authentication - 1 User Multiple Accounts 1 android app transfer data from login activity to splashscreen activity -

i'm developing app user must able switch between accounts. of i'm able allow app 1 account log in. how can allow user create account , switch between them in android app?

update:-

i'm able auth google button (firebase)

i want in app!

in login.class stored value of uid got firebase. want send data splashscreen check if uid==null redirect login , if uid !=null redirect mainactivity.

login.class

 string mypreferences = "myprefs" ;                     string uid = "uidkey";                     sharedpreferences sharedpreferences = login.this.getpreferences(context.mode_private);                     sharedpreferences.editor editor = sharedpreferences.edit();                     editor.putstring("uid", uid);                     editor.putboolean("is_logged_before",true); //this line trick                     editor.commit();                     toast.maketext(login.this,"uid:"+uid,toast.length_long).show();                      string uid1 = sharedpreferences.getstring("uid", "");                     log.i("shareduser",uid1);                      intent = new intent(login.this,splashscreen.class);                     i.putextra("message",uid1);                     startactivity(i); 

splashscreen

public class splashscreen extends activity {

private static int splash_time_out = 2000;   @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.splashscreen);      new handler().postdelayed(new runnable() {         @override         public void run() {              /*bundle bundle = getintent().getextras();             string message = bundle.getstring("message");             log.i("received uid",message);*/              intent homeintent = new intent(splashscreen.this, login.class);             startactivity(homeintent);             finish();            }     },splash_time_out);  } 

}

the scope of answer wide. please ask genuine doubts related programming only.

looks need implement auto-login of user. need use shared preferences.

after successful login of user, store username , password in shared preferences.

then when user again tries login need check sharedpref check username , password. again depends on type of authentication implementing can session id user.

check answer that

also account picker check answer