android - Passing arguments to AsyncTask, and returning results -

i have application long calculations, , show progress dialog while done. far have found threads/handlers, didn't work, , found out asynctask.

in application use maps markers on it, , have implemented ontap function call method have defined. method creates dialog yes/no buttons, , call asynctask if yes clicked. question how pass arraylist<string> asynctask (and work there), , how new arraylist<string> result asynctask?

the code of method looks this:

string curloc = current.tostring(); string itemdesc = item.mdescription;  arraylist<string> passing = new arraylist<string>(); passing.add(itemdesc); passing.add(curloc);  arraylist<string> result = new arraylist<string>();  new calc_stanica().execute(passing,result);  string minim = result.get(0); int min = integer.parseint(minim);  string glons = result.get(1); string glats = result.get(2);  double glon = double.parsedouble(glons); double glat = double.parsedouble(glats);  geopoint g = new geopoint(glon, glat); string korisni_linii = result.get(3); 

so, see, send string array list "passing" asynctask, , "result" string array list it. , calc_stanica assyctask class looks this:

public class calc_stanica extends asynctask<arraylist<string>, void, arraylist<string>> {     progressdialog dialog;      @override     protected void onpreexecute() {         dialog = new progressdialog(baraj_mapa.this);         dialog.settitle("calculating...");         dialog.setmessage("please wait...");         dialog.setindeterminate(true);         dialog.show();     }      protected arraylist<string> doinbackground(arraylist<string>... passing) {          //some calculations...          return something; //???     }      protected void onpostexecute(void unused) {         dialog.dismiss();     } 

so question how elements of "passing" array list in asynctask doinbackground method (and use them there), , how return array list use in main method (the "result" array list)?

change method this:

string curloc = current.tostring(); string itemdesc = item.mdescription; arraylist<string> passing = new arraylist<string>(); passing.add(itemdesc); passing.add(curloc); new calc_stanica().execute(passing); //no need pass in result list 

and change async task implementation

public class calc_stanica extends asynctask<arraylist<string>, void, arraylist<string>> { progressdialog dialog;      @override     protected void onpreexecute() {         dialog = new progressdialog(baraj_mapa.this);         dialog.settitle("calculating...");         dialog.setmessage("please wait...");         dialog.setindeterminate(true);         dialog.show();     }      protected arraylist<string> doinbackground(arraylist<string>... passing) {         arraylist<string> result = new arraylist<string>();         arraylist<string> passed = passing[0]; //get passed arraylist          //some calculations...          return result; //return result     }      protected void onpostexecute(arraylist<string> result) {         dialog.dismiss();         string minim = result.get(0);         int min = integer.parseint(minim);         string glons = result.get(1);         string glats = result.get(2);         double glon = double.parsedouble(glons);         double glat = double.parsedouble(glats);         geopoint g = new geopoint(glon, glat);         string korisni_linii = result.get(3);     } 

upd:

if want have access task starting context, easiest way override onpostexecute in place:

new calc_stanica() {     protected void onpostexecute(arraylist<string> result) {       // here have access context in execute called in first place.        // you'll have mark local variables final though..      } }.execute(passing);