ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with sound
public function play(pos:int = 0):void
{
if (!this.isPlaying)
{
if (this.isReadyToPlay)
{
this.sc = this.s.play(pos);
this.sc.addEventListener(Event.SOUND_COMPLETE, onPlayComplete);
this.isPlaying = true;
}
}
}
this.playTimer = new Timer(this.progressInterval);
this.playTimer.addEventListener(TimerEvent.TIMER, onPlayTimer);
this.playTimer.start();
The play() method calls the Sound.play() method if the sound is ready to play. The resulting SoundChannel object
is stored in the sc property. The play() method then creates a Timer object that will be used to dispatch playback
progress events at regular intervals.
Displaying playback progress
Flash Player 9 and later, Adobe AIR 1.0 and later
Creating a Timer object to drive playback monitoring is complex operation that you should only have to code once.
Encapsulating this Timer logic in a reusable class like the SoundFacade class lets applications listen to the same kinds
of progress events when a sound is loading and when it is playing.
The Timer object that is created by the SoundFacade.play() method dispatches a TimerEvent instance every second.
The following onPlayTimer() method executes whenever a new TimerEvent arrives:
public function onPlayTimer(event:TimerEvent):void
{
var estimatedLength:int =
Math.ceil(this.s.length / (this.s.bytesLoaded / this.s.bytesTotal));
var progEvent:ProgressEvent =
new ProgressEvent(PLAY_PROGRESS, false, false, this.sc.position, estimatedLength);
this.dispatchEvent(progEvent);
}
The onPlayTimer() method implements the size estimation technique described in the section “Monitoring
playback” on page 451. Then it creates a new ProgressEvent instance with an event type of
SoundFacade.PLAY_PROGRESS, with the bytesLoaded property set to the current position of the SoundChannel
object and the bytesTotal property set to the estimated length of the sound data.
Pausing and resuming playback
Flash Player 9 and later, Adobe AIR 1.0 and later
The SoundFacade.play() method shown previously accepts a pos parameter corresponding to a starting position in
the sound data. If the pos value is zero, the sound starts playing from the beginning.
The SoundFacade.stop() method also accepts a pos parameter as shown here:
Last updated 6/6/2012
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