TOPIC:

class CheckURLInDocument extends AsyncTask<Void,Void,String>{
        private ArrayList<FileDownload>urlDownload;
        private Context context;

        public CheckURLInDocument(Context context){
            this.context=context;
        }
        @Override
        protected String doInBackground(Void... params) {
            try{
                urlDownload=new ArrayList<FileDownload>();
                Book book = Session.currentBook;
                String path = Session.basePath;
                int total = m_doc.GetPageCount();
                attachments = new ArrayList<Attachment> ();
                for (int i = 0; i < total; i++) {
                    Page page = m_doc.GetPage (i);
                    page.ObjsStart();
                    int annots = page.GetAnnotCount();
                    for (int j = 0; j < annots; j++) {
                       Page.Annotation annotation = page.GetAnnot(j);
                        if (annotation.GetURI() != null && annotation.GetURI() != "") {
                            if (annotation.GetURI().contains(".mp3")) {
                                File file = new File(path,  annotation.GetURI());
                                if (!file.exists()) {                                 
                                    urlDownload.add(
                                            new FileDownload(file,
                                            URLEncoder.encode(book.getDesc(), "utf-8") + "/AUDIOS/" + annotation.GetURI(),
                                            "Audio: " + annotation.GetURI()));

                                }
                            }
                            if (annotation.GetURI().contains(".mp4")) {
                                String[] names = annotation.GetURI().split("\\|");
                                Attachment a = new Attachment();
                                a.setPage(i);
                                a.setTitle(names[1]);
                                a.setName(names[0]);
                                attachments.add(a);

                                File file = new File(path,  names[0]);
                                if (!file.exists()) {
                                    urlDownload.add(new FileDownload(
                                            file,
                                            URLEncoder.encode(book.getDesclibro(), "utf-8") + "/VIDEOS/" + names[0],
                                            "Video: " + names[1]));
                                }                                
                            }
                        }
                        annotation=null;
                    }
                    if(page!=null)
                        page.Close();
                    page=null;
                }
            }catch(Exception ex) {
                ex.printStackTrace();
            }
            String res=downloadFiles();
            return res;
        }
        @Override
        protected void onPostExecute(String aVoid) {
            super.onPostExecute(aVoid);
            mAdapterAttachments=new AdapterAttachment(getApplicationContext(),attachments);
            mListAttachments.setAdapter(mAdapterAttachments);
            Toast.makeText(context,aVoid,Toast.LENGTH_SHORT);
        }
        public String downloadFiles(){
            String url="http://.../../..";
            String url2="http://.../../..";
            String shortURL="http://....";
            String shortURL2="http://....";
            String res="";
            String mURL=null;
            if(Util.isConnectedToServer(shortURL2)){
                mURL=url2;
            }else{
                if(Util.isConnectedToServer(shortURL)) {
                    mURL = url;
                }
            }
            if(mURL!=null){
                String servicestring = Context.DOWNLOAD_SERVICE;
                downloadmanager = (DownloadManager) context.getSystemService(servicestring);
                for(int i=0;i<urlDownload.size();i++){
                    FileDownload myFile=urlDownload.get(i);
                    String filename=myFile.getUrl();
                    File finalPath=myFile.getFinalPath();
                    Uri uri = Uri
                            .parse(mURL + filename.replaceAll("\\+", "%20"));
                    DownloadManager.Request request = new DownloadManager.Request(uri);
                    request.setVisibleInDownloadsUi(true);
                    request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);
                    request.setTitle(myFile.getName());
                    request.setDescription("Downloading Resource "+filename);
                    request.setDestinationUri(Uri.fromFile(finalPath));

                    downloadmanager.enqueue(request);

                }
                urlDownload=null;
                res="Downloading Resources";
            }else{
                res="No Connection to Server";
            }
            return res;
        }
    }