Android: How to measure distance with gps -

i trying make application,which take latitude , longitude on current place of user. , count momentary,what distance travel user in km.

the "currentlat" , "currentlon" current latitude , longitude of user.but don't know latitude , longitude put "endlat" , "ednlon".

sorry bad english.

thanks in advance.

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i made app,but have 1 little problem. when started first time program,i value 5536 , when restarted program normal value 0.0

again sorry bad english. :)

and guys helping me,you best :)

  public class gps extends activity   {   textview display;     double currentlon=0 ;   double currentlat=0 ;   double lastlon = 0;   double lastlat = 0;   double distance;     public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_test);         display = (textview) findviewbyid(r.id.info);    locationmanager lm =(locationmanager) getsystemservice(location_service);                  lm.requestlocationupdates(lm.gps_provider, 0,0, loclist);                 location loc = lm.getlastknownlocation(lm.gps_provider);                  if(loc==null){                     display.settext("no gps location found");                     }                     else{                         //set current latitude , longitude                         currentlon=loc.getlongitude();                         currentlat=loc.getlatitude();                          }                 //set last latitude , longitude                 lastlat=currentlat;                 lastlon=currentlon ;   }     locationlistener loclist = new locationlistener(){     @override public void onlocationchanged(location location) {     // todo auto-generated method stub       //start location manager      locationmanager lm =(locationmanager) getsystemservice(location_service);        //get last location      location loc = lm.getlastknownlocation(lm.gps_provider);      //request new location       lm.requestlocationupdates(lm.gps_provider, 0,0, loclist);        //get new location       location loc2 = lm.getlastknownlocation(lm.gps_provider);        //get current lat , long      currentlat = loc.getlatitude();      currentlon = loc.getlongitude();       location locationa = new location("point a");         locationa.setlatitude(lastlat);         locationa.setlongitude(lastlon);      location locationb = new location("point b");         locationb.setlatitude(currentlat);         locationb.setlongitude(currentlon);          double distancemeters = locationa.distanceto(locationb);          double distancekm = distancemeters / 1000f;          display.settext(string.format("%.2f km",distancekm ));          }    @override public void onproviderdisabled(string provider) {     // todo auto-generated method stub  }    @override public void onproviderenabled(string provider) {     // todo auto-generated method stub  }    @override public void onstatuschanged(string provider, int status, bundle extras) {     // todo auto-generated method stub    }   };  } 

but don't know latitude , longitude put "endlat" , "ednlon".

endlat, endlon confusing name:

you should have lastlat, lastlon: lat,lon received in previous call of ongpsupdate, save e.g distancecalculator.lastlat distancecalculator object store lastlat, , lastlon

then should have curlat, curlon: current lat, lon delivered in ongpsupdate

then calculate distance (lastlat, lastlon) -> (curlat, curlon), , update distancecalculator.lastlat , lastlon.