private SubmitListener submitListener = new SubmitListener() {
        @Override
        public void submitSuccess(DownloadInfo downloadInfo) {
            Log.d("Submit", "success submit, id = " + downloadInfo.getId());
        }

        @Override
        public void submitFail(Exception e) {
            Log.e("Submit", "submit failed", e);
        }
};
// path: parent directory to store your file
// filename: can be null; if not null, downloader will use it to save your file
YCDownloader.submit(url, path, filename, submitListener);

DownloadListener downloadListener = ...;
YCDownloader.registerDownloadListener(downloadListener);

// you should unregister it to avoid memory leak
// such as Activity.OnDestroy
YCDownloader.unregisterDownloadListener(downloadListener);

// attention: these methods should be called in worker thread
// query by id
YCDownloader.queryDownloadInfo(long id);
// state != CANCELED && state != FINISH
YCDownloader.queryActiveDownloadInfoList();
// state == DELETED
YCDownloader.queryDeletedDownloadInfoList();
// state == FINISH
YCDownloader.queryFinishedDownloadInfoList();

// limit your running task to 4
YCDownloader.setMaxRunningTask(4);

// limit your download speed to 512KB
// param <= 0 means no limit, run as fast as possible
YCDownloader.setSpeedLimit(512 * 1024);

// if true, the speed of sending progress-update message will slow down
YCDownloader.setAvoidFrameDrop(true);
// send progress update message interval at least 500ms
// only valid when setAvoidFrameDrop(true)
YCDownloader.setSendMessageInterval(500, TimeUnit.MILLISECONDS);

// If false, all running tasks are in WAITING state
YCDownloaer.setAllowDownload(true)

// Use configuration to update
YCDownloader.updateByConfiguration(Configuration);