只实现了一首歌的功能，音量控制，暂停等功能已经实现。

package {	import flash.display.MovieClip;	import flash.media.Sound;	import flash.media.SoundChannel;	import flash.net.URLRequest;	import flash.events.MouseEvent;	import fl.events.SliderEvent;	import flash.media.SoundTransform;	import flash.events.ProgressEvent;	import flash.events.Event;	public class MP3Main extends MovieClip	{		private var sound:Sound;		private var soundchannel:SoundChannel;		private var position:Number = 0;		private var soundtransform:SoundTransform;		private var jiazaitiao:JiaZaiTiao;		private var jiazaikuang:JiaZaiKuang;		public function MP3Main()		{			sound = new Sound();			soundchannel = new SoundChannel();			soundtransform = new SoundTransform();			jiazaitiao = new JiaZaiTiao();			jiazaikuang = new JiaZaiKuang();			jiazaitiao.scaleX = 0;			jiazaikuang.scaleX = 0;			jiazaitiao.x = 197;			jiazaitiao.y = 362;			xiayishou.label = "上一首";			shangyishou.label = "下一首";			btn1.label = "播放";			btn2.label = "停止";			slider.value = 10;			addChild(jiazaitiao);			addChild(xiayishou);			addChild(shangyishou);			sound.load(new URLRequest("Lenka-Trouble Is A Friend.mp3"));			slider.addEventListener(SliderEvent.CHANGE,onSliderHandler);			btn1.addEventListener(MouseEvent.CLICK,onClickHandler);			btn2.addEventListener(MouseEvent.CLICK,onStopHandler);			sound.addEventListener(ProgressEvent.PROGRESS,onJiaZaiKuangHandler);			sound.addEventListener(Event.COMPLETE,onJiaZaiTiaoHandler);			stage.addEventListener(Event.ENTER_FRAME,onEventHandler);		}		private function onSliderHandler(e:SliderEvent):void		{			soundtransform.volume = (e.target.value)* 0.2;			soundchannel.soundTransform = soundtransform;		}		private function onClickHandler(e:MouseEvent):void		{						if (btn1.label == "播放")			{				soundchannel = sound.play(position);				btn1.label = "暂停";			}			else			{				position = soundchannel.position;				soundchannel.stop();				btn1.label = "播放";			}		}		private function onStopHandler(e:MouseEvent):void		{			soundchannel.stop();			btn1.label = "播放";			position = 0;		}		private function onJiaZaiKuangHandler(e:ProgressEvent):void		{			jiazaikuang.scaleX = e.bytesLoaded / e.bytesTotal;		}		private function onJiaZaiTiaoHandler(e:Event):void		{			if (btn1.label == "播放")			{				soundchannel = sound.play();			}					  soundchannel.stop();		}		private function onEventHandler(e:Event):void		{		   jiazaitiao.scaleX = soundchannel.position / sound.length;		}	}}