问AWS文件传输错误

EN

 /**
     * This state represents a transfer that has been queued, but has not yet
     * started
     */
    WAITING,
    /**
     * This state represents a transfer that is currently uploading or
     * downloading data
     */
    IN_PROGRESS,
    /**
     * This state represents a transfer that is paused
     */
    PAUSED,
    /**
     * This state represents a transfer that has been resumed and queued for
     * execution, but has not started to actively transfer data
     */
    RESUMED_WAITING,
    /**
     * This state represents a transfer that is completed
     */
    COMPLETED,
    /**
     * This state represents a transfer that is canceled
     */
    CANCELED,
    /**
     * This state represents a transfer that has failed
     */
    FAILED,

    /**
     * This state represents a transfer that is currently on hold, waiting for
     * the network to become available
     */
    WAITING_FOR_NETWORK,
    /**
     * This state represents a transfer that is a completed part of a multi-part
     * upload. This state is primarily used internally and there should be no
     * need to use this state.
     */
    PART_COMPLETED,
    /**
     * This state represents a transfer that has been requested to cancel, but
     * the service processing transfers has not yet fulfilled this request. This
     * state is primarily used internally and there should be no need to use
     * this state.
     */
    PENDING_CANCEL,
    /**
     * This state represents a transfer that has been requested to pause by the
     * client, but the service processing transfers has not yet fulfilled this
     * request. This state is primarily used internally and there should be no
     * need to use this state.
     */
    PENDING_PAUSE,
    /**
     * This state represents a transfer that has been requested to pause by the
     * client because the network has been loss, but the service processing
     * transfers has not yet fulfilled this request. This state is primarily
     * used internally and there should be no need to use this state.
     */
    PENDING_NETWORK_DISCONNECT,
    /**
     * This is an internal value used to detect if the current transfer is in an
     * unknown state
     */
    UNKNOWN;

TransferObserver observer   =   transferUtil.download(Bucketname, key, file);

        observer.setTransferListener(new TransferListener() {
            @Override
            public void onStateChanged(int i, TransferState transferState) {
                Log.d("AWS download state", transferState.toString());
                if (transferState == TransferState.COMPLETED) {
                }else if(transferState == TransferState.CANCELED){



                }else if(transferState == TransferState.FAILED){


                }else if((transferState == TransferState.WAITING) || (transferState == TransferState.WAITING_FOR_NETWORK)){

                }
            }

            @Override
            public void onProgressChanged(int i, long l, long l1) {


            }

            @Override
            public void onError(int i, Exception e) {
                Log.e("aws error", e.toString());

            }
        });