Flash as3读取LRC同步歌词的类

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    用FLASH as写了一个用于读取LRC同步歌词的类，只要25行代码，完全用是用FLASH的字符串操作来分析标签的。

    下面就是这个类：

package LRC{

         public class readlrc {

         public function readlrcastime(mp3playtime:Number,gc:String):String {

                var qsd:int;//起始点

                var fhz:String;

                 for (var j:int=0; j < gc.length; j++) {

                              if (gc.charCodeAt(j) == 58) {

                                       if (int(gc.slice(j - 2,j)) * 60 + int(gc.slice(j + 1,j + 3)) == mp3playtime) {

                                                 var i:int=0;

                                                do {

                                                        i++;





if (gc.charCodeAt(j + i) == 93) {

                                                        qsd=j + i;

                                                           }

                                                        if (gc.charCodeAt(j + i) == 13) {

                                                                    fhz=gc.slice(qsd + 1,j + i);



                                                         }

                                               } while (gc.charCodeAt(j + i) != 13&&j+i<gc.length);

                                        }

                               }

                        }

                         return fhz;

                 }

           }

}

    将此文件保存为readlrc.as。

    注意：一定要把此AS文件放入一个名为LRC的文件夹中，才可以使用。

    下面就用一个小示例来说明如何用这个类，新建一个AS文件，写入以下代码：

package {

             import flash.display.MovieClip;



              import flash.events.Event;

            import flash.net.URLLoader;

              import flash.net.URLRequest;

              import flash.media.Sound;

             import flash.media.SoundChannel;

             import flash.system.System;

               import flash.text.TextField;

              import LRC.readlrc;

               public class mp3 extends MovieClip {

                         private var lrcreq:URLRequest=new URLRequest("日不落.lrc");

                          private var mp3url:URLRequest=new URLRequest("日不落.mp3");

                           private var mymp3:Sound=new Sound();

                           private var channel:SoundChannel=new SoundChannel();



                         private var lrcurl:URLLoader=new URLLoader();

                           private var tbgc:String;

                          private var mylrc:readlrc=new readlrc();

                         System.useCodePage=true;

                         public function mp3() {

                                  mymp3.load(mp3url);

                                  channel=mymp3.play();

                                  lrcurl.load(lrcreq);

                                    lrcurl.addEventListener(Event.COMPLETE,loaded);

                           }

                           private function enterframe(event:Event) {

                                     try {

                                             gc_txt.text=mylrc.readlrcastime(int(channel.position/1000),tbgc);

                                      } catch (error:Error) {

                                             //

                                       }

                             }



                              private function loaded(event:Event) {

                                            tbgc=String(event.target.data);

                                            addEventListener(Event.ENTER_FRAME,enterframe);

                              }

                  }

}

    保存此文件为mp3.as。

    写完后，我们还需要一个FLA文件来编译这些代码，新建一个FLA文件，名字随意，在场景中拖出一个动态文本域，实例名称填写gc_txt,在FLA文件的文档类中填写mp3，将此FLA文件与mp3.as文件，日不落.mp3文件，日不落.lrc文件和名为LRC的文件夹放入同一个目录下，测试影片，就可以看到效果了。

【责任编辑: lanier】