android - How can I extract string from OnPostExecute to my Main Activity -

i'm still new, repeat, new in android studio , i'm trying display place name,vicinity,lat , long using listview. got listview ready couldnt string onpostexecute. tried using https://stackoverflow.com/a/12575319/5776859 did not work @ all, or maybe didnt correctly. hope me or show me proper way string , double onpostexecute.

public class placesdisplaytask extends asynctask<object, integer,  list<hashmap<string,string>>> {       jsonobject googleplacesjson;     googlemap googlemap;      @override     public list<hashmap<string, string>> doinbackground(object... inputobj) {          list<hashmap<string, string>> googleplaceslist = null;         places placejsonparser = new places();          try {             googlemap = (googlemap) inputobj[0];             googleplacesjson = new jsonobject((string) inputobj[1]);             googleplaceslist = placejsonparser.parse(googleplacesjson);         } catch (exception e) {             log.d("exception", e.tostring());         }          return googleplaceslist;     }      @override     protected void onpostexecute(list<hashmap<string,string>> list) {          (int = 0; < 3; i++) {              hashmap<string, string> googleplace = list.get(i);             double lat = double.parsedouble(googleplace.get("lat"));             double lng = double.parsedouble(googleplace.get("lng"));             string placename = googleplace.get("place_name");             string vicinity = googleplace.get("vicinity");          }     } } 

a less tedious way accomplish you're trying perform whatever task requires returned value within onpostexecute(). can input references context using constructor , store them global variables use.

another way can set return type in signature of class list<hashmap<string, string>> , can call <placesdisplaytask object>.execute().get() method. make background process synchronous i.e. block ui thread, waiting on result.

the last alternative can think of involves use of delegate described in link you've posted.