auth_dialog.dart

FlatButton(
  color: Colors.blueGrey[800],
  hoverColor: Colors.blueGrey[900],
  highlightColor: Colors.black,
  onPressed: () async {
    if (_validateEmail(textControllerEmail.text) == null && _validatePassword(textControllerPassword.text) == null) {
      setState(() {
        _isRegistering = true;
      });
      await registerWithEmailPassword(textControllerEmail.text, textControllerPassword.text)
          .then((result) {
        print(result);
      }).catchError((error) {
        print('Registration Error: $error');
      });
    }
    setState(() {
      _isRegistering = false;
      _isEditingEmail = false;
    });
  },
  shape: RoundedRectangleBorder(
    borderRadius: BorderRadius.circular(15),
  ),
  child: Padding(
    padding: EdgeInsets.only(top: 15.0, bottom: 15.0),
    child: _isRegistering
        ? SizedBox(
            height: 16,
            width: 16,
            child: CircularProgressIndicator(
              strokeWidth: 2,
              valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
            ),
          )
        : Text(
            'Sign up',
            style: TextStyle(fontSize: 14, color: Colors.white),
          ),
  ),
)