class - Android Variable Usage within Classes -

i have class within activity , can not use variables in subclass in activity class. why happening?!

this in subclass:

       try              {                 httpresponse response = client.execute(getrequest);                 inputstream jsonstream = response.getentity().getcontent();                 bufferedreader reader = new bufferedreader(new inputstreamreader(jsonstream));                 stringbuilder builder = new stringbuilder();                 string line;                 while((line = reader.readline()) != null)                 {                     builder.append(line);                 }                 string jsondata = builder.tostring();                 log.e("data", jsondata);                 person = new jsonobject(jsondata);                 email = person.getstring("email");               } catch (clientprotocolexception e) {                 e.printstacktrace();                 log.e("no data", "nothing");             } catch (ioexception e) {                 e.printstacktrace();                 log.e("no data", "nothing");             } catch (jsonexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }             log.e("email", email);             return null;         } 

i right value of email in log.e output when try assign text view string email in activity class, wont work , crashes emulator.

  textview myemailview = (textview) findviewbyid(r.id.textview15);    myemailview.settext(email);