android – 如何获取Soundpool的持续时间

这是我的代码

String source_path = "/sdcard/varun/audio.mp3";



mSoundPool = new SoundPool(10,Au@L_429_7@manager.STREAM_MUSIC,0);
mSoundPool.setOnLoadCompleteListener(new OnLoadCompleteListener() {
public void onLoadComplete(SoundPool soundPool,int samplEID,int status) {
                            loaded = true;
                        }
                    });
                    sound1  = mSoundPool.load(source_path,1);

                    hand1.postDelayed(new Runnable() {

                        public void run() {
                            // TODO Auto-generated method stub
                            if (loaded) {
                                mSoundPool.play(sound1,1,time - 1,1);
                                System.out.println("playing=== a");
                            }
                        }
                    },21000);

在这里,我将值硬编码为21000,但我需要获取音频文件的持续时间,因为持续时间随每个文件而变化.我正在使用android 2.2

如何实现这一点请帮忙？