android - Why i didn't get Logout Button in Next Activity in Facebook Integration with sdk 4.0.1 -

i login facebook sdk 4.0.1 , goto second activity logout activity click on logout button , redirected again main activity got there again logout button login button change logout facebook sdk. please tell me what's wrong me. please tell me how logout button in next activity

public class  mainactivity extends fragmentactivity{        loginbutton loginbutton;      facebooksdk mfacebook;      private static final string[] permissions = new string[] {"public_profile", "user_photos", "read_stream", "email" };      callbackmanager callbackmanager;      sharedpreferences preferences;      string username, emailid, userfacebookid, userid;      url image_value;        public void oncreate(bundle savedinstancestate) {          super.oncreate(savedinstancestate);          facebooksdk.sdkinitialize(getapplicationcontext());          callbackmanager = callbackmanager.factory.create();          setcontentview(r.layout.activity_main);          system.out.println("inside oncreate  ");          preferences = getsharedpreferences("mydata", context.mode_world_writeable);            loginbutton = (loginbutton) findviewbyid(r.id.login_button);          loginbutton.setreadpermissions(permissions);          // if using in fragment  //        loginbutton.setfragment();            // callback registration          loginmanager.getinstance().registercallback(callbackmanager,                  new facebookcallback<loginresult>() {                      @override                      public void onsuccess(loginresult loginresult) {                            sharedpreferences.editor editor = preferences.edit();                          editor.putstring("accesstoken", loginresult.getaccesstoken().tostring());                          editor.apply();                            graphrequest request = graphrequest.newmerequest(loginresult.getaccesstoken(), new graphrequest.graphjsonobjectcallback() {                              @override                              public void oncompleted(jsonobject jsonobject, graphresponse graphresponse) {                                    try {                                      system.out.println("inside onsuccess  ");                                        userfacebookid = graphresponse.getjsonobject().getstring("id");                                      username = graphresponse.getjsonobject().getstring("name");                                      emailid = graphresponse.getjsonobject().getstring("email");                                      userid = graphresponse.getjsonobject().getstring("link");                                        try {                                          image_value = new url("http://graph.facebook.com/" + userfacebookid + "/picture?type=large");                                      } catch (malformedurlexception e) {                                          e.printstacktrace();                                      }                                      sharedpreferences.editor editor = preferences.edit();                                      editor.putstring("userfacebookid", userfacebookid);                                      editor.putstring("username", username);                                      editor.putstring("emailid", emailid);                                      editor.putstring("userid", userid);                                      editor.putstring("image_value", image_value.tostring());                                      editor.apply();                                        intent intent = new intent(mainactivity.this, logout.class);                                      startactivity(intent);                                    } catch (org.json.jsonexception e) {                                      e.printstacktrace();                                  }                              }                          });                          request.executeasync();                      }                        @override                      public void oncancel() {                          system.out.println("inside oncancel  ");                          // app code                      }                        @override                      public void onerror(facebookexception exception) {                            system.out.println("inside error  " + exception);                          // app code                      }                  });      }        @override      public void onbackpressed() {          super.onbackpressed();          finish();      }        @override      protected void onactivityresult(int requestcode, int resultcode, intent data) {          super.onactivityresult(requestcode, resultcode, data);          callbackmanager.onactivityresult(requestcode, resultcode, data);          system.out.println("inside onactivityresult  "+resultcode);      }  }

in second activity logout method,use following line ask loginmanager logout as

loginmanager.getinstance().logout(); 

so show "login" text on facebook login button in main activity.