handle IDLE state in exo player

@Override
public void onPlayerError(ExoPlaybackException error) {
  if (error.type == ExoPlaybackException.TYPE_SOURCE) {
    IOException cause = error.getSourceException();
    if (cause instanceof HttpDataSourceException) {
      // An HTTP error occurred.
      HttpDataSourceException httpError = (HttpDataSourceException) cause;
      // This is the request for which the error occurred.
      DataSpec requestDataSpec = httpError.dataSpec;
      // It's possible to find out more about the error both by casting and by
      // querying the cause.
      if (httpError instanceof HttpDataSource.InvalidResponseCodeException) {
        // Cast to InvalidResponseCodeException and retrieve the response code,
        // message and headers.
      } else {
        // Try calling httpError.getCause() to retrieve the underlying cause,
        // although note that it may be null.
      }
    }
  }
}