iPhone OS 4.0:NSFileHandleDataAvailableNotification在文件结尾不提供回调

我对iPhone的开发有点陌生,所以要温柔一点!我支持一个应用程序,它从URL文件流加载wav文件,并通过音频队列播放。

我们在另一个线程中运行一个连续循环,如果检测到队列没有使用缓冲区,并且输入文件流已到达其末端,则停止该队列。反过来,我们检测文件流是否在 waitForDataInBackgroundAndNotify 上的回调 NSFileHandleDataAvailableNotification 对于流,通过检查 availableData 长度为0。

这在iOS 3.0下工作-我们在文件末尾收到0个可用数据的通知-但是在iOS 4.0上,我们似乎没有在文件结尾收到回调。这在OS4.0设备上发生,与目标OS版本无关。

希望相关代码:

数据可用回调:

- (void)readFileData:(NSNotification *)notification
{
  @try
  {
    NSData *data = [[notification object] availableData];

    if ([data length] == 0 && self.audioQueueState != AQS_END)
    {
      /***********************************************************************/
      /* We've hit the end of the data but it's possible that more may be    */
      /* appended to the file (if we're still downloading it) so we need to  */
      /* wait for the availability of more data.                             */
      /***********************************************************************/
      [self setFileStreamerState:FSS_END];
      [[notification object] waitForDataInBackgroundAndNotify];
    }
    else if (self.audioQueueState == AQS_END)
    {
      TRC_DBG(@"ignore read data as ending");
    }
    else
    {
      NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

      TRC_DBG(@"Read %d bytes", [data length]);

      [self setFileStreamerState:FSS_DATA];

      if (discontinuous)
      {
        TRC_DBG(@"AudioFileStreamParseBytes %d bytes, discontinuous", [data length]);
        err = AudioFileStreamParseBytes(audioFileStream, [data length], [data bytes], kAudioFileStreamParseFlag_Discontinuity);
        discontinuous = NO;
      }
      else
      {
        TRC_DBG(@"AudioFileStreamParseBytes %d bytes, continuous", [data length]);
        err = AudioFileStreamParseBytes(audioFileStream, [data length], [data bytes], 0);
      }

      /***********************************************************************/
      /* If error then get out, otherwise wait again for more data.          */
      /***********************************************************************/
      if (err != 0)
      {
        [self failWithErrorCode:AS_FILE_STREAM_PARSE_BYTES_FAILED];
      }
      else
      {
        [[notification object] waitForDataInBackgroundAndNotify];
      }

      [pool release];
    }
  }
  @catch (NSException *exception)
  {
    TRC_ERR(@"Exception: %@", exception);
    TRC_ERR(@"Exception reason: %@", [exception reason]);
    //[self failWithErrorCode:AS_FILE_AVAILABLE_DATA_FAILED];
  }
}