Sign.java

 private void signIn() {

        List<AuthUI.IdpConfig> providers = Arrays.asList(
                new AuthUI.IdpConfig.EmailBuilder().build(),
                new AuthUI.IdpConfig.GoogleBuilder().build());

        startActivityForResult(
                AuthUI.getInstance()
                        .createSignInIntentBuilder()
                        .setAvailableProviders(providers)
                        .setTheme(R.style.AppTheme
                        .setIsSmartLockEnabled(false)
                        .build(),
                RC_SIGN_IN);
                }