java - app crashes when intent passes variable to another activity -

i making app tracks user , tracks user in theory animal. app goes this, register username , pass when done user can log map reentering correct username , password. issues begin. upon creation of screen map loads users current location , auto sends sms "animals" phone request gps details, sends 2 sms messages, 1 containing gps information. have smsreceiver class reads information , extracts longitude , latitude data, converts double passes map activity converted lnglat variable , displayed on google map marker. issue having can take several minutes sms return gps information, when done , intent used send coordinates map page button must clicked longitude , latitude combined animalcoordinate , marker shown, because og time gap imposible press button @ same time sms retrieved , causes crash data being sent smsreceiver class nothing on other side, , if take intent out of onclick method same thing happens in reverse, map runs intent informaion not there yet , crashes. appreciated has been nightmare.

i sorry if overcomplicated explanation, wanted ake sure explained best could. code below 2 classes.

map class  public class mainscreen extends fragmentactivity implements locationlistener { private googlemap map; private locationmanager locationmanager; private string provider; final context context = this;       @override    protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main_screen);     map = ((supportmapfragment)getsupportfragmentmanager().     findfragmentbyid(r.id.map)).getmap();      locationmanager service = (locationmanager) getsystemservice(location_service);     boolean enabledgps = service             .isproviderenabled(locationmanager.gps_provider);     boolean enabledwifi = service             .isproviderenabled(locationmanager.network_provider);      // check if enabled , if not send user gsp settings     if (!enabledgps) {         toast.maketext(this, "gps signal not found", toast.length_long).show();         intent intent = new intent(settings.action_location_source_settings);         startactivity(intent);     }      locationmanager = (locationmanager) getsystemservice(context.location_service);     // define criteria how select locatioin provider -> use     // default     criteria criteria = new criteria();     provider = locationmanager.getbestprovider(criteria, false);     location location = locationmanager.getlastknownlocation(provider);      // initialize location fields     if (location != null) {         toast.maketext(this, "selected provider " + provider,                 toast.length_short).show();         onlocationchanged(location);     } else {          //do     }     // sets map type "hybrid"     map.setmaptype(googlemap.map_type_hybrid);      bundle b = getintent().getextras();       double lat =  location.getlatitude();     double lng = location.getlongitude();     toast.maketext(this, "location " + lat+","+lng,             toast.length_long).show();     latlng usercoordinate = new latlng(lat, lng);     marker user = map.addmarker(new markeroptions()     .position(usercoordinate)     .title("you here")     .icon(bitmapdescriptorfactory.fromresource(r.drawable.ic_launcher)));     //move camera instantly user zoom of 15.     map.movecamera(cameraupdatefactory.newlatlngzoom(usercoordinate, 15));      // zoom in, animating camera.     map.animatecamera(cameraupdatefactory.zoomto(18), 2000, null);      //sends sms 'animal phone'       string phoneno = "***********";       string sms = "gpslocation";        try {         smsmanager smsmanager = smsmanager.getdefault();         smsmanager.sendtextmessage(phoneno, null, sms, null, null);         toast.maketext(getapplicationcontext(), "sms sent!",                     toast.length_long).show();       } catch (exception e) {         toast.maketext(getapplicationcontext(),             "sms faild, please try again later!",             toast.length_long).show();         e.printstacktrace();       }      }  public void map_help(view view) {     //method button      alertdialog.builder alertdialogbuilder = new alertdialog.builder(             context);          // set title         alertdialogbuilder.settitle("help");          // set dialog message         alertdialogbuilder      .setmessage("click 'pet' button display pets location." +                     "this can take few minutes retrieve.")             .setcancelable(false)     .setpositivebutton("ok",new   dialoginterface.onclicklistener(){                 public void onclick(dialoginterface dialog,int id)        {                     // if button clicked, close                     // current activity                     dialog.cancel();                 }               });             // create alert dialog             alertdialog alertdialog = alertdialogbuilder.create();                  // show                 alertdialog.show();                                 };  public void find_pet(view view) {        //string phoneno = "07516909014";      // string sms = "gpslocation";       // try {     //  smsmanager smsmanager = smsmanager.getdefault();         //smsmanager.sendtextmessage(phoneno, null, sms, null, null);         //toast.maketext(getapplicationcontext(), "sms sent!",             //      toast.length_long).show(); //    } catch (exception e) {     //  toast.maketext(getapplicationcontext(),         //  "sms faild, please try again later!",             //toast.length_long).show();     //  e.printstacktrace();       //} }  public void show_pet(view view) {     //gets coordinates smsreceiver     bundle b = getintent().getextras();     double animallat = b.getdouble("key");      bundle d = getintent().getextras();     double animallon = d.getdouble("key1");      latlng animalcoordinate = new latlng(animallat, animallon);     //adds pets marker on map     marker animal = map.addmarker(new markeroptions()     .position(animalcoordinate)     .title("your pet here")     .icon(bitmapdescriptorfactory.fromresource(r.drawable.ic_launcher))); }   /* request updates @ startup */ @override protected void onresume() {     super.onresume();     locationmanager.requestlocationupdates(provider, 400, 1, this); }  /* remove locationlistener updates when activity paused */ @override protected void onpause() {     super.onpause();     locationmanager.removeupdates(this); }  @override public void onlocationchanged(location location) {   }   @override public void onproviderdisabled(string provider) {     toast.maketext(this, "enabled new provider " + provider,             toast.length_short).show();  }   @override public void onproviderenabled(string provider) {     toast.maketext(this, "disabled provider " + provider,             toast.length_short).show();  }   @override public void onstatuschanged(string provider, int status, bundle extras) {     // todo auto-generated method stub  }  } 

smsreceiver class

public class smsreceiver extends broadcastreceiver { string lat = null; string lon = null; string message = null; final smsreceiver context = this;  @override public void onreceive(context context, intent intent)  {     //---get sms message passed in---     bundle bundle = intent.getextras();             smsmessage[] msgs = null;     string str = "";                 if (bundle != null)     {         //---retrieve sms message received---         object[] pdus = (object[]) bundle.get("pdus");         msgs = new smsmessage[pdus.length];                     (int i=0; i<msgs.length; i++){             msgs[i] = smsmessage.createfrompdu((byte[])pdus[i]);                             str += msgs[i].getmessagebody().tostring();          }}              message = str.tostring();             string[] test = message.split("");             char[] test2 = test[1].tochararray();              //if first character of sms c read gps information             if (test2[0] == 'c' || test2[0] =='c')             {             lat = message.substring(45, 56);             lon = message.substring(67, 78);              double animallat=double.parsedouble(lat);             double animallon=double.parsedouble(lon);              //pass coordinates mainscreen             intent = new intent(getapplicationcontext(), mainscreen.class);             bundle b = new bundle();             b.putdouble("key", animallat);             a.putextras(b);             startactivity(a);              intent c = new intent(getapplicationcontext(), mainscreen.class);             bundle d = new bundle();             d.putdouble("key1", animallon);             c.putextras(d);             startactivity(c);              }else {             }            }  private void startactivity(intent a) {     // todo auto-generated method stub  }  private context getapplicationcontext() {     // todo auto-generated method stub     return null; }} 

i want apologize layout of code, first time have pasted code on site. again.

to honest, i'm not sure button talking. 1 saw in alertdialog unless missed something. anyway, can disable button until whatever data has value or can nothing in onclick() if null

//inside button if (data != null) {      ...do stuff in here } 

if need more clarification please indicate in code data talking , button think idea.