android - FirebaseAuthUserCollisionException? -

i using firebase documentation use facebook login android application. able login users using google , twitter. when click on login facebook, button changing logout button. should redirect login success activity, because configured firebaseauth.authstatelistener.

i posting activity here, please let me know if doing wrong.

public class mainactivity extends appcompatactivity implements googleapiclient.onconnectionfailedlistener {      private static final string tag = "mainactivity";     private static final int google_rc_sign_in = 9001;     private static final int twitter_rc_sign_in = 140;      private firebaseauth mauth;     private firebaseauth.authstatelistener mauthstatelistener;      private googleapiclient mgoogleapiclient;     callbackmanager callbackmanager;     @bindview(r.id.google_signin_button) signinbutton mgooglesigninbutton;     @bindview(r.id.facebook_login_button) loginbutton mfacebookloginbutton;     @bindview(r.id.twitter_login_button) twitterloginbutton mtwitterloginbutton;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         twitterauthconfig authconfig = new twitterauthconfig(getstring(r.string.twitter_consumer_key), getstring(r.string.twitter_consumer_secret));         fabric.with(this, new twitter(authconfig));         facebooksdk.sdkinitialize(this);         setcontentview(r.layout.activity_main);          butterknife.bind(mainactivity.this);          googlesigninoptions gso = new googlesigninoptions.builder(googlesigninoptions.default_sign_in)                 .requestidtoken(getstring(r.string.default_web_client_id))                 .requestemail()                 .build();         mgoogleapiclient = new googleapiclient.builder(this)                 .enableautomanage(this,this)                 .addapi(auth.google_sign_in_api,gso)                 .build();          mauth = firebaseauth.getinstance();         mauthstatelistener = new firebaseauth.authstatelistener(){             @override             public void onauthstatechanged(@nonnull firebaseauth firebaseauth) {                 firebaseuser user = firebaseauth.getcurrentuser();                 if (user != null) {                     //user signed in                     log.v(tag, "yo baby");                     log.d(tag,"name"+user.getdisplayname());                     gotohome();                 } else {                     //do logic                 }             }         };          mgooglesigninbutton.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 intent signinintent = auth.googlesigninapi.getsigninintent(mgoogleapiclient);                 startactivityforresult(signinintent, google_rc_sign_in);             }         });          callbackmanager = callbackmanager.factory.create();         mfacebookloginbutton.setreadpermissions("email", "public_profile");         mfacebookloginbutton.registercallback(callbackmanager, new facebookcallback<loginresult>() {             @override             public void onsuccess(loginresult loginresult) {                 handlefacebookauthentication(loginresult.getaccesstoken());             }              @override             public void oncancel() {              }              @override             public void onerror(facebookexception error) {              }         });          mtwitterloginbutton.setcallback(new callback<twittersession>() {             @override             public void success(result<twittersession> result) {                 handletwitterauthentication(result.data);             }              @override             public void failure(twitterexception exception) {              }         });      }      @override     protected void onactivityresult(int requestcode, int resultcode, intent data) {         super.onactivityresult(requestcode, resultcode, data);          if (requestcode == google_rc_sign_in){             googlesigninresult result = auth.googlesigninapi.getsigninresultfromintent(data);             if (result.issuccess()) {                 googlesigninaccount account = result.getsigninaccount();                 handlegoogleauthentication(account);             } else {                 //google login failed             }         } else if (requestcode == twitter_rc_sign_in) {             mtwitterloginbutton.onactivityresult(requestcode,resultcode,data);         } else {             callbackmanager.onactivityresult(requestcode,resultcode,data);         }     }      private void handlegoogleauthentication(googlesigninaccount account) {         authcredential credential = googleauthprovider.getcredential(account.getidtoken(), null);         mauth.signinwithcredential(credential).addoncompletelistener(this, new oncompletelistener<authresult>() {             @override             public void oncomplete(@nonnull task<authresult> task) {                 if (task.issuccessful()) {                     //save credentials in google smart lock                 } else {                     //                 }             }         });     }      private void handlefacebookauthentication(accesstoken accesstoken) {         authcredential credential = facebookauthprovider.getcredential(accesstoken.gettoken());         mauth.signinwithcredential(credential).addoncompletelistener(this, new oncompletelistener<authresult>() {             @override             public void oncomplete(@nonnull task<authresult> task) {                 if (task.issuccessful()) {                     //save credentials in google smart lock                 } else {                  }             }         });     }      private void handletwitterauthentication(twittersession session) {         authcredential credential = twitterauthprovider.getcredential(session.getauthtoken().token, session.getauthtoken().secret);         mauth.signinwithcredential(credential).addoncompletelistener(this, new oncompletelistener<authresult>() {             @override             public void oncomplete(@nonnull task<authresult> task) {                 if (task.issuccessful()) {                     //save credentials in google smart lock                 } else {                  }             }         });     }     private void gotohome() {         startactivity(new intent(mainactivity.this, homeactivity.class));         finish();         return;     }      @override     protected void onstart() {         super.onstart();         mauth.addauthstatelistener(mauthstatelistener);     }      @override     protected void onstop() {         super.onstop();         if (mauthstatelistener != null) {             mauth.removeauthstatelistener(mauthstatelistener);         }     }      @override     public void onconnectionfailed(@nonnull connectionresult connectionresult) {      } } 

update1

finally understood reason why facebook login not working. because logged app using google signin. since email google , facebook same giving firebaseauthusercollisionexception. should have debugged application before post question in stackoverflow.

update2

i not closing question may faced situation me. , update solution firebaseauthusercollisionexception, dig more it.

i faced same problem , how got around with.
if task not successful, i'm checking whether exception thrown instanceof firebaseauthusercollisionexception. if yes, toast displayed user saying 'account email exists!'.

private void handlefacebookaccesstoken(final accesstoken token) {     log.d(tag, "handlefacebookaccesstoken:" + token);      authcredential credential = facebookauthprovider.getcredential(token.gettoken());     mauth.signinwithcredential(credential)             .addoncompletelistener(this, new oncompletelistener<authresult>() {                 @override                 public void oncomplete(@nonnull task<authresult> task) {                      if (!task.issuccessful()) {                         log.w(tag, "signinwithcredential", task.getexception());                         toast.maketext(getapplicationcontext(), "firebase facebook login failed",                                 toast.length_short).show();                          if(task.getexception() instanceof firebaseauthusercollisionexception) {                             toast.maketext(getapplicationcontext(), "user email id exists",                                     toast.length_short).show();                         }                         loginmanager.getinstance().logout();                     }                 }             }); }   

credit: check if given email exists