How to call another activity method in android studio? -

i have 2 different activities. first calls menu(base) if user logged in, have method display user information.

public class mainactivity extends actionbaractivity implements view.onclicklistener {      userlocalstore userlocalstore;     edittext etname, etage, etusername;     button blogout;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          etusername = (edittext) findviewbyid(r.id.etusername);         etname = (edittext) findviewbyid(r.id.etname);         etage = (edittext) findviewbyid(r.id.etage);         blogout = (button) findviewbyid(r.id.blogout);          blogout.setonclicklistener(this);          userlocalstore = new userlocalstore(this);     }      @override     public void onclick(view v) {         switch (v.getid()){             case r.id.blogout:                 userlocalstore.clearuserdata();                 userlocalstore.setuserloggedin(false);                 intent loginintent = new intent(this, login.class);                 startactivity(loginintent);                 break;         }     }      @override     protected void onstart() {         super.onstart();         if (authenticate() == true) {             startactivity(new intent(this, base.class));         }     }      private boolean authenticate() {         if (userlocalstore.getloggedinuser() == null) {             intent intent = new intent(this, login.class);             startactivity(intent);             return false;         }         return true;     }      public void displayuserdetails() {         user user = userlocalstore.getloggedinuser();         etusername.settext(user.username);         etname.settext(user.name);         etage.settext(user.age + "");     } } 

the second activity menu; activity has button called "butente" when clicked must show user info.

public class base extends activity implements view.onclicklistener {     button bdiario;     button butente;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_base);         bdiario = (button) findviewbyid(r.id.bdiario);         bdiario.setonclicklistener(this);         butente = (button) findviewbyid(r.id.butente);         butente.setonclicklistener(this);     }      @override     public void onclick(view v) {         switch (v.getid()){             case r.id.bdiario:                 startactivity(new intent(this, diary.class));              case r.id.butente:                 mainactivity prova = new mainactivity();                 prova.displayuserdetails();         }     } } 

how can when click button "butente" reminds me of other activity performing method "displayuserdetails()"?

mainactivity has layout contains views show user information. if in base, activity has different layout doesn't have views showing user information. can create dialog shows user information, or add additional views base show user information, or rearchitect application have activity shows user information , both mainactivity , base start activity show user information.

in case, absolutely positively cannot instantiate activity mainactivity using new keyword! android can instantiate activity components, because framework sets underlying context when that. keeps track of these components , manages lifecycle callbacks.