java - AsyncTask doInBackground comes with big delay -

can explain why asynctask comes big delay , in 1 case, , when have wifi network there no internet connectivity on network.

what reason that, , there way make bigger priority on async task?

i have had problem before, solved adding onpreexecute in order check if there internet connection before attempting execute doinbackground, check out code below:

public class httpgetproduct extends asynctask<void,void,string> {         string result, rs;         jsonarray jarray;         string itemcode="",price,desc_ar,desc_en;          @override         protected void onpreexecute() {             super.onpreexecute();             isonline=ping(); // use ping if connecting local ip address      isonline= hasinternetconnection();// use if connecting internet          }          @override         protected string doinbackground(void... params) {             if(isonline) // executes if online              try {                 string link = "http://"+ip+"/pricecheckerws.asmx/get_product_data?barcode="+barcode;                 url url = new url(link);                 httpclient client = new defaulthttpclient();                 httpget request = new httpget();                 request.seturi(new uri(link));                 httpresponse response = client.execute(request);                  bufferedreader reader = new bufferedreader(new inputstreamreader(response.getentity().getcontent(), "utf-8"), 8);                 stringbuilder sb = new stringbuilder();                  string line = null;                 while ((line = reader.readline()) != null) {                     sb.append(line + "\n");                 }                 result = sb.tostring();                 // somthing result if need                  rs = "sucessful";             } catch (exception e) {                 rs = "fail";             }              return rs;         }         @override         protected void onpostexecute(string s) {             super.onpostexecute(s);            }     }  public boolean ping() {         string[] separated = ip.split(":");         string hostip=separated[0];         runtime runtime = runtime.getruntime();         try {              process ipprocess = runtime.exec("/system/bin/ping -c 1 " + hostip);             int     exitvalue = ipprocess.waitfor();             return (exitvalue == 0);          } catch (ioexception e)          { e.printstacktrace(); }         catch (interruptedexception e) { e.printstacktrace(); }          return false;     }  public boolean hasinternetconnection() {             try {                 connectivitymanager cm = (connectivitymanager) getsystemservice(context.connectivity_service);                 if (cm != null) {                     networkinfo = cm.getactivenetworkinfo();                     if (i != null) {                         if (!i.isconnected())                             return false;                         if (!i.isavailable())                             return false;                     }                     if (i == null)                         return false;                  } else                     return false;             }             catch (exception e){                 return false;             }             internet=true;             return true;         }