public void initDownload() {
/**
* get download id from preferences.<br>
* if download id bigger than 0, means it has been downloaded, then query status and show right
* text;
*/
downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
downloadManagerPro = new DownloadManagerPro(downloadManager);
downloadId = PreferencesUtils.getLong(getBaseContext(), KEY_NAME_DOWNLOAD_ID);
completeReceiver = new CompleteReceiver();
/** register download success broadcast * */
registerReceiver(completeReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
initDownloaderDir();
}