is the ending value minus the initial value. The fourth argument is the duration of the animation. The return value is the interpolated value for the current time. This is usually a value between the initial value and the ending value.

The value of this property must be a function object.

Flex includes a set of easing functions in the mx.effects.easing package.

Constructor Detail

TweenEffect

()

Constructor

public function TweenEffect(target:Object = null)

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Constructor.

Parameters

target:Object (default = null) — The Object to animate with this effect.

Method Detail

tweenEventHandler

()

method

protected function tweenEventHandler(event:mx.events:TweenEvent):void

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Called when the TweenEffect dispatches a TweenEvent. If you override this method, ensure that you call the super method.

Parameters

event:mx.events:TweenEvent — An event object of type TweenEvent.

Event Detail

tweenEnd

Event

Event Object Type: mx.events.TweenEvent
property TweenEvent.type = mx.events.TweenEvent.TWEEN_END

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Dispatched when the tween effect ends. This event corresponds to a call to the TweenEffectInstance.onTweenEnd() method.

When a tween effect plays a single time, this event occurs at the same time as an effectEnd event. If you configure the tween effect to repeat, it occurs at the end of every repetition of the effect, and the endEffect event occurs after the effect plays for the final time.

The TweenEvent.TWEEN_END constant defines the value of the event object's type property for a tweenEnd event.

The properties of the event object have the following values:

Property	Value
`bubbles`	false
`cancelable`	false
`currentTarget`	The Object that defines the event listener that handles the event. For example, if you use `myButton.addEventListener()` to register an event listener, myButton is the value of the `currentTarget`.
`target`	The Object that dispatched the event; it is not always the Object listening for the event. Use the `currentTarget` property to always access the Object listening for the event.
`value`	The value passed to the `onTweenEnd()` method.

tweenStart

Event

Event Object Type: mx.events.TweenEvent
property TweenEvent.type = mx.events.TweenEvent.TWEEN_START

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Dispatched when the tween effect starts, which corresponds to the first call to the onTweenUpdate() method. Flex also dispatches the first tweenUpdate event for the effect at the same time.

The Effect.effectStart event is dispatched before the tweenStart event.

The TweenEvent.TWEEN_START constant defines the value of the event object's type property for a tweenStart event.

The properties of the event object have the following values:

Property	Value
`bubbles`	false
`cancelable`	false
`currentTarget`	The Object that defines the event listener that handles the event. For example, if you use `myButton.addEventListener()` to register an event listener, myButton is the value of the `currentTarget`.
`target`	The Object that dispatched the event; it is not always the Object listening for the event. Use the `currentTarget` property to always access the Object listening for the event.
`value`	The value passed to the `onTweenUpdate()` method.

tweenUpdate

Event

Event Object Type: mx.events.TweenEvent
property TweenEvent.type = mx.events.TweenEvent.TWEEN_UPDATE

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Dispatched every time the tween effect updates the target. This event corresponds to a call to the TweenEffectInstance.onTweenUpdate() method.

The TweenEvent.TWEEN_UPDATE constant defines the value of the event object's type property for a tweenUpdate event.

The properties of the event object have the following values:

Property	Value
`bubbles`	false
`cancelable`	false
`currentTarget`	The Object that defines the event listener that handles the event. For example, if you use `myButton.addEventListener()` to register an event listener, myButton is the value of the `currentTarget`.
`target`	The Object that dispatched the event; it is not always the Object listening for the event. Use the `currentTarget` property to always access the Object listening for the event.
`value`	The value passed to the `onTweenUpdate()` method.

Examples How to use this example

SimpleTweenEffectExample.mxml

<?xml version="1.0"?>
<!-- Simple example to demonstrate the TweenEffect class. -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx">

    <fx:Script>
        <![CDATA[

            import mx.events.TweenEvent;

            // Event handler for the tweenUpdate and tweenEnd effects.
            private function tweenUpdateHandler(event:TweenEvent):void {
                // Access current width of the image.
                currentWidth.text="Current width (in pixels): " + String(event.value[0]);
            }

            // Event handler for the reset button.
            private function resetHandler():void {
                expand.end();
                img.width=30;
                currentWidth.text="Current width (in pixels): 30";
                img.height=60;
                button1.enabled=true;
            }
        ]]>
    </fx:Script>
    <fx:Declarations>
        <mx:Resize id="expand" target="{img}" widthTo="100" heightTo="200"
            duration="10000"
            tweenUpdate="tweenUpdateHandler(event);"
            tweenEnd="tweenUpdateHandler(event);"/>
    </fx:Declarations>

    <s:Panel title="Resize Effect Example" width="100%" height="100%" >
        <s:VGroup left="20" right="20" top="20" bottom="20">

            <s:Label width="100%" color="blue"
                text="Use the Button controls to resize the image."/>

            <s:HGroup width="100%">
                <mx:Image id="img" width="30" height="60"
                    source="@Embed(source='assets/Nokia_6630.png')"/>
                <s:Label id="currentWidth" height="20" width="100%"/>
            </s:HGroup>

            <s:Button id="button1" label="Start" click="expand.play(); button1.enabled=false;"/>
            <s:Button label="Pause" click="expand.pause();"/>
            <s:Button label="Resume" click="expand.resume();"/>
            <s:Button label="Reverse" click="expand.reverse();"/>
            <s:Button label="End" click="expand.end();"/>
            <s:Button label="Reset" click="resetHandler();"/>
        </s:VGroup>

    </s:Panel>
</s:Application>