/**@param bMute 值为true时为关闭背景音乐。*/ 
@TargetApi(Build.VERSION_CODES.FROYO) 
public static boolean muteAudioFocus(Context context, boolean bMute) { 
  if(context == null){ 
    Log.d("ANDROID_LAB", "context is null."); 
    return false; 
  } 
  if(!VersionUtils.isrFroyo()){ 
    // 2.1以下的版本不支持下面的API：requestAudioFocus和abandonAudioFocus 
    Log.d("ANDROID_LAB", "Android 2.1 and below can not stop music"); 
    return false; 
  } 
  boolean bool = false; 
  AudioManager am = (AudioManager)context.getSystemService(Context.AUDIO_SERVICE); 
  if(bMute){ 
    int result = am.requestAudioFocus(null,AudioManager.STREAM_MUSIC,AudioManager.AUDIOFOCUS_GAIN_TRANSIENT); 
    bool = result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED; 
  }else{ 
    int result = am.abandonAudioFocus(null); 
    bool = result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED; 
  } 
  Log.d("ANDROID_LAB", "pauseMusic bMute="+bMute +" result="+bool); 
  return bool; 
}