java - Intent to HomeActivity after login status success -

this loginactivity.java

this send login details httpasynctask .java

final button button = (button) findviewbyid(r.id.btnlogin);     button.setonclicklistener(new view.onclicklistener() {          public void onclick(view v) {              try {                  // email edit view value                 string email = emailet.gettext().tostring();                 // password edit view value                 string password = pwdet.gettext().tostring();                 // instantiate http request param object                 //                  requestparams params = new requestparams();                 // when email edit view , password edit view have values                 // other null                 if (utility.isnotnull(email) && utility.isnotnull(password)) {                     // when email entered valid                     if (utility.validate(email)) {                          //call async task                          jsonobject js = new httpasynctask(getapplicationcontext()).execute(email,password).get();                          toast.maketext(getapplicationcontext(), "asynctask started", toast.length_short).show();                      }                     // when email invalid                     else {                         toast.maketext(getapplicationcontext(),                                 "please enter valid email",                                 toast.length_long).show();                     }                 }                 // when of edit view control left blank                 else {                     toast.maketext(                             getapplicationcontext(),                             "please fill form, don't leave field blank",                             toast.length_long).show();                 }             } catch (exception ex) {              }          }     });   } } 

httpasynctask.java

public class httpasynctask extends asynctask<string, integer, jsonobject> {  private static inputstream stream = null; private static string api; private jsonobject responsejson = null; private context contxt; private activity activity;  public httpasynctask(context context) {      // api = apiurl;     this.contxt = context; }  // async task accept string array context array @override protected jsonobject doinbackground(string... params) {      string path = null;     string response = null;     hashmap<string, string> request = null;     jsonobject requestjson = null;     defaulthttpclient httpclient = null;     httppost httppost = null;     stringentity requeststring = null;     responsehandler<string> responsehandler = null;      // username , password     log.i("email", params[0]);     log.i("password", params[1]);      try {          path = "http://192.168.xxxxxxx";         new url(path);     } catch (malformedurlexception e) {          e.printstacktrace();     }      try {          // set api request         request = new hashmap<string, string>();         request.put(new string("email"), params[0]);         request.put(new string("password"), params[1]);         request.entryset().iterator();           requestjson = new jsonobject(request);         httpclient = new defaulthttpclient();         httppost = new httppost(path);         requeststring = new stringentity(requestjson.tostring());           httppost.setentity(requeststring);         httppost.setheader("content-type", "application/json");          // handles response         responsehandler = new basicresponsehandler();         response = httpclient.execute(httppost, responsehandler);          responsejson = new jsonobject(response);      } catch (exception e) {         log.e("buffer error", "error converting result " + e.tostring());     }     try {         responsejson = new jsonobject(response);     } catch (jsonexception e) {         log.e("json parser", "error parsing data " + e.tostring());     }      return responsejson;    }  @override protected void onpostexecute(jsonobject result) {     // todo auto-generated method stub     super.onpostexecute(result);     log.d("myasynctask", "received result: " + result); //here received result: {"status":"400"}  } 

my problem want know how direct activityhome when login success, if login error should display error message.

i tried in onpostexecute method

activity.startactivity(new intent(activity, activityhome.class)); 

but didn't work, app crashed.

first, have store response in jsonobject in onpostexecute method.

protected void onpostexecute(jsonobject result) {     // todo auto-generated method stub     super.onpostexecute(result);     if(responsejson!=null){         try{             jsonobject jobjstatus=new jsonobject(responsejson);             string status=jobjstatus.getstring("status");             if(status.equals("success"){                 startactivity(new intent(mainactivity.this, secondactivity.class);             }         }catch(){         }     } }