| Package | mx.effects |
| Class | public class Tween |
| Inheritance | Tween  flash.events.EventDispatcher |
When defining tween effects, you typically create an instance
of the Tween class within your override of the
EffectInstance.play() method.
A Tween instance accepts the startValue,
endValue, and duration properties,
and an optional easing function to define the animation.
The Tween object invokes the
mx.effects.effectClasses.TweenEffectInstance.onTweenUpdate()
callback function on a regular interval on the effect instance
for the duration of the effect, passing to the
onTweenUpdate() method an interpolated value
between the startValue and endValue.
Typically, the callback function updates some property of the target object,
causing that object to animate over the duration of the effect.
When the effect ends, the Tween objects invokes the
mx.effects.effectClasses.TweenEffectInstance.onTweenEnd()
callback function, if you defined one.
See also
| Property | Defined by | ||
|---|---|---|---|
| duration : Number = 3000
Duration of the animation, in milliseconds.
| Tween | ||
| easingFunction : Function [write-only]
Sets the easing function for the animation.
| Tween | ||
| listener : Object
Object that is notified at each interval of the animation.
| Tween | ||
| Method | Defined by | ||
|---|---|---|---|
|
Tween(listener:Object, startValue:Object, endValue:Object, duration:Number = -1, minFps:Number = -1, updateFunction:Function = null, endFunction:Function = null)
Constructor.
| Tween | ||
|
endTween():void
Interrupt the tween, jump immediately to the end of the tween,
and invoke the
onTweenEnd() callback function. | Tween | ||
|
pause():void
Pauses the effect until you call the
resume() method. | Tween | ||
|
resume():void
Resumes the effect after it has been paused
by a call to the
pause() method. | Tween | ||
|
reverse():void
Plays the effect in reverse,
starting from the current position of the effect.
| Tween | ||
|
seek(playheadTime:Number):void
Advances the tween effect to the specified position.
| Tween | ||
|
setTweenHandlers(updateFunction:Function, endFunction:Function):void
By default, the Tween class invokes the
mx.effects.effectClasses.TweenEffectInstance.onTweenUpdate()
callback function on a regular interval on the effect instance
for the duration of the effect, and the optional
mx.effects.effectClasses.TweenEffectInstance.onTweenEnd()
callback function at the end of the effect duration. | Tween | ||
|
stop():void
Stops the tween, ending it without dispatching an event or calling
the Tween's endFunction or
onTweenEnd(). | Tween | ||
| duration | property |
public var duration:Number = 3000Duration of the animation, in milliseconds.
| easingFunction | property |
easingFunction:Function [write-only]
Sets the easing function for the animation.
The easing function is used to interpolate between
the startValue value and the endValue.
A trivial easing function does 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 a 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 (usually a value between the initial value and the ending value).
Flex includes a set of easing functions in the mx.effects.easing package.
Implementation public function set easingFunction(value:Function):void
| listener | property |
public var listener:ObjectObject that is notified at each interval of the animation.
| Tween | () | constructor |
public function Tween(listener:Object, startValue:Object, endValue:Object, duration:Number = -1, minFps:Number = -1, updateFunction:Function = null, endFunction:Function = null)Constructor.
When the constructor is called, the animation automatically starts playing.
Parameterslistener:Object — Object that is notified at each interval
of the animation. You typically pass the this
keyword as the value.
The listener must define the
onTweenUpdate() method and optionally the
onTweenEnd() method.
The former method is invoked for each interval of the animation,
and the latter is invoked just after the animation finishes.
|
|
startValue:Object — Initial value(s) of the animation.
Either a number or an array of numbers.
If a number is passed, the Tween interpolates
between this number and the number passed
in the endValue parameter.
If an array of numbers is passed,
each number in the array is interpolated.
|
|
endValue:Object — Final value(s) of the animation.
The type of this argument must match the startValue
parameter.
|
|
duration:Number (default = -1) |
|
minFps:Number (default = -1)onTweenUpdate() method should be called every second.
The tween code tries to call the onTweenUpdate()
method as frequently as possible (up to 100 times per second).
However, if the frequency falls below minFps,
the duration of the animation automatically increases.
As a result, an animation that temporarily freezes
(because it is not getting any CPU cycles) begins again
where it left off, instead of suddenly jumping ahead.
|
|
updateFunction:Function (default = null)listener.OnTweenUpdate()
|
|
endFunction:Function (default = null)listener.OnTweenEnd()
|
| endTween | () | method |
public function endTween():void
Interrupt the tween, jump immediately to the end of the tween,
and invoke the onTweenEnd() callback function.
| pause | () | method |
public function pause():void
Pauses the effect until you call the resume() method.
| resume | () | method |
public function resume():void
Resumes the effect after it has been paused
by a call to the pause() method.
| reverse | () | method |
public function reverse():voidPlays the effect in reverse, starting from the current position of the effect.
| seek | () | method |
public function seek(playheadTime:Number):voidAdvances the tween effect to the specified position.
ParametersplayheadTime:Number — The position, in milliseconds, between 0
and the value of the duration property.
|
| setTweenHandlers | () | method |
public function setTweenHandlers(updateFunction:Function, endFunction:Function):void
By default, the Tween class invokes the
mx.effects.effectClasses.TweenEffectInstance.onTweenUpdate()
callback function on a regular interval on the effect instance
for the duration of the effect, and the optional
mx.effects.effectClasses.TweenEffectInstance.onTweenEnd()
callback function at the end of the effect duration.
This method lets you specify different methods as the update and the end callback functions.
ParametersupdateFunction:Function — Specifies the update callback function.
|
|
endFunction:Function — Specifies the end callback function.
|
| stop | () | method |
public function stop():void
Stops the tween, ending it without dispatching an event or calling
the Tween's endFunction or onTweenEnd().